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Rationalism | Define Rationalism at Dictionary.com

[rash-uh-nl-iz-uhm]

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Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, Random House, Inc. 2018

Collins English Dictionary – Complete & Unabridged 2012 Digital Edition William Collins Sons & Co. Ltd. 1979, 1986 HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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Critical rationalism – Wikipedia

Critical rationalism is an epistemological philosophy advanced by Karl Popper. Popper wrote about critical rationalism in his works: The Logic of Scientific Discovery,[1] The Open Society and its Enemies,[2] Conjectures and Refutations,[3] The Myth of the Framework,[4] and Unended Quest.[5]

Critical rationalists hold that scientific theories and any other claims to knowledge can and should be rationally criticized, and (if they have empirical content) can and should be subjected to tests which may falsify them. Thus claims to knowledge may be contrastingly and normatively evaluated. They are either falsifiable and thus empirical (in a very broad sense), or not falsifiable and thus non-empirical. Those claims to knowledge that are potentially falsifiable can then be admitted to the body of empirical science, and then further differentiated according to whether they are retained or are later actually falsified. If retained, further differentiation may be made on the basis of how much subjection to criticism they have received, how severe such criticism has been, and how probable the theory is, with the least[6] probable theory that still withstands attempts to falsify it being the one to be preferred. That it is the least[6] probable theory that is to be preferred is one of the contrasting differences between critical rationalism and classical views on science, such as positivism, who hold that one should instead accept the most probable theory. (The least probable theory is the one with the highest information content and most open to future falsification.) Critical Rationalism as a discourse positioned itself against what its proponents took to be epistemologically relativist philosophies, particularly post-modernist or sociological approaches to knowledge. Critical rationalism has it that knowledge is objective (in the sense of being embodied in various substrates and in the sense of not being reducible to what humans individually “know”), and also that truth is objective (exists independently of social mediation or individual perception, but is “really real”).

However, this contrastive, critical approach to objective knowledge is quite different from more traditional views that also hold knowledge to be objective. (These include the strong rationalism of the Enlightenment, the verificationism of the logical positivists, or approaches to science based on induction, a supposed form of logical inference which critical rationalists reject, in line with David Hume.) For criticism is all that can be done when attempting to differentiate claims to knowledge, according to the critical rationalist. Reason is the organon of criticism, not of support; of tentative refutation, not of proof.

Supposed positive evidence (such as the provision of “good reasons” for a claim, or its having been “corroborated” by making successful predictions) actually does nothing to bolster, support, or prove a claim, belief, or theory.

In this sense, critical rationalism turns the normal understanding of a traditional rationalist, and a realist, on its head. Especially the view that a theory is better if it is less likely to be true is in direct opposition to the traditional positivistic view, which holds that one should seek for theories that have a high probability.[6] Popper notes that this “may illustrate Schopenhauer’s remark that the solution of a problem often first looks like a paradox and later like a truism”. Even a highly unlikely theory that conflicts current observation (and is thus false, like “all swans are white”) must be considered to be better than one which fits observations perfectly, but is highly probable (like “all swans have a color”). This insight is the crucial difference between naive falsificationism and critical rationalism. The lower probability theory is favoured by critical rationalism because the higher the informative content of a theory the lower will be its probability, for the more information a statement contains, the greater will be the number of ways in which it may turn out to be false. The rationale behind this is simply to make it as easy as possible to find out whether the theory is false so that it can be replaced by one that is closer to the truth. It is not meant as a concession to justificationist epistemology, like assuming a theory to be “justifiable” by asserting that it is highly unlikely and yet fits observation.

Critical rationalism rejects the classical position that knowledge is justified true belief; it instead holds the exact opposite: That, in general, knowledge is unjustified untrue unbelief. It is unjustified because of the non-existence of good reasons. It is untrue, because it usually contains errors that sometimes remain unnoticed for hundreds of years. And it is not belief either, because scientific knowledge, or the knowledge needed to build a plane, is contained in no single person’s mind. It is only available as the content of books.

William Warren Bartley compared critical rationalism to the very general philosophical approach to knowledge which he called “justificationism”. Most justificationists do not know that they are justificationists. Justificationism is what Popper called a “subjectivist” view of truth, in which the question of whether some statement is true, is confused with the question of whether it can be justified (established, proven, verified, warranted, made well-founded, made reliable, grounded, supported, legitimated, based on evidence) in some way.

According to Bartley, some justificationists are positive about this mistake. They are nave rationalists, and thinking that their knowledge can indeed be founded, in principle, it may be deemed certain to some degree, and rational.

Other justificationists are negative about these mistakes. They are epistemological relativists, and think (rightly, according to the critical rationalist) that you cannot find knowledge, that there is no source of epistemological absolutism. But they conclude (wrongly, according to the critical rationalist) that there is therefore no rationality, and no objective distinction to be made between the true and the false.

By dissolving justificationism itself, the critical rationalist regards knowledge and rationality, reason and science, as neither foundational nor infallible, but nevertheless does not think we must therefore all be relativists. Knowledge and truth still exist, just not in the way we thought.

The rejection of “positivist” approaches to knowledge occurs due to various pitfalls that positivism falls into.

1. The nave empiricism of induction was shown to be illogical by Hume. A thousand observations of some event A coinciding with some event B does not allow one to logically infer that all A events coincide with B events. According to the critical rationalist, if there is a sense in which humans accrue knowledge positively by experience, it is only by pivoting observations off existing conjectural theories pertinent to the observations, or off underlying cognitive schemas which unconsciously handle perceptions and use them to generate new theories. But these new theories advanced in response to perceived particulars are not logically “induced” from them. These new theories may be wrong. The myth that we induce theories from particulars is persistent because when we do this we are often successful, but this is due to the advanced state of our evolved tendencies. If we were really “inducting” theories from particulars, it would be inductively logical to claim that the sun sets because I get up in the morning, or that all buses must have drivers in them (if you’ve never seen an empty bus).

2. Popper and David Miller showed in 1983[7] that evidence supposed to partly support a hypothesis can, in fact, only be neutral to, or even counter-support to the hypothesis.

3. Related to the point above, David Miller,[8] attacks the use of “good reasons” in general (including evidence supposed to support the excess content of a hypothesis). He argues that good reasons are neither attainable, nor even desirable. Basically, the case, which Miller calls “tediously familiar”, is that all arguments purporting to give valid support for a claim are either circular or question-begging. That is, if one provides a valid deductive argument (an inference from premises to a conclusion) for a given claim, then the content of the claim must already be contained within the premises of the argument (if it is not, then the argument is ampliative and so is invalid). Therefore, the claim is already presupposed by the premises, and is no more “supported” than are the assumptions upon which the claim rests, i.e. begging the question.

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Critical rationalism – Wikipedia

What is CR? – critical rationalism blogcritical …

I like to think of CR (critical rationalism) as a kind of evolving philosophical tradition concerning how we should approach knowledge. It is the Socratic method only with a little bit of modern awareness. While most philosophical traditions regard knowledge as something that has to be certain and justified, CR takes the view that we dont have ultimate answers, but knowledge is nevertheless possible. Truth is an endless quest.

The modern founder of critical rationalism was Karl Popper. Popper pointed out we can never justify anything, we merely criticize and weed out bad ideas and work with whats left. Poppers initial emphasis was on empirical science, where he solved the problem of induction, something that had been haunting philosophers and scientists for centuries. The problem of induction is this. No matter how many times weve seen an apple fall to the ground after weve dropped it, do we have any way to prove the same thing will happen next time we drop it. The answer is no. What Popper pointed out is that you can never justify any scientific theory, but you can falsify it. If I were to claim that all swans were white, one black swan would falsify my theory. In this way, science moves forward by weeding out bad theories, so to speak.

Popper said that science moves forward through a method of conjecture and refutation. While Popper was primarily interested in science, he often commented on political problems as well. Popper liked to emphasize the need for an open society, a society where people can speak out and criticize. After all, if science progresses through refutations, criticizing becomes essential. We need to speak out and therefore we need the freedom to do so. Popper was against any form of government that didnt give people the chance to speak out. Poppers thinking could probably best be summed up in this quote, I may be wrong and you may be right, and by an effort, we may get nearer to the truth.

Popper worked hard to expand his ideas, and so have several other people. CR should not be viewed as one mans philosophy, but as a growing philosophical tradition. One in which several people have contributed and are still contributing. One notable person was William Warren Bartley, III. Bartley worked towards expanding the idea of critical rationalism to cover all areas of knowledge, not just empirical science. Bartley felt that while in almost all areas of knowledge we seek justification, we should instead seek criticism. While nothing can ever be justified in any ultimate sense, certainly we can see error and weed it out. This is true whether we are dealing with empirical science and perhaps even knowledge of what is ethical. An important part of Bartleys thinking could probably best be summed up in this quote, How can our intellectual life and institutions, our tradition, and even our etiquette, sensibility, manners and customs, and behavior patterns, be arranged so as to expose our beliefs, conjectures, ideologies, policies, positions, programs, sources of ideas, traditions, and the like, to optimum criticism, so as at once to counteract and eliminate as much intellectual error as possible, and also so as to contribute to and insure the fertility of the intellectual econiche: to create an environment in which not only negative criticism but also positive creation of ideas, and the development of rationality, are truly inspired.

Neither Bartley or Popper have exhaustively explored the full potential of the CR philosophical tradition. Indeed, there are unlimited possibilities. While CR often emphasizes criticism, it also encourages new approaches and creative thinking. We need to come up with as many new ideas as we can, then let the process of criticism weed out the less workable ones. As CR accepts that the truth is out there and we are working towards it, it is actually a very optimistic philosophical tradition. Perhaps the most optimistic among the big three philosophical traditions. What are the big three traditions. Let me give you a quick summary.

One, dogmatism. Decide that you are privy to ultimate truth and then just follow that truth no matter what. Does such an attitude contribute to fanaticism? Perhaps.

Two, pessimism. Decide that truth is impossible, relative, random, meaningless. Just do whatever you want because nothing matters anyway. Does such an attitude contribute to random violence? Perhaps.

Three, critical rationalism, the truth is out there, but no one has a monopoly on it, so lets work together to try and get a little closer to it. Does such an attitude contribute to progress and mutual respect? More than likely.

If youd like more details than this then thats what this blog is for, please look around and explore.

Matt Dioguardi, blog administrator

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What is CR? – critical rationalism blogcritical …

Rationalism, Continental | Internet Encyclopedia of Philosophy

Continental rationalism is a retrospective category used to group together certain philosophers working in continental Europe in the 17th and 18th centuries, in particular, Descartes, Spinoza, and Leibniz, especially as they can be regarded in contrast with representatives of British empiricism, most notably, Locke, Berkeley, and Hume. Whereas the British empiricists held that all knowledge has its origin in, and is limited by, experience, the Continental rationalists thought that knowledge has its foundation in the scrutiny and orderly deployment of ideas and principles proper to the mind itself. The rationalists did not spurn experience as is sometimes mistakenly alleged; they were thoroughly immersed in the rapid developments of the new science, and in some cases led those developments. They held, however, that experience alone, while useful in practical matters, provides an inadequate foundation for genuine knowledge.

The fact that Continental rationalism and British empiricism are retrospectively applied terms does not mean that the distinction that they signify is anachronistic. Leibnizs New Essays on Human Understanding, for instance, outlines stark contrasts between his own way of thinking and that of Locke, which track many features of the rationalist/empiricist distinction as it tends to be applied in retrospect. There was no rationalist creed or manifesto to which Descartes, Spinoza, and Leibniz all subscribed (nor, for that matter, was there an empiricist one). Nevertheless, with due caution, it is possible to use the Continental rationalism category (and its empiricist counterpart) to highlight significant points of convergence in the philosophies of Descartes, Spinoza, and Leibniz, inter alia. These include: (1) a doctrine of innate ideas; (2) the application of mathematical method to philosophy; and (3) the use of a priori principles in the construction of substance-based metaphysical systems.

According to the Historisches Worterbuch der Philosophie, the word rationaliste appears in 16th century France, as early as 1539, in opposition to empirique. In his New Organon, first published in 1620 (in Latin), Francis Bacon juxtaposes rationalism and empiricism in memorable terms:

Those who have treated of the sciences have been either empiricists [Empirici] or dogmatists [Dogmatici]. Empiricists [Empirici], like ants, simply accumulate and use; Rationalists [Rationales], like spiders, spin webs from themselves; the way of the bee is in between: it takes material from the flowers of the garden and the field; but it has the ability to convert and digest them. (The New Organon, p. 79; Spedding, 1, 201)

Bacons association of rationalists with dogmatists in this passage foreshadows Kants use of the term dogmatisch in reference, especially, to the Wolffian brand of rationalist philosophy prevalent in 18th century Germany. Nevertheless, Bacons use of rationales does not refer to Continental rationalism, which developed only after the New Organon, but rather to the Scholastic philosophy that dominated the medieval period. Moreover, while Bacon is, in retrospect, often considered the father of modern empiricism, the above-quoted passage shows him no friendlier to the empirici than to the rationales. Thus, Bacons juxtaposition of rationalism and empiricism should not be confused with the distinction as it develops over the course of the 17th and 18th centuries, although his imagery is certainly suggestive.

The distinction appears in an influential form as the backdrop to Kants critical philosophy (which is often loosely understood as a kind of synthesis of certain aspects of Continental rationalism and British empiricism) at the end of the 18th century. However, it was not until the time of Hegel in the first half of the 19th century that the terms rationalism and empiricism were applied to separating the figures of the 17th and 18th centuries into contrasting epistemological camps in the fashion with which we are familiar today. In his Lectures on the History of Philosophy, Hegel describes an opposition between a priori thought, on the one hand, according to which the determinations which should be valid for thought should be taken from thought itself, and, on the other hand, the determination that we must begin and end and think, etc., from experience. He describes this as the opposition between Rationalismus and Empirismus (Werke 20, 121).

Perhaps the best recognized and most commonly made distinction between rationalists and empiricists concerns the question of the source of ideas. Whereas rationalists tend to think (with some exceptions discussed below) that some ideas, at least, such as the idea of God, are innate, empiricists hold that all ideas come from experience. Although the rationalists tend to be remembered for their positive doctrine concerning innate ideas, their assertions are matched by a rejection of the notion that all ideas can be accounted for on the basis of experience alone. In some Continental rationalists, especially in Spinoza, the negative doctrine is more apparent than the positive. The distinction is worth bearing in mind, in order to avoid the very false impression that the rationalists held to innate ideas because the empiricist alternative had not come along yet. (In general, the British empiricists came after the rationalists.) The Aristotelian doctrine, nihil in intellectu nisi prius in sensu (nothing in the intellect unless first in the senses), had been dominant for centuries, and it was in reaction against this that the rationalists revived in modified form the contrasting Platonic doctrine of innate ideas.

Descartes distinguishes between three kinds of ideas: adventitious (adventitiae), factitious (factae), and innate (innatae). As an example of an adventitious idea, Descartes gives the common idea of the sun (yellow, bright, round) as it is perceived through the senses. As an example of a factitious idea, Descartes cites the idea of the sun constructed via astronomical reasoning (vast, gaseous body). According to Descartes, all ideas which represent true, immutable, and eternal essences are innate. Innate ideas, for Descartes, include the idea of God, the mind, and mathematical truths, such as the fact that it pertains to the nature of a triangle that its three angles equal two right angles.

By conceiving some ideas as innate, Descartes does not mean that children are born with fully actualized conceptions of, for example, triangles and their properties. This is a common misconception of the rationalist doctrine of innate ideas. Descartes strives to correct it in Comments on a Certain Broadsheet, where he compares the innateness of ideas in the mind to the tendency which some babies are born with to contract certain diseases: it is not so much that the babies of such families suffer from these diseases in their mothers womb, but simply that they are born with a certain faculty or tendency to contract them (CSM I, 304). In other words, innate ideas exist in the mind potentially, as tendencies; they are then actualized by means of active thought under certain circumstances, such as seeing a triangular figure.

At various points, Descartes defends his doctrine of innate ideas against philosophers (Hobbes, Gassendi, and Regius, inter alia) who hold that all ideas enter the mind through the senses, and that there are no ideas apart from images. Descartes is relatively consistent on his reasons for thinking that some ideas, at least, must be innate. His principal line of argument proceeds by showing that there are certain ideas, for example, the idea of a triangle, that cannot be either adventitious or factitious; since ideas are either adventitious, factitious, or innate, by process of elimination, such ideas must be innate.

Take Descartes favorite example of the idea of a triangle. The argument that the idea of a triangle cannot be adventitious proceeds roughly as follows. A triangle is composed of straight lines. However, straight lines never enter our mind via the senses, since when we examine straight lines under a magnifying lens, they turn out to be wavy or irregular in some way. Since we cannot derive the idea of straight lines from the senses, we cannot derive the idea of a true triangle, which is made up of straight lines, through the senses. Sometimes Descartes makes the point in slightly different terms by insisting that there is no similarity between the corporeal motions of the sense organs and the ideas formed in the mind on the occasion of those motions (CSM I, 304; CSMK III, 187). One such dissimilarity, which is particularly striking, is the contrast between the particularity of all corporeal motions and the universality that pure ideas can attain when conjoined to form necessary truths. Descartes makes this point in clear terms to Regius:

I would like our author to tell me what the corporeal motion is that is capable of forming some common notion to the effect that things which are equal to a third thing are equal to each other, or any other he cares to take. For all such motions are particular, whereas the common notions are universal and bear no affinity with, or relation to, the motions. (CSM I, 304-5)

Next, Descartes has to show that the idea of a triangle is not factitious. This is where the doctrine of true and immutable natures comes in. For Descartes, if, for example, the idea that the three angles of a triangle are equal to two right angles were his own invention, it would be mutable, like the idea of a gold mountain, which can be changed at whim into the idea of a silver mountain. Instead, when Descartes thinks about his idea of a triangle, he is able to discover eternal properties of it that are not mutable in this way; hence, they are not invented (CSMK III, 184).

Since, therefore, the triangle can be neither adventitious nor factitious, it must be innate; that is to say, the mind has an innate tendency or power to form this idea from its own purely intellectual resources when prompted to do so.

Descartes insistence that there is no similarity between the corporeal motions of our sense organs and the ideas formed in the mind on the occasion of those motions raises a difficulty for understanding how any ideas could be adventitious. Since none of our ideas have any similarity to the corporeal motions of the sense organs even the idea of motion itself it seems that no ideas can in fact have their origin in a source external to the mind. The reason that we have an idea of heat in the presence of fire, for instance, is not, then, because the idea is somehow transmitted by the fire. Rather, Descartes thinks that God designed us in such a way that we form the idea of heat on the occasion of certain corporeal motions in our sense organs (and we form other sensory ideas on the occasion of other corporeal motions). Thus, there is a sense in which, for Descartes, all ideas are innate, and his tripartite division between kinds of ideas becomes difficult to maintain.

Per his so-called doctrine of parallelism, Spinoza conceives the mind and the body as one and the same thing, conceived under different attributes (to wit, thought and extension). (See Benedict de Spinoza: Metaphysics.) As a result, Spinoza denies that there is any causal interaction between mind and body, and so Spinoza denies that any ideas are caused by bodily change. Just as bodies can be affected only by other bodies, so ideas can be affected only by other ideas. This does not mean, however, that all ideas are innate for Spinoza, as they very clearly are for Leibniz (see below). Just as the body can be conceived to be affected by external objects conceived under the attribute of extension (that is, as bodies), so the mind can (as it were, in parallel) be conceived to be affected by the same objects conceived under the attribute of thought (that is, as ideas). Ideas gained in this way, from encounters with external objects (conceived as ideas) constitutes knowledge of the first kind, or imagination, for Spinoza, and all such ideas are inadequate, or in other words, confused and lacking order for the intellect. Adequate ideas, on the other hand, which can be formed via Spinozas second and third kinds of knowledge (reason and intuitive knowledge, respectively), and which are clear and distinct and have order for the intellect, are not gained through chance encounters with external objects; rather, adequate ideas can be explained in terms of resources intrinsic to the mind. (For more on Spinozas three kinds of knowledge and the distinction between adequate and inadequate ideas, see Benedict de Spinoza: Epistemology.)

The mind, for Spinoza, just by virtue of having ideas, which is its essence, has ideas of what Spinoza calls common notions, or in other words, those things which are equally in the part and in the whole. Examples of common notions include motion and rest, extension, and indeed God. Take extension for example. To think of any body however small or however large is to have a perfectly complete idea of extension. So, insofar as the mind has any idea of body (and, for Spinoza, the human mind is the idea of the human body, and so always has ideas of body), it has a perfectly adequate idea of extension. The same can be said for motion and rest. The same can also be said for God, except that God is not equally in the part and in the whole of extension only, but of all things. Spinoza treats these common notions as principles of reasoning. Anything that can be deduced on their basis is also adequate.

It is not clear if Spinozas common notions should be considered innate ideas. Spinoza speaks of active and passive ideas, and adequate and inadequate ideas. He associates the former with the intellect and the latter with the imagination, but innate idea is not an explicit category in Spinozas theory of ideas as it is in Descartes and also Leibnizs. Common notions are not in the mind independent of the minds relation with its object (the body); nevertheless, since it is the minds nature to be the idea of the body, it is part of the minds nature to have common notions. Commentators differ over the question of whether Spinoza had a positive doctrine of innate ideas; it is clear, however, that he denied that all ideas come about through encounters with external objects; moreover, he believed that those ideas which do come about through encounters with external objects are of an inferior epistemic value than those produced through the minds own intrinsic resources; this is enough to put him in the rationalist camp on the question of the origin of ideas.

Of the three great rationalists, Leibniz propounded the most thoroughgoing doctrine of innate ideas. For Leibniz, all ideas are strictly speaking innate. In a general and relatively straightforward sense, this viewpoint is a direct consequence of Leibnizs conception of individual substance. According to Leibniz, each substance is a world apart, independent of everything outside of itself except for God. Thus all our phenomena, that is to say, all the things that can ever happen to us, are only the results of our own being (L, 312); or, in Leibnizs famous phrase from the Monadology, monads have no windows, meaning there is no way for sensory data to enter monads from the outside. In this more general sense, then, to give an explanation for Leibnizs doctrine of innate ideas would be to explain his conception of individual substance and the arguments and considerations which motivate it. (See Section 4, b, iii, below for a discussion of Leibnizs conception of substance; see also Gottfried Leibniz: Metaphysics.) This would be to circumvent the issues and questions which are typically at the heart of the debate over the existence of innate ideas, which concern the extent to which certain kinds of perceptions, ideas, and propositions can be accounted for on the basis of experience. Although Leibnizs more general reasons for embracing innate ideas stem from his unique brand of substance metaphysics, Leibniz does enter into the debate over innate ideas, as it were, addressing the more specific questions regarding the source of given kinds of ideas, most notably in his dialogic engagement with Lockes philosophy, New Essays on Human Understanding.

Due to Leibnizs conception of individual substance, nothing actually comes from a sensory experience, where a sensory experience is understood to involve direct concourse with things outside of the mind. However, Leibniz does have a means for distinguishing between sensations and purely intellectual thoughts within the framework of his substance metaphysics. For Leibniz, although each monad or individual substance expresses (or represents) the entire universe from its own unique point of view, it does so with a greater or lesser degree of clarity and distinctness. Bare monads, such as comprise minerals and vegetation, express the rest of the world only in the most confused fashion. Rational minds, by contrast, have a much greater proportion of clear and distinct perceptions, and so express more of the world clearly and distinctly than do bare monads. When an individual substance attains a more perfect expression of the world (in the sense that it attains a less confused expression of the world), it is said to act; when its expression becomes more confused, it is said to be acted upon. Using this distinction, Leibniz is able to reconcile the terms of his philosophy with everyday conceptions. Although, strictly speaking, no monad is acted upon by any other, nor acts upon any other directly, it is possible to speak this way, just as, Leibniz says, Copernicans can still speak of the motion of the sun for everyday purposes, while understanding that the sun does not in fact move. It is in this sense that Leibniz enters into the debate concerning the origin of our ideas.

Leibniz distinguishes between ideas (ides) and thoughts (penses) (or, sometimes, notions (notions) or concepts (conceptus)). Ideas exist in the soul whether we actually perceive them or are aware of them or not. It is these ideas that Leibniz contends are innate. Thoughts, by contrast is Leibnizs designation for ideas which we actually form or conceive at any given time. In this sense, thoughts can be formed on the basis of a sensory experience (with the above caveats regarding the meaning a sensory experience can have in Leibnizs thought) or on the basis of an internal experience, or a reflection. Leibniz alternatively characterizes our ideas as aptitudes, preformations, and as dispositions to represent something when the occasion for thinking of it arises. On multiple occasions, Leibniz uses the metaphor of the veins present in marble to illustrate his understanding of innate ideas. Just as the veins dispose the sculptor to shape the marble in certain ways, so do our ideas dispose us to have certain thoughts on the occasion of certain experiences.

Leibniz rejects the view that the mind cannot have ideas without being aware that it has them. (See Gottfried Leibniz: Philosophy of Mind.) Much of the disagreement between Locke and Leibniz on the question of innate ideas turns on this point, since Locke (at least as Leibniz represents him in the New Essays) is not able to make any sense out of the notion that the mind can have ideas without being aware of them. Much of Leibnizs defense of his innate ideas doctrine takes the form of replying to Lockes charge that it is absurd to hold that the mind could think (that is, have ideas) without being aware of it.

Leibniz marshals several considerations in support of his view that the mind is not always aware of its ideas. The fact that we can store many more ideas in our understanding than we can be aware of at any given time is one. Leibniz also points to the phenomenology of attention; we do not attend to everything in our perceptual field at any given time; rather we focus on certain things at the expense of others. To convey a sense of what it might be like for the mind to have perceptions and ideas in a dreamless sleep, Leibniz asks the reader to imagine subtracting our attention from perceptual experience; since we can distinguish between what is attended to and what is not, subtracting attention does not eliminate perception altogether.

While such considerations suggest the possibility of innate ideas, they do not in and of themselves prove that innate ideas are necessary to explain the full scope of human cognition. The empiricist tends to think that if innate ideas are not necessary to explain cognition, then they should be abandoned as gratuitous metaphysical constructs. Leibniz does have arguments designed to show that innate ideas are needed for a full account of human cognition.

In the first place, Leibniz recalls favorably the famous scenario from Platos Meno where Socrates teaches a slave boy to grasp abstract mathematical truths merely by asking questions. The anecdote is supposed to indicate that mathematical truths can be generated by the mind alone, in the absence of particular sensory experiences, if only the mind is prompted to discover what it contains within itself. Concerning mathematics and geometry, Leibniz remarks: one could construct these sciences in ones study and even with ones eyes closed, without learning from sight or even from touch any of the needed truths (NE, 77). So, on these grounds, Leibniz contends that without innate ideas, we could not explain the sorts of cognitive capacities exhibited in the mathematical sciences.

A second argument concerns our capacity to grasp certain necessary or eternal truths. Leibniz says that necessary truths can be suggested, justified, and confirmed by experience, but that they can be proved only by the understanding alone (NE, 80). Leibniz does not explain this point further, but he seems to have in mind the point later made by both Hume and Kant (to different ends), that experience on its own can never account for the kind of certainty that we find in mathematical and metaphysical truths. For Leibniz, if it can be granted that we can be certain of propositions in mathematics and metaphysics and Leibniz thinks this must be granted recourse must be had to principles innate to the mind in order to explain our ability to be certain of such things.

It is worth noting briefly the position of Nicolas Malebranche on innate ideas, since Malebranche is often considered among the rationalists, yet he denied the doctrine of innate ideas. Malebranches reasons for rejecting innate ideas were anything but empiricist in nature, however. His leading objection stems from the infinity of ideas that the mind is able to form independently of the senses; as an example, Malebranche cites the infinite number of triangles of which the mind could in principle, albeit not in practice, form ideas. Unlike Descartes and Leibniz, who view innate ideas as tendencies or dispositions to form certain thoughts under certain circumstances, Malebranche understands them as fully formed entities that would have to exist somehow in the mind were they to exist there innately. Given this conception, Malebranche finds it unlikely that God would have created so many things along with the mind of man (The Search After Truth, p. 227). Since God already contains the ideas of all things within Himself, Malebranche thinks that it would be much more economical if God were simply to reveal to us the ideas of things that already exist in him rather than placing an infinity of ideas in each human mind. Malebranches tenet that we see all things in God thus follows upon the principle that God always acts in the simplest ways. Malebranche finds further support for this doctrine from the fact that it places human minds in a position of complete dependence on God. Thus, if Malebranches rejection of innate ideas distinguishes him from other rationalists, it does so not from an empiricist standpoint, but rather because of the extent to which his position on ideas is theologically motivated.

In one sense, what it means to be a rationalist is to model philosophy on mathematics, and, in particular, geometry. This means that the rationalist begins with definitions and intuitively self-evident axioms and proceeds thence to deduce a philosophical system of knowledge that is both certain and complete. This at least is the goal and (with some qualifications to be explored below) the claim. In no work of rationalist philosophy is this procedure more apparent than in Spinozas Ethics, laid out famously in the geometrical manner (more geometrico). Nevertheless, Descartes main works (and those of Leibniz as well), although not as overtly more geometrico as Spinozas Ethics, are also modelled after geometry, and it is Descartes celebrated methodological program that first introduces mathematics as a model for philosophy.

Perhaps Descartes clearest and most well-known statement of mathematics role as paradigm appears in the Discourse on the Method:

Those long chains of very simple and easy reasonings, which geometers customarily use to arrive at their most difficult demonstrations, had given me occasion to suppose that all the things which can fall under human knowledge are interconnected in the same way. (CSM I, 120)

However, Descartes promotion of mathematics as a model for philosophy dates back to his early, unfinished work, Rules for the Direction of the Mind. It is in this work that Descartes first outlines his standards for certainty that have since come to be so closely associated with him and with the rationalist enterprise more generally.

In Rule 2, Descartes declares that henceforth only what is certain should be valued and counted as knowledge. This means the rejection of all merely probable reasoning, which Descartes associates with the philosophy of the Schools. Descartes admits that according to this criterion, only arithmetic and geometry thus far count as knowledge. But Descartes does not conclude that only in these disciplines is it possible to attain knowledge. According to Descartes, the reason that certainty has eluded philosophers has as much to do with the disdain that philosophers have for the simplest truths as it does with the subject matter. Admittedly, the objects of arithmetic and geometry are especially pure and simple, or, as Descartes will later say, clear and distinct. Nevertheless, certainty can be attained in philosophy as well, provided the right method is followed.

Descartes distinguishes between two ways of achieving knowledge: through experience and through deduction [] [W]e must note that while our experiences of things are often deceptive, the deduction or pure inference of one thing from another can never be performed wrongly by an intellect which is in the least degree rational [] (CSM I, 12). This is a clear statement of Descartes methodological rationalism. Building up knowledge through accumulated experience can only ever lead to the sort of probable knowledge that Descartes finds lacking. Pure inference, by contrast, can never go astray, at least when it is conducted by right reason. Of course, the truth value of a deductive chain is only as good as the first truths, or axioms, whose truth the deductions preserve. It is for this reason that Descartes method relies on intuition as well as deduction. Intuition provides the first principles of a deductive system, for Descartes. Intuition differs from deduction insofar as it is not discursive. Intuition grasps its object in an immediate way. In its broadest outlines, Descartes method is just the use of intuition and deduction in the orderly attainment and preservation of certainty.

In subsequent Rules, Descartes goes on to elaborate a more specific methodological program, which involves reducing complicated matters step by step to simpler, intuitively graspable truths, and then using those simple truths as principles from which to deduce knowledge of more complicated matters. It is generally accepted by scholars that this more specific methodological program reappears in a more iconic form in the Discourse on the Method as the four rules for gaining knowledge outlined in Part 2. There is some doubt as to the extent to which this more specific methodological program actually plays any role in Descartes mature philosophy as it is expressed in the Meditations and Principles (see Garber 2001, chapter 2). There can be no doubt, however, that the broader methodological guidelines outlined above were a permanent feature of Descartes thought.

In response to a request to cast his Meditations in the geometrical style (that is, in the style of Euclids Elements), Descartes distinguishes between two aspects of the geometrical style: order and method, explaining:

The order consists simply in this. The items which are put forward first must be known entirely without the aid of what comes later; and the remaining items must be arranged in such a way that their demonstration depends solely on what has gone before. I did try to follow this order very carefully in my Meditations [] (CSM II, 110)

Elsewhere, Descartes contrasts this order, which he calls the order of reasons, with another order, which he associates with scholasticism, and which he calls the order of subject-matter (see CSMK III, 163). What Descartes understands as geometrical order or the order of reasons is just the procedure of starting with what is most simple, and proceeding in a step-wise, deliberate fashion to deduce consequences from there. Descartes order is governed by what can be clearly and distinctly intuited, and by what can be clearly and distinctly inferred from such self-evident intuitions (rather than by a concern for organizing the discussion into neat topical categories per the order of subject-matter)

As for method, Descartes distinguishes between analysis and synthesis. For Descartes, analysis and synthesis represent different methods of demonstrating a conclusion or set of conclusions. Analysis exhibits the path by which the conclusion comes to be grasped. As such, it can be thought of as the order of discovery or order of knowledge. Synthesis, by contrast, wherein conclusions are deduced from a series of definitions, postulates, and axioms, as in Euclids Elements, for instance, follows not the order in which things are discovered, but rather the order that things bear to one another in reality. As such, it can be thought of as the order of being. God, for example, is prior to the human mind in the order of being (since God created the human mind), and so in the synthetic mode of demonstration the existence of God is demonstrated before the existence of the human mind. However, knowledge of ones own mind precedes knowledge of God, at least in Descartes philosophy, and so in the analytic mode of demonstration the cogito is demonstrated before the existence of God. Descartes preference is for analysis, because he thinks that it is superior in helping the reader to discover the things for herself, and so in bringing about the intellectual conversion which it is the Meditations goal to effectuate in the minds of its readers. According to Descartes, while synthesis, in laying out demonstrations systematically, is useful in preempting dissent, it is inferior in engaging the mind of the reader.

Two primary distinctions can be made in summarizing Descartes methodology: (1) the distinction between the order of reasons and the order of subject-matter; and (2) the analysis/synthesis distinction. With respect to the first distinction, the great Continental rationalists are united. All adhere to the order of reasons, as we have described it above, rather than the order of subject-matter. Even though the rationalists disagree about how exactly to interpret the content of the order of reasons, their common commitment to following an order of reasons is a hallmark of their rationalism. Although there are points of convergence with respect to the second, analysis/synthesis distinction, there are also clear points of divergence, and this distinction can be useful in highlighting the range of approaches the rationalists adopt to mathematical methodology.

Of the great Continental rationalists, Spinoza is the most closely associated with mathematical method due to the striking presentation of his magnum opus, the Ethics, (as well as his presentation of Descartes Principles), in geometrical fashion. The fact that Spinoza is the only major rationalist to present his main work more geometrico might create the impression that he is the only philosopher to employ mathematical method in constructing and elaborating his philosophical system. This impression is mistaken, since both Descartes and Leibniz also apply mathematical method to philosophy. Nevertheless, there are differences between Spinozas employment of mathematical method and that of Descartes (and Leibniz). The most striking, of course, is the form of Spinozas Ethics. Each part begins with a series of definitions, axioms, and postulates and proceeds thence to deduce propositions, the demonstrations of which refer back to the definitions, axioms, postulates and previously demonstrated propositions on which they depend. Of course, this is just the method of presenting findings that Descartes in the Second Replies dubbed synthesis. For Descartes, analysis and synthesis differ only in pedagogical respects: whereas analysis is better for helping the reader discover the truth for herself, synthesis is better in compelling agreement.

There is some evidence that Spinozas motivations for employing synthesis were in part pedagogical. In Lodewijk Meyers preface to Spinozas Principles of Cartesian Philosophy, Meyer uses Descartes Second Replies distinction between analysis and synthesis to explain the motivation for the work. Meyer criticizes Descartes followers for being too uncritical in their enthusiasm for Descartes thought, and attributes this in part to the relative opacity of Descartes analytic mode of presentation. Thus, for Meyer, the motivation for presenting Descartes Principles in the synthetic manner is to make the proofs more transparent, and thereby leave less excuse for blind acceptance of Descartes conclusions. It is not clear to what extent Meyers explanation of the mode of presentation of Spinozas Principles of Cartesian Philosophy applies to Spinozas Ethics. In the first place, although Spinoza approved the preface, he did not author it himself. Secondly, while such an explanation seems especially suited to a work in which Spinozas chief goal was to present another philosophers thought in a different form, there is no reason to assume that it applies to the presentation of Spinozas own philosophy. Scholars have differed on how to interpret the geometrical form of Spinozas Ethics. However, it is generally accepted that Spinozas use of synthesis does not merely represent a pedagogical preference. There is reason to think that Spinozas methodology differs from that of Descartes in a somewhat deeper way.

There is another version of the analysis/synthesis distinction besides Descartes that was also influential in the 17th century, that is, Hobbes version of the distinction. Although there is little direct evidence that Spinoza was influenced by Hobbes version of the distinction, some scholars have claimed a connection, and, in any case, it is useful to view Spinozas methodology in light of the Hobbesian alternative.

Synthesis and analysis are not modes of demonstrating findings that have already been made, for Hobbes, as they are for Descartes, but rather complementary means of generating findings; in particular, they are forms of causal reasoning. For Hobbes, analysis is reasoning from effects to causes; synthesis is reasoning in the other direction, from causes to effects. For example, by analysis, we infer that geometrical objects are constructed via the motions of points and lines and surfaces. Once motion has been established as the principle of geometry, it is then possible, via synthesis, to construct the possible effects of motion, and thereby, to make new discoveries in geometry. According to the Hobbesian schema, then, synthesis is not merely a mode of presenting truths, but a means of generating and discovering truths. (For Hobbes method, see The English Works of Thomas Hobbes of Malmesbury, vol. 1, ch. 6.) There is reason to think that synthesis had this kind of significance for Spinoza, as well as a means of discovery, not merely presentation. Spinozas methodology, and, in particular, his theory of definitions, bear this out

Spinozas method begins with reflection on the nature of a given true idea. The given true idea serves as a standard by which the mind learns the distinction between true and false ideas, and also between the intellect and the imagination, and how to direct itself properly in the discovery of true ideas. The correct formulation of definitions emerges as the most important factor in directing the mind properly in the discovery of true ideas. To illustrate his conception of a good definition, Spinoza contrasts two definitions of a circle. On one definition, a circle is a figure in which all the lines from the center to the circumference are equal. On another, a circle is the figure described by the rotation of a line around one of its ends, which is fixed. For Spinoza, the second definition is superior. Whereas the first definition gives only a property of the circle, the second provides the cause from which all of the properties can be deduced. Hence, what makes a definition a good definition, for Spinoza, is its capacity to serve as a basis for the discovery of truths about the thing. The circle, of course, is just an example. For Spinoza, the method is perfected when it arrives at a true idea of the first cause of all things, that is, God. Only the method is perfected with a true idea of God, however, not the philosophy. The philosophy itself begins with a true idea of God, since the philosophy consists in deducing the consequences from a true idea of God. With this in mind, the definition of God is of paramount importance. In correspondence, Spinoza compares contrasting definitions of God, explaining that he chose the one which expresses the efficient cause from which all of the properties of God can be deduced.

In this light, it becomes clear that the geometrical presentation of Spinozas philosophy is not merely a pedagogic preference. The definitions that appear at the outset of the five parts of the Ethics do not serve merely to make explicit what might otherwise have remained only implicit in Descartes analytic mode of presentation. Rather, key definitions, such as the definition of God, are principles that underwrite the development of the system. As a result, Hobbes conception of the analysis/synthesis distinction throws an important light on Spinozas procedure. There is a movement of analysis in arriving at the causal definition of God from the preliminary given true idea. Then there is a movement of synthesis in deducing consequences from that causal definition. Of course, Descartes analysis/synthesis distinction still applies, since, after all, Spinozas system is presented in the synthetic manner in the Ethics. But the geometrical style of presentation is not merely a pedagogical device in Spinozas case. It is also a clue to the nature of his system.

Leibniz is openly critical of Descartes distinction between analysis and synthesis, writing, Those who think that the analytic presentation consists in revealing the origin of a discovery, the synthetic in keeping it concealed, are in error (L, 233). This comment is aimed at Descartes formulation of the distinction in the Second Replies. Leibniz is explicit about his adherence to the viewpoint that seems to be implied by Spinozas methodology: synthesis is itself a means of discovering truth no less than analysis, not merely a mode of presentation. Leibnizs understanding of analysis and synthesis is closer to the Hobbesian conception, which views analysis and synthesis as different directions of causal reasoning: from effects to causes (analysis) and from causes to effects (synthesis). Leibniz formulates the distinction in his own terms as follows:

Synthesis is achieved when we begin from principles and run through truths in good order, thus discovering certain progressions and setting up tables, or sometimes general formulas, in which the answers to emerging questions can later be discovered. Analysis goes back to the principles in order to solve the given problems only [] (L, 232)

Leibniz thus conceives synthesis and analysis in relation to principles.

Leibniz lays great stress on the importance of establishing the possibility of ideas, that is to say, establishing that ideas do not involve contradiction, and this applies a fortiori to first principles. For Leibniz, the Cartesian criterion of clear and distinct perception does not suffice for establishing the possibility of an idea. Leibniz is critical, in particular, of Descartes ontological argument on the grounds that Descartes neglects to demonstrate the possibility of the idea of a most perfect being on which the argument depends. It is possible to mistakenly assume that an idea is possible, when in reality it is contradictory. Leibniz gives the example of a wheel turning at the fastest possible rate. It might at first seem that this idea is legitimate, but if a spoke of the wheel were extended beyond the rim, the end of the spoke would move faster than a nail in the rim itself, revealing a contradiction in the original notion.

For Leibniz, there are two ways of establishing the possibility of an idea: by experience (a posteriori) and by reducing concepts via analysis down to a relation of identity (a priori). Leibniz credits mathematicians and geometers with pushing the practice of demonstrating what would otherwise normally be taken for granted the furthest. For example, in Meditations on Knowledge, Truth, and Ideas, Leibniz writes, That brilliant genius Pascal agrees entirely with these principles when he says, in his famous dissertation on the geometrical spirit [] that it is the task of the geometer to define all terms though ever so little obscure and to prove all truths though little doubtful (L, 294). Leibniz credits his own doctrine of the possibility of ideas with clarifying exactly what it means for something to be beyond doubt and obscurity.

Leibniz describes the result of the reduction of concepts to identity variously as follows: when the thing is resolved into simple primitive notions understood in themselves (L, 231); when every ingredient that enters into a distinct concept is itself known distinctly; when analysis is carried through to the end (L, 292). Since, for Leibniz, all true ideas can be reduced to simple identities, it is, in principle, possible to derive all truths via a movement of synthesis from such simple identities in the way that mathematicians produce systems of knowledge on the basis of their basic definitions and axioms. This kind of a priori knowledge of the world is restricted to God, however. According to Leibniz, it is only possible for our finite minds to have this kind of knowledge which Leibniz calls intuitive or adequate in the case of things which do not depend on experience, or what Leibniz also calls truths of reason, which include abstract logical and metaphysical truths, and mathematical propositions. In the case of truths of fact, by contrast, with the exception of immediately graspable facts of experience, such as, I think, and Various things are thought by me, we are restricted to formulating hypotheses to explain the phenomena of sensory experience, and such knowledge of the world can, for us, only ever achieve the status of hypothesis, though our hypothetical knowledge can be continually improved and refined. (See Section 5, c, below for a discussion of hypotheses in Leibniz.)

Leibniz is in line with his rationalist predecessors in emphasizing the importance of proper order in philosophizing. Leibnizs emphasis on establishing the possibility of ideas prior to using them in demonstrating propositions could be understood as a refinement of the geometrical order that Descartes established over against the order of subject-matter. Leibniz emphasizes order in another connection vis–vis Locke. As Leibniz makes clear in his New Essays, one of the clearest points of disagreement between him and Locke is on the question of innate ideas. In preliminary comments that Leibniz drew up upon first reading Lockes Essay, and which he sent to Locke via Burnett, Leibniz makes the following point regarding philosophical order:

Concerning the question whether there are ideas and truths born with us, I do not find it absolutely necessary for the beginnings, nor for the practice of the art of thinking, to answer it; whether they all come to us from outside, or they come from within us, we will reason correctly provided that we keep in mind what I said above, and that we proceed with order and without prejudice. The question of the origin of our ideas and of our maxims is not preliminary in philosophy, and it is necessary to have made great progress in order to resolve it. (Philosophische Schriften, vol. 5, pp. 15-16)

Leibnizs allusion to what he said above refers to remarks regarding the establishment of the possibility of ideas via experience and the principle of identity. This passage makes it clear that, from Leibnizs point of view, the order in which Locke philosophizes is quite misguided, since Locke begins with a question that should only be addressed after great progress has already been made, particularly with respect to the criteria for distinguishing between true and false ideas, and for establishing legitimate philosophical principles. Empiricists generally put much less emphasis on the order of philosophizing, since they do not aim to reason from first principles grasped a priori.

A fundamental tenet of rationalism perhaps the fundamental tenet is that the world is intelligible. The intelligibility tenet means that everything that happens in the world happens in an orderly, lawful, rational manner, and that the mind, in principle, if not always in practice, is able to reproduce the interconnections of things in thought provided that it adheres to certain rules of right reasoning. The intelligibility of the world is sometimes couched in terms of a denial of brute facts, where a brute fact is something that just is the case, that is, something that obtains without any reason or explanation (even in principle). Many of the a priori principles associated with rationalism can be understood either as versions or implications of the principle of intelligibility. As such, the principle of intelligibility functions as a basic principle of rationalism. It appears under various guises in the great rationalist systems and is used to generate contrasting philosophical systems. Indeed, one of the chief criticisms of rationalism is the fact that its principles can consistently be used to generate contradictory conclusions and systems of thought. The clearest and best known statement of the intelligibility of the world is Leibnizs principle of sufficient reason. Some scholars have recently emphasized this principle as the key to understanding rationalism (see Della Rocca 2008, chapter 1).

The intelligibility principle raises some classic philosophical problems. Chief among these is a problem of question-begging or circularity. The task of proving that the world is intelligible seems to have to rely on some of the very principles of reasoning in question. In the 17th century, discussion of this fundamental problem centered around the so-called Cartesian circle. The problem is still debated by scholars of 17th century thought today. The viability of the rationalist enterprise seems to depend, at least in part, on a satisfactory answer to this problem.

The most important rational principle in Descartes philosophy, the principle which does a great deal of the work in generating its details, is the principle according to which whatever is clearly and distinctly perceived to be true is true. This principle means that if we can form any clear and distinct ideas, then we will be able to trust that they accurately represent their objects, and give us certain knowledge of reality. Descartes clear and distinct ideas doctrine is central to his conception of the worlds intelligibility, and indeed, it is central to the rationalists conception of the worlds intelligibility more broadly. Although Spinoza and Leibniz both work to refine understanding of what it is to have clear and distinct ideas, they both subscribe to the view that the mind, when directed properly, is able to accurately represent certain basic features of reality, such as the nature of substance.

For Descartes, it cannot be taken for granted from the outset that what we clearly and distinctly perceive to be true is in fact true. It is possible to entertain the doubt that an all-powerful deceiving being fashioned the mind so that it is deceived even in those things it perceives clearly and distinctly. Nevertheless, it is only possible to entertain this doubt when we are not having clear and distinct perceptions. When we are perceiving things clearly and distinctly, their truth is undeniable. Moreover, we can use our capacity for clear and distinct perceptions to demonstrate that the mind was not fashioned by an all-powerful deceiving being, but rather by an all-powerful benevolent being who would not fashion us so as to be deceived even when using our minds properly. Having proved the existence of an all-powerful benevolent being qua creator of our minds, we can no longer entertain any doubts regarding our clear and distinct ideas even when we are not presently engaged in clear and distinct perceptions.

Descartes legitimation of clear and distinct perception via his proof of a benevolent God raises notorious interpretive challenges. Scholars disagree about how to resolve the problem of the Cartesian circle. However, there is general consensus that Descartes procedure is not, in fact, guilty of vicious, logical circularity. In order for Descartes procedure to avoid circularity, it is generally agreed that in some sense clear and distinct ideas need already to be legitimate before the proof of Gods existence. It is only in another sense that Gods existence legitimates their truth. Scholars disagree on how exactly to understand those different senses, but they generally agree that there is some sense at least in which clear and distinct ideas are self-legitimating, or, otherwise, not in need of legitimation.

That some ideas provide a basic standard of truth is a fundamental tenet of rationalism, and undergirds all the other rationalist principles at work in the construction of rationalist systems of philosophy. For the rationalists, if it cannot be taken for granted in at least some sense from the outset that the mind is capable of discerning the difference between truth and falsehood, then one never gets beyond skepticism.

The Continental rationalists deploy the principle of intelligibility and subordinate rational principles derived from it in generating much of the content of their respective philosophical systems. In no aspect of their systems is the application of rational principles to the generation of philosophical content more evident and more clearly illustrative of contrasting interpretations of these principles than in that for which the Continental rationalists are arguably best known: substance metaphysics.

Descartes deploys his clear and distinct ideas doctrine in justifying his most well-known metaphysical position: substance dualism. The first step in Descartes demonstration of mind-body dualism, or, in his terminology, of a real distinction (that is, a distinction between two substances) between mind and body is to show that while it is possible to doubt that one has a body, it is not possible to doubt that one is thinking. As Descartes makes clear in the Principles of Philosophy, one of the chief upshots of his famous cogito argument is the discovery of the distinction between a thinking thing and a corporeal thing. The impossibility of doubting ones existence is not the impossibility of doubting that one is a human being with a body with arms and legs and a head. It is the impossibility of doubting, rather, that one doubts, perceives, dreams, imagines, understands, wills, denies, and other modalities that Descartes attributes to the thinking thing. It is possible to think of oneself as a thing that thinks, and to recognize that it is impossible to doubt that one thinks, while continuing to doubt that one has a body with arms and legs and a head. So, the cogito drives a preliminary wedge between mind and body.

At this stage of the argument, however, Descartes has simply established that it is possible to conceive of himself as a thinking thing without conceiving of himself as a corporeal thing. It remains possible that, in fact, the thinking thing is identical with a corporeal thing, in other words, that thought is somehow something a body can do; Descartes has yet to establish that the epistemological distinction between his knowledge of his mind and his knowledge of body that results from the hyperbolic doubt translates to a metaphysical or ontological distinction between mind and body. The move from the epistemological distinction to the ontological distinction proceeds via the doctrine of clear and distinct ideas. Having established that whatever he clearly and distinctly perceives is true, Descartes is in a position to affirm the real distinction between mind and body.

In this life, it is never possible to clearly and distinctly perceive a mind actually separate from a body, at least in the case of finite, created minds, because minds and bodies are intimately unified in the composite human being. So Descartes cannot base his proof for the real distinction of mind and body on the clear and distinct perception that mind and body are in fact independently existing things. Rather, Descartes argument is based on the joint claims that (1) it is possible to have a clear and distinct idea of thought apart from extension and vice versa; and (2) whatever we can clearly and distinctly understand is capable of being created by God exactly as we clearly and distinctly understand it. Thus, the fact that we can clearly and distinctly understand thought apart from extension and vice versa entails that thinking things and extended things are really distinct (in the sense that they are distinct substances separable by God).

The foregoing argument relies on certain background assumptions which it is now necessary to explain, in particular, Descartes conception of substance. In the Principles, Descartes defines substance as a thing which exists in such a way as to depend on no other thing for its existence (CSM I, 210). Properly speaking, only God can be understood to depend on no other thing, and so only God is a substance in the absolute sense. Nevertheless, Descartes allows that, in a relative sense, created things can count as substances too. A created thing is a substance if the only thing it relies upon for its existence is the ordinary concurrence of God (ibid.). Only mind and body qualify as substances in this secondary sense. Everything else is a modification or property of minds and bodies. A second point is that, for Descartes, we do not have a direct knowledge of substance; rather, we come to know substance by virtue of its attributes. Thought and extension are the attributes or properties in virtue of which we come to know thinking and corporeal substance, or mind and body. This point relies on the application of a key rational principle, to wit, nothingness has no properties. For Descartes, there cannot simply be the properties of thinking and extension without these properties having something in which to inhere. Thinking and extension are not just any properties; Descartes calls them principal attributes because they constitute the nature of their respective substances. Other, non-essential properties, cannot be understood without the principal attribute, but the principal attribute can be understood without any of the non-essential properties. For example, motion cannot be understood without extension, but extension can be understood without motion.

Descartes conception of mind and body as distinct substances includes some interesting corollaries which result from a characteristic application of rational principles and account for some characteristic doctrinal differences between Descartes and empiricist philosophers. One consequence of Descartes conception of the mind as a substance whose principal attribute is thought is that the mind must always be thinking. Since, for Descartes, thinking is something of which the thinker is necessarily aware, Descartes commitment to thought as an essential, and therefore, inseparable, property of the mind raises some awkward difficulties. Arnauld, for example, raises one such difficulty in his Objections to Descartes Meditations: presumably there is much going on in the mind of an infant in its mothers womb of which the infant is not aware. In response to this objection, and also in response to another obvious problem, that is, that of dreamless sleep, Descartes insists on a distinction between being aware of or conscious of our thoughts at the time we are thinking them, and remembering them afterwards (CSMK III, 357). The infant is, in fact, aware of its thinking in the mothers womb, but it is aware only of very confused sensory thoughts of pain and pleasure and heat (not, as Descartes points out, metaphysical matters (CSMK III, 189)) which it does not remember afterwards. Similarly, the mind is always thinking even in the most dreamless sleep, it is just that the mind often immediately forgets much of what it had been aware.

Descartes commitment to embracing the implications however counter-intuitive of his substance-attribute metaphysics, puts him at odds with, for instance, Locke, who mocks the Cartesian doctrine of the always-thinking soul in his An Essay Concerning Human Understanding. For Locke, the question whether the soul is always thinking or not must be decided by experience and not, as Locke says, merely by hypothesis (An Essay Concerning Human Understanding, Book II, Chapter 1). The evidence of dreamless sleep makes it obvious, for Locke, that the soul is not always thinking. Because Locke ties personal identity to memory, if the soul were to think while asleep without knowing it, the sleeping man and the waking man would be two different persons.

Descartes commitment to the always-thinking mind is a consequence of his commitment to a more basic rational principle. In establishing his conception of thinking substance, Descartes reasons from the attribute of thinking to the substance of thinking on the grounds that nothing has no properties. In this case, he reasons in the other direction, from the substance of thinking, that is, the mind, to the property of thinking on the converse grounds that something must have properties, and the properties it must have are the properties that make it what it is; in the case of the mind, that property is thought. (Leibniz found a way to maintain the integrity of the rational principle without contradicting experience: admit that thinking need not be conscious. This way the mind can still think in a dreamless sleep, and so avoid being without any properties, without any problem about the recollection of awareness.)

Another consequence of Descartes substance metaphysics concerns corporeal substance. For Descartes, we do not know corporeal substance directly, but rather through a grasp of its principal attribute, extension. Extension qua property requires a substance in which to inhere because of the rational principle, nothing has no properties. This rational principle leads to another characteristic Cartesian position regarding the material world: the denial of a vacuum. Descartes denies that space can be empty or void. Space has the property of being extended in length, breadth, and depth, and such properties require a substance in which to inhere. Thus, nothing, that is, a void or vacuum, is not able to have such properties because of the rational principle, nothing has no properties. This means that all space is filled with substance, even if it is imperceptible. Once again, Descartes answers a debated philosophical question on the basis of a rational principle.

If Descartes is known for his dualism, Spinoza, of course, is known for monism the doctrine that there is only one substance. Spinozas argument for substance monism (laid out in the first fifteen propositions of the Ethics) has no essential basis in sensory experience; it proceeds through rational argumentation and the deployment of rational principles; although Spinoza provides one a posteriori argument for Gods existence, he makes clear that he presents it only because it is easier to grasp than the a priori arguments, and not because it is in any way necessary.

The crucial step in the argument for substance monism comes in Ethics 1p5: In Nature there cannot be two or more substances of the same nature or attribute. It is at this proposition that Descartes (and Leibniz, and many others) would part ways with Spinoza. The most striking and controversial implication of this proposition, at least from a Cartesian perspective, is that human minds cannot qualify as substances, since human minds all share the same nature or attribute, that is, thought. In Spinozas philosophy, human minds are actually themselves properties Spinoza calls them modes of a more basic, infinite substance.

The argument for 1p5 works as follows. If there were two or more distinct substances, there would have to be some way to distinguish between them. There are two possible distinctions to be made: either by a difference in their affections or by a difference in their attributes. For Spinoza, a substance is something which exists in itself and can be conceived through itself; an attribute is what the intellect perceives of a substance, as constituting its essence (Ethics 1d4). Spinozas conception of attributes is a matter of longstanding scholarly debate, but for present purposes, we can think of it along Cartesian lines. For Descartes, substance is always grasped through a principal property, which is the nature or essence of the substance. Spinoza agrees that an attribute is that through which the mind conceives the nature or essence of substance. With this in mind, if a distinction between two substances were to be made on the basis of a difference in attributes, then there would not be two substances of the same attribute as the proposition indicates. This means that if there were two substances of the same attribute, it would be necessary to distinguish between them on the basis of a difference in modes or affections.

Spinoza conceives of an affection or mode as something which exists in another and needs to be conceived through another. Given this conception of affections, it is impossible, for Spinoza, to distinguish between two substances on the basis of a difference in affections. Doing so would be somewhat akin to affirming that there are two apples on the basis of a difference between two colors, when one apple can quite possibly have a red part and a green part. As color differences do not per se determine differences between apples, in a similar way, modal differences cannot determine a difference between substances you could just be dealing with one substance bearing multiple different affections. It is notable that in 1p5, Spinoza uses virtually the same substance-attribute schema as Descartes to deny a fundamental feature of Descartes system.

Having established 1p5, the next major step in Spinozas argument for substance monism is to establish the necessary existence and infinity of substance. For Spinoza, if things have nothing in common with each other, one cannot be the cause of the other. This thesis depends upon assumptions that lie at the heart of Spinozas rationalism. Something that has nothing in common with another thing cannot be the cause of the other thing because things that have nothing in common with one another cannot be understood through one another (Ethics 1a5). But, for Spinoza, effects should be able to be understood through causes. Indeed, what it is to understand something, for Spinoza, is to understand its cause. The order of knowledge, provided that the knowledge is genuine, or, as Spinoza says, adequate, must map onto the order of being, and vice versa. Thus, Spinozas claim that if things have nothing in common with one another, one cannot be the cause of the other, is an expression of Spinozas fundamental, rationalist commitment to the intelligibility of the world. Given this assumption, and given the fact that no two substances have anything in common with one another, since no two substances share the same nature or attribute, it follows that if a substance is to exist, it must exist as causa sui (self-caused); in other words, it must pertain to the essence of substance to exist. Moreover, Spinoza thinks that since there is nothing that has anything in common with a given substance, there is therefore nothing to limit the nature of a given substance, and so every substance will necessarily be infinite. This assertion depends on another deep-seated assumption of Spinozas philosophy: nothing limits itself, but everything by virtue of its very nature affirms its own nature and existence as much as possible.

At this stage, Spinoza has argued that substances of a single attribute exist necessarily and are necessarily infinite. The last major stage of the argument for substance monism is the transition from multiple substances of a single attribute to only one substance of infinite attributes. Scholars have expressed varying degrees of satisfaction with the lucidity of this transition. It seems to work as follows. It is possible to attribute many attributes to one substance. The more reality or being each thing has, the more attributes belong to it. Therefore, an absolutely infinite being is a being that consists of infinite attributes. Spinoza calls an absolutely infinite being or substance consisting of infinite attributes God. Spinoza gives four distinct arguments for Gods existence in Ethics 1p11. The first is commonly interpreted as Spinozas version of an ontological argument. It refers back to 1p7 where Spinoza proved that it pertains to the essence of substance to exist. The second argument is relevant to present purposes, since it turns on Spinozas version of the principle of sufficient reason: For each thing there must be assigned a cause, or reason, both for its existence and for its nonexistence (Ethics 1p11dem). But there can be no reason for Gods nonexistence for the same reasons that all substances are necessarily infinite: there is nothing outside of God that is able to limit Him, and nothing limits itself. Once again, Spinozas argument rests upon his assumption that things by nature affirm their own existence. The third argument is a posteriori, and the fourth pivots like the second on the assumption that things by nature affirm their own existence.

Having proven that a being consisting of infinite attributes exists, Spinozas argument for substance monism is nearly complete. It remains only to point out that no substance besides God can exist, because if it did, it would have to share at least one of Gods infinite attributes, which, by 1p5, is impossible. Everything that exists, then, is either an attribute or an affection of God.

Leibnizs universe consists of an infinity of monads or simple substances, and God. For Leibniz, the universe must be composed of monads or simple substances. His justification for this claim is relatively straightforward. There must be simples, because there are compounds, and compounds are just collections of simples. To be simple, for Leibniz, means to be without parts, and thus to be indivisible. For Leibniz, the simples or monads are the true atoms of nature (L, 643). However, material atoms are contrary to reason (L, 456). Manifold a priori considerations lead Leibniz to reject material atoms. In the first place, the notion of a material atom is contradictory in Leibnizs view. Matter is extended, and that which is extended is divisible into parts. The very notion of an atom, however, is the notion of something indivisible, lacking parts.

From a different perspective, Leibnizs dynamical investigations provide another argument against material atoms. Absolute rigidity is included in the notion of a material atom, since any elasticity in the atom could only be accounted for on the basis of parts within the atom shifting their position with respect to each other, which is contrary to the notion of a partless atom. According to Leibnizs analysis of impact, however, absolute rigidity is shown not to make sense. Consider the rebound of one atom as a result of its collision with another. If the atoms were absolutely rigid, the change in motion resulting from the collision would have to happen instantaneously, or, as Leibniz says, through a leap or in a moment (L, 446). The atom would change from initial motion to rest to rebounded motion without passing through any intermediary degrees of motion. Since the body must pass through all the intermediary degrees of motion in transitioning from one state of motion to another, it must not be absolutely rigid, but rather elastic; the analysis of the parts of the body must, in correlation with the degree of motion, proceed to infinity. Leibnizs dynamical argument against material atoms turns on what he calls the law of continuity, an a priori principle according to which no change occurs through a leap.

The true unities, or true atoms of nature, therefore, cannot be material; they must be spiritual or metaphysical substances akin to souls. Since Leibnizs spiritual substances, or monads, are absolutely simple, without parts, they admit neither of dissolution nor composition. Moreover, there can be no interaction between monads, monads cannot receive impressions or undergo alterations by means of being affected from the outside, since, in Leibnizs famous phrase from the Monadology, monads have no windows (L, 643). Monads must, however, have qualities, otherwise there would be no way to explain the changes we see in things and the diversity of nature. Indeed, following from Leibnizs principle of the identity of indiscernibles, no two monads can be exactly alike, since each monad stands in a unique relation to the rest, and, for Leibniz, each monads relation to the rest is a distinctive feature of its nature. The way in which, for Leibniz, monads can have qualities while remaining simple, or in other words, the only way there can be multitude in simplicity is if monads are characterized and distinguished by means of their perceptions. Leibnizs universe, in summary, consists in monads, simple spiritual substances, characterized and distinguished from one another by a unique series of perceptions determined by each monads unique relationship vis–vis the others.

Of the great rationalists, Leibniz is the most explicit about the principles of reasoning that govern his thought. Leibniz singles out two, in particular, as the most fundamental rational principles of his philosophy: the principle of contradiction and the principle of sufficient reason. According to the principle of contradiction, whatever involves a contradiction is false. According to the principle of sufficient reason, there is no fact or true proposition without there being a sufficient reason for its being so and not otherwise (L, 646). Corresponding to these two principles of reasoning are two kinds of truths: truths of reasoning and truths of fact. For Leibniz, truths of reasoning are necessary, and their opposite is impossible. Truths of fact, by contrast, are contingent, and their opposite is possible. Truths of reasoning are by most commentators associated with the principle of contradiction because they can be reduced via analysis to a relation between two primitive ideas, whose identity is intuitively evident. Thus, it is possible to grasp why it is impossible for truths of reasoning to be otherwise. However, this kind of resolution is only possible in the case of abstract propositions, such as the propositions of mathematics (see Section 3, c, above). Contingent truths, or truths of fact, by contrast, such as Caesar crossed the Rubicon, to use the example Leibniz gives in the Discourse on Metaphysics, are infinitely complicated. Although, for Leibniz, every predicate is contained in its subject, to reduce the relationship between Caesars notion and his action of crossing the Rubicon would require an infinite analysis impossible for finite minds. Caesar crossed the Rubicon is a contingent proposition, because there is another possible world in which Caesar did not cross the Rubicon. To understand the reason for Caesars crossing, then, entails understanding why this world exists rather than any other possible world. It is for this reason that contingent truths are associated with the principle of sufficient reason. Although the opposite of truths of fact is possible, there is nevertheless a sufficient reason why the fact is so and not otherwise, even though this reason cannot be known by finite minds.

Truths of fact, then, need to be explained; there must be a sufficient reason for them. However, according to Leibniz, a sufficient reason for existence cannot be found merely in any one individual thing or even in the whole aggregate and series of things (L, 486). That is to say, the sufficient reason for any given contingent fact cannot be found within the world of which it is a part. The sufficient reason must explain why this world exists rather than another possible world, and this reason must lie outside the world itself. For Leibniz, the ultimate reason for things must be contained in a necessary substance that creates the world, that is, God. But if the existence of God is to ground the series of contingent facts that make up the world, there must be a sufficient reason why God created this world rather than any of the other infinite possible worlds contained in his understanding. As a perfect being, God would only have chosen to bring this world into existence rather than any other because it is the best of all possible worlds. Gods choice, therefore, is governed by the principle of fitness, or what Leibniz also calls the principle of the best (L, 647). The best world, according to Leibniz, is the one which maximizes perfection; and the most perfect world is the one which balances the greatest possible variety with the greatest possible order. God achieves maximal perfection in the world through what Leibniz calls the pre-established harmony. Although the world is made up of an infinity of monads with no direct interaction with one another, God harmonizes the perceptions of each monad with the perceptions of every other monad, such that each monad represents a unique perspective on the rest of the universe according to its position vis–vis the others.

According to Leibnizs philosophy, in the case of all true propositions, the predicate is contained in the subject. This is often known as the predicate-in-notion principle. The relationship between predicate and subject can only be reduced to an identity relation in the case of truths of reason, whereas in the case of truths of fact, the reduction requires an infinite analysis. Nevertheless, in both cases, it is possible in principle (which is to say, for an infinite intellect) to know everything that will ever happen to an individual substance, and even everything that will happen in the world of an individual substance on the basis of an examination of the individual substances notion, since each substance is an expression of the entire world. Leibnizs predicate-in-notion principle therefore unifies both of his two great principles of reasoning the principle of contradiction and the principle of sufficient reason since the relation between predicate and subject is either such that it is impossible for it to be otherwise or such that there is a sufficient reason why it is as it is and not otherwise. Moreover, it represents a particularly robust expression of the principle of intelligibility at the very heart of Leibnizs system. There is a reason why everything is as it is, whether that reason is subject to finite or only to infinite analysis.

(See also: 17th Century Theories of Substance.)

Rationalism is often criticized for placing too much confidence in the ability of reason alone to know the world. The extent to which one finds this criticism justified depends largely on ones view of reason. For Hume, for instance, knowledge of the world of matters of fact is gained exclusively through experience; reason is merely a faculty for comparing ideas gained through experience; it is thus parasitic upon experience, and has no claim whatsoever to grasp anything about the world itself, let alone any special claim. For Kant, reason is a mental faculty with an inherent tendency to transgress the bounds of possible experience in an effort to grasp the metaphysical foundations of the phenomenal realm. Since knowledge of the world is limited to objects of possible experience, for Kant, reason, with its delusions of grasping reality beyond those limits, must be subject to critique.

Sometimes rationalism is charged with neglecting or undervaluing experience, and with embarrassingly having no means of accounting for the tremendous success of the experimental sciences. While the criticism of the confidence placed in reason may be defensible given a certain conception of reason (which may or may not itself be ultimately defensible), the latter charge of neglecting experience is not; more often than not it is the product of a false caricature of rationalism

Descartes and Leibniz were the leading mathematicians of their day, and stood at the forefront of science. While Spinoza distinguished himself more as a political thinker, and as an interpreter of scripture (albeit a notorious one) than as a mathematician, Spinoza too performed experiments, kept abreast of the leading science of the day, and was renowned as an expert craftsman of lenses. Far from neglecting experience, the great rationalists had, in general, a sophisticated understanding of the role of experience and, indeed, of experiment, in the acquisition and development of knowledge. The fact that the rationalists held that experience and experiment cannot serve as foundations for knowledge, but must be fitted within, and interpreted in light of, a rational epistemic framework, should not be confused with a neglect of experience and experiment.

One of the stated purposes of Descartes Meditations, and, in particular, the hyperbolic doubts with which it commences, is to reveal to the mind of the reader the limitations of its reliance on the senses, which Descartes regards as an inadequate foundation for knowledge. By leading the mind away from the senses, which often deceive, and which yield only confused ideas, Descartes prepares the reader to discover the clear and distinct perceptions of the pure intellect, which provide a proper foundation for genuine knowledge. Nevertheless, empirical observations and experimentation clearly had an important role to play in Descartes natural philosophy, as evidenced by his own private empirical and experimental research, especially in optics and anatomy, and by his explicit statements in several writings on the role and importance of observation and experiment.

In Part 6 of the Discourse on the Method, Descartes makes an open plea for assistance both financial and otherwise in making systematic empirical observations and conducting experiments. Also in Discourse Part 6, Descartes lays out his program for developing knowledge of nature. It begins with the discovery of certain seeds of truth implanted naturally in our souls (CSM I, 144). From them, Descartes seeks to derive the first principles and causes of everything. Descartes Meditations illustrates these first stages of the program. By seeds of truth Descartes has in mind certain intuitions, including the ideas of thinking, and extension, and, in particular, of God. On the basis of clearly and distinctly perceiving the distinction between what belongs properly to extension (figure, position, motion) and what does not (colors, sounds, smells, and so forth), Descartes discovers the principles of physics, including the laws of motion. From these principles, it is possible to deduce many particular ways in which the details of the world might be, only a small fraction of which represent the way the world actually is. It is as a result of the distance, as it were, between physical principles and laws of nature, on one hand, and the particular details of the world, on the other, that, for Descartes, observations and experiments become necessary.

Descartes is ambivalent about the relationship between physical principles and particulars, and about the role that observation and experiment play in mediating this relationship. On the one hand, Descartes expresses commitment to the ideal of a science deduced with certainty from intuitively grasped first principles. Because of the great variety of mutually incompatible consequences that can be derived from physical principles, observation and experiment are required even in the ideal deductive science to discriminate between actual consequences and merely possible ones. According to the ideal of deductive science, however, observation and experiment should be used only to facilitate the deduction of effects from first causes, and not as a basis for an inference to possible explanations of natural phenomena, as Descartes makes clear at one point his Principles of Philosophy (CSM I, 249). If the explanations were only possible, or hypothetical, the science could not lay claim to certainty per the deductive ideal, but merely to probability.

On the other hand, Descartes states explicitly at another point in the Principles of Philosophy that the explanations provided of such phenomena as the motion of celestial bodies and the nature of the earths elements should be regarded merely as hypotheses arrived at on the basis of a posteriori reasoning (CSM I, 255); while Descartes says that such hypotheses must agree with observation and facilitate predictions, they need not in fact reflect the actual causes of phenomena. Descartes appears to concede, albeit reluctantly, that when it comes to explaining particular phenomena, hypothetical explanations and moral certainty (that is, mere probability) are all that can be hoped for.

Scholars have offered a range of explanations for the inconsistency in Descartes writings on the question of the relation between first principles and particulars. It has been suggested that the inconsistency within the Principles of Philosophy reflects different stages of its composition (see Garber 1978). However the inconsistency might be explained, it is clear that Descartes did not take it for granted that the ideal of a deductive science of nature could be realized. Moreover, whether or not Descartes ultimately believed the ideal of deductive science was realizable, he was unambiguous on the importance of observation and experiment in bridging the distance between physical principles and particular phenomena. (For further discussion, see Ren Descartes: Scientific Method.)

The one work that Spinoza published under his own name in his lifetime was his geometrical reworking of Descartes Principles of Philosophy. In Spinozas presentation of the opening sections of Part 3 of Descartes Principles, Spinoza puts a strong emphasis on the hypothetical nature of the explanations of natural phenomena in Part 3. Given the hesitance and ambivalence with which Descartes concedes the hypothetical nature of his explanations in his Principles, Spinozas unequivocal insistence on hypotheses is striking. Elsewhere Spinoza endorses hypotheses more directly. In the Treatise on the Emendation of the Intellect, Spinoza describes forming the concept of a sphere by affirming the rotation of a semicircle in thought. He points out that this idea is a true idea of a sphere even if no sphere has ever been produced this way in nature (The Collected Works of Spinoza, Vol. 1, p. 32). Spinozas view of hypotheses relates to his conception of good definitions (see Section 3, b, above). If the cause through which one conceives something allows for the deduction of all possible effects, then the cause is an adequate one, and there is no need to fear a false hypothesis. Spinoza appears to differ from Descartes in thinking that the formation of hypotheses, if done properly, is consistent with deductive certainty, and not tantamount to mere probability or moral certainty.

Again in the Treatise on the Emendation of the Intellect, Spinoza speaks in Baconian fashion of identifying aids that can assist in the use of the senses and in conducting orderly experiments. Unfortunately, Spinozas comments regarding aids are very unclear. This is perhaps explained by the fact that they appear in a work that Spinoza never finished. Nevertheless, it does seem clear that although Spinoza, like Descartes, emphasized the importance of discovering proper principles from which to deduce knowledge of everything else, he was no less aware than Descartes of the need to proceed via observation and experiment in descending from such principles to particulars. At the same time, given his analysis of the inadequacy of sensory images, the collection of empirical data must be governed by rules and rational guidelines the details of which it does not seem that Spinoza ever worked out.

A valuable perspective on Spinozas attitude toward experimentation is provided by Letter 6, which Spinoza wrote to Oldenburg with comments on Robert Boyles experimental research. Among other matters, at issue is Boyles redintegration (or reconstitution) of niter (potassium nitrate). By heating niter with a burning coal, Boyle separated the niter into a fixed part and a volatile part; he then proceeded to distill the volatile part, and recombine it with the fixed part, thereby redintegrating the niter. Boyles aim was to show that the nature of niter is not determined by a Scholastic substantial form, but rather by the composition of parts, whose secondary qualities (color, taste, smell, and so forth) are determined by primary qualities (size, position, motion, and so forth). While taking no issue with Boyles attempt to undermine the Scholastic analysis of physical natures, Spinoza criticized Boyles interpretation of the experiment, arguing that the fixed niter was merely an impurity left over, and that there was no difference between the niter and the volatile part other than a difference of state.

Two things stand out from Spinozas comments on Boyle. On the one hand, Spinoza exhibits a degree of impatience with Boyles experiments, charging some of them with superfluity on the grounds either that what they show is evident on the basis of reason alone, or that previous philosophers have already sufficiently demonstrated them experimentally. In addition, Spinozas own interpretation of Boyles experiment is primarily based in a rather speculative, Cartesian account of the mechanical constitution of niter (as Boyle himself points out in response to Spinoza). On the other hand, Spinoza appears eager to show his own fluency with experimental practice, describing no fewer than three different experiments of his own invention to support his interpretation of the redintegration. What Spinoza is critical of is not so much Boyles use of experiment per se as his relative neglect of relevant rational considerations. For instance, Spinoza at one point criticizes Boyle for trying to show that secondary qualities depend on primary qualities on experimental grounds. Spinoza thought the proposition needed to be demonstrated on rational grounds. While Spinoza acknowledges the importance and necessity of observation and experiment, his emphasis and focus is on the rational framework needed for making sense of experimental findings, without which the results are confused and misleading.

In principle, Leibniz thinks it is not impossible to discover the interior constitution of bodies a priori on the basis of a knowledge of God and the principle of the best according to which He creates the world. Leibniz sometimes remarks that angels could explain to us the intelligible causes through which all things come about, but he seems conflicted over whether such understanding is actually possible for human beings. Leibniz seems to think that while the a priori pathway should be pursued in this life by the brightest minds in any case, its perfection will only be possible in the afterlife. The obstacle to an a priori conception of things is the complexity of sensible effects. In this life, then, knowledge of nature cannot be purely a priori, but depends on observation and experimentation in conjunction with reason

Apart from perception, we have clear and distinct ideas only of magnitude, figure, motion, and other such quantifiable attributes (primary qualities). The goal of all empirical research must be to resolve phenomena (including secondary qualities) into such distinctly perceived, quantifiable notions. For example, heat is explained in terms of some particular motion of air or some other fluid. Only in this way can the epistemic ideal be achieved of understanding how phenomena follow from their causes in the same way that we know how the hammer stroke after a period of time follows from the workings of a clock (L, 173). To this end, experiments must be carried out to indicate possible relationships between secondary qualities and primary qualities, and to provide a basis for the formulation of hypotheses to explain the phenomena.

Nevertheless, there is an inherent limitation to this procedure. Leibniz explains that if there were people who had no direct experience of heat, for instance, even if someone were to explain to them the precise mechanical cause of heat, they would still not be able to know the sensation of heat, because they would still not distinctly grasp the connection between bodily motion and perception (L, 285). Leibniz seems to think that human beings will never be able to bridge the explanatory gap between sensations and mechanical causes. There will always be an irreducibly confused aspect of sensible ideas, even if they can be associated with a high degree of sophistication with distinctly perceivable, quantifiable notions. However, this limitation does not mean, for Leibniz, that there is any futility in human efforts to understand the world scientifically. In the first place, experimental knowledge of the composition of things is tremendously useful in practice, even if the composition is not distinctly perceived in all its parts. As Leibniz points out, the architect who uses stones to erect a cathedral need not possess a distinct knowledge of the bits of earth interposed between the stones (L, 175). Secondly, even if our understanding of the causes of sensible effects must remain forever hypothetical, the hypotheses themselves can be more or less refined, and it is proper experimentation that assists in their refinement.

When citing the works of Descartes, the three volume English translation by Cottingham, Stoothoff, Murdoch, and Kenny was used. For the original language, the edition by Adam and Tannery was consulted.

When citing Spinozas Ethics, the translation by Curley in A Spinoza Reader was used. The following system of abbreviation was used when citing passages from the Ethics: the first number designates the part of the Ethics (1-5); then, p is for proposition, d for definition, a for axiom, dem for demonstration, c for corollary, and s for scholium. So, 1p17s refers to the scholium of the seventeenth proposition of the first part of the Ethics. For the original language, the edition by Gebhardt was consulted.

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Rationalism, Continental | Internet Encyclopedia of Philosophy

Rationalism vs. Empiricism: Similarities & Differences …

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Rationalism vs. Empiricism: Similarities & Differences …

Rationalism – Wikipedia

In philosophy, rationalism is the epistemological view that “regards reason as the chief source and test of knowledge”[3] or “any view appealing to reason as a source of knowledge or justification”.[4] More formally, rationalism is defined as a methodology or a theory “in which the criterion of the truth is not sensory but intellectual and deductive”.[5]

In an old controversy, rationalism was opposed to empiricism, where the rationalists believed that reality has an intrinsically logical structure. Because of this, the rationalists argued that certain truths exist and that the intellect can directly grasp these truths. That is to say, rationalists asserted that certain rational principles exist in logic, mathematics, ethics, and metaphysics that are so fundamentally true that denying them causes one to fall into contradiction. The rationalists had such a high confidence in reason that empirical proof and physical evidence were regarded as unnecessary to ascertain certain truths in other words, “there are significant ways in which our concepts and knowledge are gained independently of sense experience”.[6]

Different degrees of emphasis on this method or theory lead to a range of rationalist standpoints, from the moderate position “that reason has precedence over other ways of acquiring knowledge” to the more extreme position that reason is “the unique path to knowledge”.[7] Given a pre-modern understanding of reason, rationalism is identical to philosophy, the Socratic life of inquiry, or the zetetic (skeptical) clear interpretation of authority (open to the underlying or essential cause of things as they appear to our sense of certainty). In recent decades, Leo Strauss sought to revive “Classical Political Rationalism” as a discipline that understands the task of reasoning, not as foundational, but as maieutic.

In politics, rationalism, since the Enlightenment, historically emphasized a “politics of reason” centered upon rational choice, utilitarianism, secularism, and irreligion[8] the latter aspect’s antitheism later softened by politic adoption of pluralistic rationalist methods practicable regardless of religious or irreligious ideology.[9]

In this regard, the philosopher John Cottingham[10] noted how rationalism, a methodology, became socially conflated with atheism, a worldview:

In the past, particularly in the 17th and 18th centuries, the term ‘rationalist’ was often used to refer to free thinkers of an anti-clerical and anti-religious outlook, and for a time the word acquired a distinctly pejorative force (thus in 1670 Sanderson spoke disparagingly of ‘a mere rationalist, that is to say in plain English an atheist of the late edition…’). The use of the label ‘rationalist’ to characterize a world outlook which has no place for the supernatural is becoming less popular today; terms like ‘humanist’ or ‘materialist’ seem largely to have taken its place. But the old usage still survives.

Rationalism is often contrasted with empiricism. Taken very broadly these views are not mutually exclusive, since a philosopher can be both rationalist and empiricist.[4] Taken to extremes, the empiricist view holds that all ideas come to us a posteriori, that is to say, through experience; either through the external senses or through such inner sensations as pain and gratification. The empiricist essentially believes that knowledge is based on or derived directly from experience. The rationalist believes we come to knowledge a priori through the use of logic and is thus independent of sensory experience. In other words, as Galen Strawson once wrote, “you can see that it is true just lying on your couch. You don’t have to get up off your couch and go outside and examine the way things are in the physical world. You don’t have to do any science.”[11] Between both philosophies, the issue at hand is the fundamental source of human knowledge and the proper techniques for verifying what we think we know. Whereas both philosophies are under the umbrella of epistemology, their argument lies in the understanding of the warrant, which is under the wider epistemic umbrella of the theory of justification.

The theory of justification is the part of epistemology that attempts to understand the justification of propositions and beliefs. Epistemologists are concerned with various epistemic features of belief, which include the ideas of justification, warrant, rationality, and probability. Of these four terms, the term that has been most widely used and discussed by the early 21st century is “warrant”. Loosely speaking, justification is the reason that someone (probably) holds a belief.

If “A” makes a claim, and “B” then casts doubt on it, “A”‘s next move would normally be to provide justification. The precise method one uses to provide justification is where the lines are drawn between rationalism and empiricism (among other philosophical views). Much of the debate in these fields are focused on analyzing the nature of knowledge and how it relates to connected notions such as truth, belief, and justification.

At its core, rationalism consists of three basic claims. For one to consider themselves a rationalist, they must adopt at least one of these three claims: The Intuition/Deduction Thesis, The Innate Knowledge Thesis, or The Innate Concept Thesis. In addition, rationalists can choose to adopt the claims of Indispensability of Reason and or the Superiority of Reason although one can be a rationalist without adopting either thesis.

Rationale: “Some propositions in a particular subject area, S, are knowable by us by intuition alone; still others are knowable by being deduced from intuited propositions.”[12]

Generally speaking, intuition is a priori knowledge or experiential belief characterized by its immediacy; a form of rational insight. We simply “see” something in such a way as to give us a warranted belief. Beyond that, the nature of intuition is hotly debated.

In the same way, generally speaking, deduction is the process of reasoning from one or more general premises to reach a logically certain conclusion. Using valid arguments, we can deduce from intuited premises.

For example, when we combine both concepts, we can intuit that the number three is prime and that it is greater than two. We then deduce from this knowledge that there is a prime number greater than two. Thus, it can be said that intuition and deduction combined to provide us with a priori knowledge we gained this knowledge independently of sense experience.

Empiricists such as David Hume have been willing to accept this thesis for describing the relationships among our own concepts.[12] In this sense, empiricists argue that we are allowed to intuit and deduce truths from knowledge that has been obtained a posteriori.

By injecting different subjects into the Intuition/Deduction thesis, we are able to generate different arguments. Most rationalists agree mathematics is knowable by applying the intuition and deduction. Some go further to include ethical truths into the category of things knowable by intuition and deduction. Furthermore, some rationalists also claim metaphysics is knowable in this thesis.

In addition to different subjects, rationalists sometimes vary the strength of their claims by adjusting their understanding of the warrant. Some rationalists understand warranted beliefs to be beyond even the slightest doubt; others are more conservative and understand the warrant to be belief beyond a reasonable doubt.

Rationalists also have different understanding and claims involving the connection between intuition and truth. Some rationalists claim that intuition is infallible and that anything we intuit to be true is as such. More contemporary rationalists accept that intuition is not always a source of certain knowledge thus allowing for the possibility of a deceiver who might cause the rationalist to intuit a false proposition in the same way a third party could cause the rationalist to have perceptions of nonexistent objects.

Naturally, the more subjects the rationalists claim to be knowable by the Intuition/Deduction thesis, the more certain they are of their warranted beliefs, and the more strictly they adhere to the infallibility of intuition, the more controversial their truths or claims and the more radical their rationalism.[12]

To argue in favor of this thesis, Gottfried Wilhelm Leibniz, a prominent German philosopher, says, “The senses, although they are necessary for all our actual knowledge, are not sufficient to give us the whole of it, since the senses never give anything but instances, that is to say particular or individual truths. Now all the instances which confirm a general truth, however numerous they may be, are not sufficient to establish the universal necessity of this same truth, for it does not follow that what happened before will happen in the same way again. From which it appears that necessary truths, such as we find in pure mathematics, and particularly in arithmetic and geometry, must have principles whose proof does not depend on instances, nor consequently on the testimony of the senses, although without the senses it would never have occurred to us to think of them”[13]

Rationale: “We have knowledge of some truths in a particular subject area, S, as part of our rational nature.”[14]

The Innate Knowledge thesis is similar to the Intuition/Deduction thesis in the regard that both theses claim knowledge is gained a priori. The two theses go their separate ways when describing how that knowledge is gained. As the name, and the rationale, suggests, the Innate Knowledge thesis claims knowledge is simply part of our rational nature. Experiences can trigger a process that allows this knowledge to come into our consciousness, but the experiences don’t provide us with the knowledge itself. The knowledge has been with us since the beginning and the experience simply brought into focus, in the same way a photographer can bring the background of a picture into focus by changing the aperture of the lens. The background was always there, just not in focus.

This thesis targets a problem with the nature of inquiry originally postulated by Plato in Meno. Here, Plato asks about inquiry; how do we gain knowledge of a theorem in geometry? We inquire into the matter. Yet, knowledge by inquiry seems impossible.[15] In other words, “If we already have the knowledge, there is no place for inquiry. If we lack the knowledge, we don’t know what we are seeking and cannot recognize it when we find it. Either way we cannot gain knowledge of the theorem by inquiry. Yet, we do know some theorems.”[14] The Innate Knowledge thesis offers a solution to this paradox. By claiming that knowledge is already with us, either consciously or unconsciously, a rationalist claims we don’t really “learn” things in the traditional usage of the word, but rather that we simply bring to light what we already know.

Rationale: “We have some of the concepts we employ in a particular subject area, S, as part of our rational nature.”[16]

Similar to the Innate Knowledge thesis, the Innate Concept thesis suggests that some concepts are simply part of our rational nature. These concepts are a priori in nature and sense experience is irrelevant to determining the nature of these concepts (though, sense experience can help bring the concepts to our conscious mind).

Some philosophers, such as John Locke (who is considered one of the most influential thinkers of the Enlightenment and an empiricist) argue that the Innate Knowledge thesis and the Innate Concept thesis are the same.[17] Other philosophers, such as Peter Carruthers, argue that the two theses are distinct from one another. As with the other theses covered under the umbrella of rationalism, the more types and greater number of concepts a philosopher claims to be innate, the more controversial and radical their position; “the more a concept seems removed from experience and the mental operations we can perform on experience the more plausibly it may be claimed to be innate. Since we do not experience perfect triangles but do experience pains, our concept of the former is a more promising candidate for being innate than our concept of the latter.[16]

In his book, Meditations on First Philosophy,[18] Ren Descartes postulates three classifications for our ideas when he says, “Among my ideas, some appear to be innate, some to be adventitious, and others to have been invented by me. My understanding of what a thing is, what truth is, and what thought is, seems to derive simply from my own nature. But my hearing a noise, as I do now, or seeing the sun, or feeling the fire, comes from things which are located outside me, or so I have hitherto judged. Lastly, sirens, hippogriffs and the like are my own invention.”[19]

Adventitious ideas are those concepts that we gain through sense experiences, ideas such as the sensation of heat, because they originate from outside sources; transmitting their own likeness rather than something else and something you simply cannot will away. Ideas invented by us, such as those found in mythology, legends, and fairy tales are created by us from other ideas we possess. Lastly, innate ideas, such as our ideas of perfection, are those ideas we have as a result of mental processes that are beyond what experience can directly or indirectly provide.

Gottfried Wilhelm Leibniz defends the idea of innate concepts by suggesting the mind plays a role in determining the nature of concepts, to explain this, he likens the mind to a block of marble in the New Essays on Human Understanding, “This is why I have taken as an illustration a block of veined marble, rather than a wholly uniform block or blank tablets, that is to say what is called tabula rasa in the language of the philosophers. For if the soul were like those blank tablets, truths would be in us in the same way as the figure of Hercules is in a block of marble, when the marble is completely indifferent whether it receives this or some other figure. But if there were veins in the stone which marked out the figure of Hercules rather than other figures, this stone would be more determined thereto, and Hercules would be as it were in some manner innate in it, although labour would be needed to uncover the veins, and to clear them by polishing, and by cutting away what prevents them from appearing. It is in this way that ideas and truths are innate in us, like natural inclinations and dispositions, natural habits or potentialities, and not like activities, although these potentialities are always accompanied by some activities which correspond to them, though they are often imperceptible.”[20]

The three aforementioned theses of Intuition/Deduction, Innate Knowledge, and Innate Concept are the cornerstones of rationalism. To be considered a rationalist, one must adopt at least one of those three claims. The following two theses are traditionally adopted by rationalists, but they aren’t essential to the rationalist’s position.

The Indispensability of Reason Thesis has the following rationale, “The knowledge we gain in subject area, S, by intuition and deduction, as well as the ideas and instances of knowledge in S that are innate to us, could not have been gained by us through sense experience.”[3] In short, this thesis claims that experience cannot provide what we gain from reason.

The Superiority of Reason Thesis has the following rationale, ‘”The knowledge we gain in subject area S by intuition and deduction or have innately is superior to any knowledge gained by sense experience”.[3] In other words, this thesis claims reason is superior to experience as a source for knowledge.

In addition to the following claims, rationalists often adopt similar stances on other aspects of philosophy. Most rationalists reject skepticism for the areas of knowledge they claim are knowable a priori. Naturally, when you claim some truths are innately known to us, one must reject skepticism in relation to those truths. Especially for rationalists who adopt the Intuition/Deduction thesis, the idea of epistemic foundationalism tends to crop up. This is the view that we know some truths without basing our belief in them on any others and that we then use this foundational knowledge to know more truths.[3]

Rationalism – as an appeal to human reason as a way of obtaining knowledge – has a philosophical history dating from antiquity. The analytical nature of much of philosophical enquiry, the awareness of apparently a priori domains of knowledge such as mathematics, combined with the emphasis of obtaining knowledge through the use of rational faculties (commonly rejecting, for example, direct revelation) have made rationalist themes very prevalent in the history of philosophy.

Since the Enlightenment, rationalism is usually associated with the introduction of mathematical methods into philosophy as seen in the works of Descartes, Leibniz, and Spinoza.[5] This is commonly called continental rationalism, because it was predominant in the continental schools of Europe, whereas in Britain empiricism dominated.

Even then, the distinction between rationalists and empiricists was drawn at a later period and would not have been recognized by the philosophers involved. Also, the distinction between the two philosophies is not as clear-cut as is sometimes suggested; for example, Descartes and Locke have similar views about the nature of human ideas.[6]

Proponents of some varieties of rationalism argue that, starting with foundational basic principles, like the axioms of geometry, one could deductively derive the rest of all possible knowledge. The philosophers who held this view most clearly were Baruch Spinoza and Gottfried Leibniz, whose attempts to grapple with the epistemological and metaphysical problems raised by Descartes led to a development of the fundamental approach of rationalism. Both Spinoza and Leibniz asserted that, in principle, all knowledge, including scientific knowledge, could be gained through the use of reason alone, though they both observed that this was not possible in practice for human beings except in specific areas such as mathematics. On the other hand, Leibniz admitted in his book Monadology that “we are all mere Empirics in three fourths of our actions.”[7]

Although rationalism in its modern form post-dates antiquity, philosophers from this time laid down the foundations of rationalism.[citation needed] In particular, the understanding that we may be aware of knowledge available only through the use of rational thought.[citation needed]

Pythagoras was one of the first Western philosophers to stress rationalist insight.[21] He is often revered as a great mathematician, mystic and scientist, but he is best known for the Pythagorean theorem, which bears his name, and for discovering the mathematical relationship between the length of strings on lute and the pitches of the notes. Pythagoras “believed these harmonies reflected the ultimate nature of reality. He summed up the implied metaphysical rationalism in the words “All is number”. It is probable that he had caught the rationalist’s vision, later seen by Galileo (15641642), of a world governed throughout by mathematically formulable laws”.[21] It has been said that he was the first man to call himself a philosopher, or lover of wisdom.[22]

Plato held rational insight to a very high standard, as is seen in his works such as Meno and The Republic. He taught on the Theory of Forms (or the Theory of Ideas)[23][24][25] which asserts that the highest and most fundamental kind of reality is not the material world of change known to us through sensation, but rather the abstract, non-material (but substantial) world of forms (or ideas).[26] For Plato, these forms were accessible only to reason and not to sense.[21] In fact, it is said that Plato admired reason, especially in geometry, so highly that he had the phrase “Let no one ignorant of geometry enter” inscribed over the door to his academy.[27]

Aristotle’s main contribution to rationalist thinking was the use of syllogistic logic and its use in argument. Aristotle defines syllogism as “a discourse in which certain (specific) things having been supposed, something different from the things supposed results of necessity because these things are so.”[28] Despite this very general definition, Aristotle limits himself to categorical syllogisms which consist of three categorical propositions in his work Prior Analytics.[29] These included categorical modal syllogisms.[30]

Though the three great Greek philosophers disagreed with one another on specific points, they all agreed that rational thought could bring to light knowledge that was self-evident information that humans otherwise couldn’t know without the use of reason. After Aristotle’s death, Western rationalistic thought was generally characterized by its application to theology, such as in the works of the Islamic philosopher Avicenna and Jewish philosopher and theologian Maimonides. One notable event in the Western timelime was the philosophy of St. Thomas Aquinas who attempted to merge Greek rationalism and Christian revelation in the thirteenth-century.[21]

Early modern rationalism has its roots in the 17th-century Dutch Republic,[31] with some notable intellectual representatives like Hugo Grotius,[32] Ren Descartes, and Baruch Spinoza.

Descartes was the first of the modern rationalists and has been dubbed the ‘Father of Modern Philosophy.’ Much subsequent Western philosophy is a response to his writings,[33][34][35] which are studied closely to this day.

Descartes thought that only knowledge of eternal truths including the truths of mathematics, and the epistemological and metaphysical foundations of the sciences could be attained by reason alone; other knowledge, the knowledge of physics, required experience of the world, aided by the scientific method. He also argued that although dreams appear as real as sense experience, these dreams cannot provide persons with knowledge. Also, since conscious sense experience can be the cause of illusions, then sense experience itself can be doubtable. As a result, Descartes deduced that a rational pursuit of truth should doubt every belief about sensory reality. He elaborated these beliefs in such works as Discourse on Method, Meditations on First Philosophy, and Principles of Philosophy. Descartes developed a method to attain truths according to which nothing that cannot be recognised by the intellect (or reason) can be classified as knowledge. These truths are gained “without any sensory experience,” according to Descartes. Truths that are attained by reason are broken down into elements that intuition can grasp, which, through a purely deductive process, will result in clear truths about reality.

Descartes therefore argued, as a result of his method, that reason alone determined knowledge, and that this could be done independently of the senses. For instance, his famous dictum, cogito ergo sum or “I think, therefore I am”, is a conclusion reached a priori i.e., prior to any kind of experience on the matter. The simple meaning is that doubting one’s existence, in and of itself, proves that an “I” exists to do the thinking. In other words, doubting one’s own doubting is absurd.[36] This was, for Descartes, an irrefutable principle upon which to ground all forms of other knowledge. Descartes posited a metaphysical dualism, distinguishing between the substances of the human body (“res extensa”) and the mind or soul (“res cogitans”). This crucial distinction would be left unresolved and lead to what is known as the mind-body problem, since the two substances in the Cartesian system are independent of each other and irreducible.

The philosophy of Baruch Spinoza is a systematic, logical, rational philosophy developed in seventeenth-century Europe.[37][38][39] Spinoza’s philosophy is a system of ideas constructed upon basic building blocks with an internal consistency with which he tried to answer life’s major questions and in which he proposed that “God exists only philosophically.”[39][40] He was heavily influenced by Descartes,[41] Euclid[40] and Thomas Hobbes,[41] as well as theologians in the Jewish philosophical tradition such as Maimonides.[41] But his work was in many respects a departure from the Judeo-Christian tradition. Many of Spinoza’s ideas continue to vex thinkers today and many of his principles, particularly regarding the emotions, have implications for modern approaches to psychology. To this day, many important thinkers have found Spinoza’s “geometrical method”[39] difficult to comprehend: Goethe admitted that he found this concept confusing[citation needed]. His magnum opus, Ethics, contains unresolved obscurities and has a forbidding mathematical structure modeled on Euclid’s geometry.[40] Spinoza’s philosophy attracted believers such as Albert Einstein[42] and much intellectual attention.[43][44][45][46][47]

Leibniz was the last of the great Rationalists who contributed heavily to other fields such as metaphysics, epistemology, logic, mathematics, physics, jurisprudence, and the philosophy of religion; he is also considered to be one of the last “universal geniuses”.[48] He did not develop his system, however, independently of these advances. Leibniz rejected Cartesian dualism and denied the existence of a material world. In Leibniz’s view there are infinitely many simple substances, which he called “monads” (possibly taking the term from the work of Anne Conway).

Leibniz developed his theory of monads in response to both Descartes and Spinoza, because the rejection of their visions forced him to arrive at his own solution. Monads are the fundamental unit of reality, according to Leibniz, constituting both inanimate and animate objects. These units of reality represent the universe, though they are not subject to the laws of causality or space (which he called “well-founded phenomena”). Leibniz, therefore, introduced his principle of pre-established harmony to account for apparent causality in the world.

Kant is one of the central figures of modern philosophy, and set the terms by which all subsequent thinkers have had to grapple. He argued that human perception structures natural laws, and that reason is the source of morality. His thought continues to hold a major influence in contemporary thought, especially in fields such as metaphysics, epistemology, ethics, political philosophy, and aesthetics.[49]

Kant named his brand of epistemology “Transcendental Idealism”, and he first laid out these views in his famous work The Critique of Pure Reason. In it he argued that there were fundamental problems with both rationalist and empiricist dogma. To the rationalists he argued, broadly, that pure reason is flawed when it goes beyond its limits and claims to know those things that are necessarily beyond the realm of all possible experience: the existence of God, free will, and the immortality of the human soul. Kant referred to these objects as “The Thing in Itself” and goes on to argue that their status as objects beyond all possible experience by definition means we cannot know them. To the empiricist he argued that while it is correct that experience is fundamentally necessary for human knowledge, reason is necessary for processing that experience into coherent thought. He therefore concludes that both reason and experience are necessary for human knowledge. In the same way, Kant also argued that it was wrong to regard thought as mere analysis. “In Kant’s views, a priori concepts do exist, but if they are to lead to the amplification of knowledge, they must be brought into relation with empirical data”.[50]

Rationalism has become a rarer label tout court of philosophers today; rather many different kinds of specialised rationalisms are identified. For example, Robert Brandom has appropriated the terms rationalist expressivism and rationalist pragmatism as labels for aspects of his programme in Articulating Reasons, and identified linguistic rationalism, the claim that the content of propositions “are essentially what can serve as both premises and conclusions of inferences”, as a key thesis of Wilfred Sellars.[51]

Rationalism was criticized by William James for being out of touch with reality. James also criticized rationalism for representing the universe as a closed system, which contrasts to his view that the universe is an open system.[52]

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Rationalism – definition of rationalism by The Free Dictionary

I, for instance, would not be in the least surprised if all of a sudden, a propos of nothing, in the midst of general prosperity a gentleman with an ignoble, or rather with a reactionary and ironical, countenance were to arise and, putting his arms akimbo, say to us all: “I say, gentleman, hadn’t we better kick over the whole show and scatter rationalism to the winds, simply to send these logarithms to the devil, and to enable us to live once more at our own sweet foolish willHis ‘History of Rationalism in Europe,’ for example, is a very fine monument of the most thorough research and most effective statement; but to a mature mind its interest is equally conspicuous.Simon’s rationalism, I still affirm that Becker was only partly present.Karl Popper and Literary Theory: Critical Rationalism as a Philosophy of LiteratureTogether they provide a compelling record of the author’s longstanding concerns, most important among these the precise meaning of Leibniz’s rationalism–in what sense he maybe called a rationalist, and how his rationalism informs all of his other philosophical commitments.The first reductio shows that, from supposing that Weak Modal Rationalism is true, it follows that conceivability both is and is not conclusive evidence for possibility.To the waves of democratic expansion, social unrest, political revolutions, economic debacle, geopolitical uncertainty, and war, important intellectual elites of the Victorian Age responded with a deep and sweeping new approach to law: a “Great Alliance” between historicism, (4) rationalism, (5) and popular will.First collected in Rationalism in Politics and Other Essays (1962), the most influential were written in the postwar decade when Britain was debating the terms of her return to normality.Bennett, Words, Space, and the Audience: The Theatrical Tension Between Empiricism and Rationalism (New York: Palgrave Macmillan, 2012), Pages 179.Callahan argues quite convincingly that Oakeshott’s analysis of the errors of modern rationalism is both acute and accurate and that the American constitutional tradition has been informed by a highly rationalistic rhetorical style from the beginning.His topics include the Qur’anic background of rationalism in early Islam, the encounter of Islamic rationalism with Greek culture, the autonomy of philosophy in Islam, the assimilation of Islamic philosophical thought and dissociation in the Latin Middle Ages, and the manifestation of Islamic thought in an intertwined world.As the editors acknowledge, steps have been taken of late to explore more contextual, more varied approaches to philosophy in the early modern period and in particular to that strand in early modern philosophy known as rationalism.

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Rationalism (philosophy) | Article about Rationalism …

a collective designation for the architectural schools of the first half of the 20th century that made use of the achievements of modern science and technology. In the broad sense, rationalism in architecture is sometimes equated with the concept of modern architecture, as represented by the work of L. H. Sullivan in the United States, H. P. Berlage in the Netherlands, A. Loos in Austria, the masters of the Deutscher Werkbund in Germany, and A. Perret in France.

The establishment of rationalism in the early 1920s was largely promoted by the theories propagated by the circle of architects associated with the journal LEsprit nouveau. The movements leaders were Le Corbusier in France and W. Gro-pius of the Bauhaus school of architecture in Germany.

Rationalism flourished essentially from the 1920s through the 1950s. In 1928 its supporters organized the International Congress for Modern Architecture, which met until 1959. Rationalist ideas concerning urban planning were set forth in 1933 in the Athens Charter. In the 1950s the general architectural principles of rationalism led to the creation of the international style, represented by the work of L. Mies van der Rohe and many others. The dogmatic architectural ideas and the social-reformist utopianism of the proponents of rationalism led to a crisis in the movement by the late 1950s.

The Russian architects of Asnova (Association of New Architects), including N. A. Ladovskii and K. S. Melnikov, proclaimed themselves to be rationalists. They emphasized psychological and physiological factors in the appreciation of architectural form and sought rational principles in the visual aspect of architecture.

REFERENCESKhazanova, V. E. Sovelskaia arkhitektura pervykh let Oktiabria: 19171925 gg. Moscow. 1970.Banham, R. Theory and Design in the First Machine Age. London [1960].Collins, P. Changing Ideals in Modern Architecture: 17501950. London [1965].

a philosophical school that considers reason to be the foundation of human understanding and behavior. Rationalism is the opposite of fideism, irrationalism, and sensationalism (empiricism). The term rationalism has been used to designate and characterize philosophical concepts since the 19th century, but historically the rationalist tradition originated in ancient Greek philosophy. For example, Parmenides, who distinguished between the knowledge of truth (obtained through reason) and the knowledge of opinion (obtained through sensory perception), considered reason to be the criterion of truth.

Rationalism took shape in modern times as an integral system of epistemological views, as a result of the development of mathematics and the natural sciences. In contrast to medieval Scholasticism and religious dogmatism, the classical rationalism of the 17th and 18th centuries (Descartes, Spinoza, Male-branche, and Leibniz) was based on the idea of natural orderan infinite chain of causality pervading the world. Thus, the principles of rationalism were accepted by both materialists (Spinoza) and idealists (Leibniz), although the character of rationalism differed in the two philosophical trends, depending on how the question of the origin of knowledge was resolved.

The rationalism of the 17th and 18th centuries, which asserted the decisive role of reason in both human cognition and human activity, was one of the philosophical sources of the ideology of the Enlightenment. The cult of reason was also characteristic of the 18th-century French materialists, who adopted a philosophical position of materialistic sensationalism and criticized the speculative constructs of rationalism.

Seeking to substantiate the absolute reliability of the principles of science and the tenets of mathematics and the natural sciences, rationalism attempted to explain how knowledge obtained through human cognitive activity could be objective, universal, and necessary. Unlike sensationalism, rationalism maintained that scientific knowledge, which possesses these logical properties, could be attained through reason, which served as the source of knowledge and as the criterion of truth. For example, the rationalist Leibniz modified the basic thesis of sensationalism, as stated by Locke (there is nothing in reason that was not previously present in sensations) by appending to it the phrase other than reason itself. In other words, reason is capable of grasping not only the particular and the accidental, to which sensory perception is limited, but also the universal and the essential.

The concept of reason as the single source of scientific knowledge led rationalists to an idealist conclusion regarding the existence of innate ideas (Descartes) or of predispositions and inclinations in thought that are independent of sensory impressions (Leibniz). The underestimation by rationalists of the role of sensory perception, mans link with the external world, led to the separation of thought from the object of cognition.

Kant, who attempted to reconcile the ideas of rationalism and sensationalism, proposed that all our knowledge begins with the senses, passes to the faculty of understanding, and ends with reason (I. Kant, Sock, vol. 3, Moscow, 1964, p. 340). According to Kant, reason cannot serve as the universal criterion of truth. In order to explain the properties of knowledge, Kant introduced the concept of the apriority (a priori knowledge) of both conceptual forms (as in classical rationalism) and forms of contemplationspace and time. However, Kantian rationalism retains its force only at the price of adopting an agnostic positionthat is, it deals only with the world of phenomena and excludes consideration of things-in-themselves, or objective reality.

In Hegels philosophy the absolute idea, or absolute reason, is the original principle and essence of the world, and the process of cognition is viewed as the self-cognition of reason, which comprehends its own content in the world. In Hegel, therefore, the development of the objective world is represented as a purely logical, rational process, and rationalism assumes the character of panlogism.

Bourgeois philosophy of the 19th and 20th centuries (positivism and neopositivism, for example) lost faith in the unlimited power of reason. The prevailing trend in 19th- and 20th- century bourgeois philosophy is a critique of classical rationalism, with its ideals of the power of reason and mans unlimited rational activity. This critique is based either on irrationalism or on a moderate, limited rationalism. For example, Freudianism, which asserts the dominant role of irrational, subconscious elements, criticizes rationalism from the standpoint of irrationalism, as do intuitionism and existentialism. The concepts of M. Weber and K. Mannheim are representative of the critique of rationalism from the standpoint of moderate, limited rationalism, which is associated less with the logical problems of cognition and more with a search for the sociocultural bases and limits of rationalism.

The narrrow, one-sided character of rationalism was overcome in Marxism. It was possible to resolve the contradiction between empiricism and rationalism on the basis of fundamentally new principles developed in the theory of cognition of dialectical materialism. The basic condition for resolving the contradiction between empiricism and rationalism was an analysis of the process of cognition, in integral association with practical activity for transforming reality. V. I. Lenin wrote: From living perception to abstract thought, and from this to practice such is the dialectical path of the cognition of truth and the cognition of objective reality (Poln. sobr. soch., 5th ed., vol. 29, pp. 15253).

REFERENCESMarx, K. Tezisy o Feierbakhe. In K. Marx and F. Engels, Soch., 2nd ed., vol. 3.Engels, F. Dialektika prirody. Ibid., vol. 20.Lenin, V. I. Filosofskie tetradi. Poln. sobr. soch., 5th ed. vol. 29.Descartes, R. Rassuzhdenie o metode: Izbr. filosofskie proizvedeniia. Moscow, 1950.Leibniz, G. Novye opyty o chelovecheskom razume. Moscow, 1936.Istoriia filosofii, vol. 1. Moscow, 1957. Chapter 5.Girgensohn, K. Der Rationalismus des Abendlandes. Greifswald, 1921.Cassirer, E. Die Philosophie der Aufklrung. Tbingen, 1932.Santillana, G. de, and E. Zilsel. The Development of Rationalism and Empiricism. Chicago, 1941.

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Rationalism: Examples and Definition | Philosophy Terms

I. Definition

Rationalism is the philosophy that knowledge comes from logic and a certain kind of intuitionwhen we immediately know something to be true without deduction, such as I am conscious. Rationalists hold that the best way to arrive at certain knowledge is using the minds rational abilities. The opposite of rationalism is empiricism, or the view that knowledge comes from observing the outside world. However, in practice almost all philosophers and scientists use a combination of empiricism and rationalism.

Rationalism is an idea about where knowledge comes from, and is therefore part of the philosophical sub-field of epistemology.

Math provides a good illustration of rationalism: to a rationalist, you dont have to observe the world or have experiences in order to know that 1+1=2. You just have to understand the concepts one and addition, and then you can know that its true. Empiricists, on the other hand, argue that this is not true; they point out that we can only rely on mathematical equations based on some experience of the world, for example having one cookie, being given another, and then having two.

Rationalism and empiricism both play a role in science, though they correspond to different branches of science. Rationalism corresponds to mathematical analysis, whereas empiricism corresponds to experiments and observation.

Of course, the best route to knowledge combines rational contemplation and empirical observation. Rationalists and empiricists agree on that; they just disagree on which one is more important or primary.

Constructivism is an effort to combine empiricism and rationalism. According to constructivists, we can observe the world around us and gain a lot of knowledge this way (thats the empiricist part), but in order to understand or explain what we know, we have to fit it into an existing structure. That is, we have to construct a rational set of ideas that can make sense of the empirical data (thats the rationalist part). Constructivism is a popular idea among teachers, who find it helpful in structuring lessons: constructivist teaching involves presenting new information in a way designed to fit in with what the student already knows, so that they can gradually build up an understanding of the world for themselves.

Many people think that the progress of the human race is based on experiences of an empirical, critical nature, but I say that true knowledge is to be had only through a philosophy of deduction . . . Intuition makes us look at unrelated facts and then think about them until they can all be brought under one law. (Albert Einstein)

Many people think of science as an inherently empirical discipline after all, its based mainly on observation and experiments, right? But theres also a rationalist side to science as seen in this quote from Einstein. Einstein was not big on experiments or peering through telescopes. Instead, he took data that other people had collected and tried to understand it rationally (i.e. mathematically). His brilliant theories of special and general relativity were not the results of new experiments, but rather the result of applying a keen rational eyeand intuitionto existing data.

Music has always been inseparable from religious expression, since, like religion at its best, music marks the limits of reason. Because a territory is defined by its extremities, it follows that music must be definitively rational. (Karen Armstrong)

Many rationalist philosophers are fascinated by music, for exactly the reasons that Karen Armstrong points out in this quote. Music is intensely rational in some ways (you can analyze its structures and frequencies and find all sorts of mathematical patterns there), but its also extremely emotional and seems to short-circuit our rational brains. Thus, music exists right on the boundary between rational and anti-rational. Armstrong also makes the more controversial, but no less interesting, claim that religion works in a similar way, operating at the boundaries between rational thought and non-rational emotions.

Rationalism has deep historical roots; you might even say that its discovery defines the birth of philosophy in various cultures. The ancient Greeks are probably the most famous example: ancient philosophers such as Plato and Pythagoras argued that reality is characterized by some basic abstract logical principles, and that if we know these principles, then we can derive further truths about reality. (Thats the same Pythagoras who invented the famous Pythagorean Theorem more evidence of the connection between rationalism and math.)

However, other Greeks disagreed. Aristotle, for example, based much of his philosophy on observation. He was fascinated by the natural world and spent much of his time gathering samples of plants and animals; in some ways he was the first modern biologist. This method is, of course, based on observation and therefore is a kind of empiricism.

Rationalism really took off in the Medieval Islamic world, where Muslim philosophers looked to Plato for inspiration. Platos rationalism proved to be extremely important to medieval Islam, which was an intensely rationalistic religion based on logical deduction. Its first principle was tawheed, or the Unity of God, and all other truths were thought to be logical consequences of that single revelation.

Both rationalism and empiricism played a major role in the Scientific Revolution. Empiricists did experiments and made observations by, for example, looking through telescopes. But many of the most important discoveries were made by rational analysis, not empirical observation. And of course, the experiments were also partially inspired by reason and intuition.

Isaac Newton developed his theory of gravity by working out the mathematical relationship between falling objects and orbiting planets. (Sometimes people say that Newton discovered gravity, but really its more accurate to say that he explained gravity.)

The debate between rationalists and empiricists was resolved to some extent by Immanuel Kant, one of the most influential philosophers who ever lived. Kants theory was that empiricism and rationalism were both true in their own ways: he agreed with the empiricists when he said that all human knowledge comes from observation. This, he said, is in fact the way that people learn about the world. But our observations are also based on certain innate ways of reasoning; our brains are hard-wired to make certain conclusions from observation and reason further in certain ways. So, he also agreed with the rationalists that knowledge is determined by rationality. As you might expect, many constructivists can trace their lineage back to Kant.

In Civilization V, one of the social policy options is Rationalism. This social policy improves science output for your civilization and allows you to produce more Great Scientists. This makes sense since rationalism was so important in the early scientific revolution. However, the game illustrates rationalism with a picture of a scientist looking through a prism, presumably as part of an experiment. So the picture would fit better under the heading of empiricism rather than rationalism!

Vulcanians do not speculate. I speak from pure logic. (Spock, Star Trek)

Spock is the perfect rationalist. His powerful brain can compute logical probabilities faster than any human being, and he is not distracted by pesky emotions or personal biases (at least most of the time; he is half-human, after all). He is capable of incredible feats of logic, such as playing three-dimensional chess.

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Rationalism: Examples and Definition | Philosophy Terms

Rationalism | Britannica.com

Rationalism, in Western philosophy, the view that regards reason as the chief source and test of knowledge. Holding that reality itself has an inherently logical structure, the rationalist asserts that a class of truths exists that the intellect can grasp directly. There are, according to the rationalists, certain rational principlesespecially in logic and mathematics, and even in ethics and metaphysicsthat are so fundamental that to deny them is to fall into contradiction. The rationalists confidence in reason and proof tends, therefore, to detract from their respect for other ways of knowing.

Rationalism has long been the rival of empiricism, the doctrine that all knowledge comes from, and must be tested by, sense experience. As against this doctrine, rationalism holds reason to be a faculty that can lay hold of truths beyond the reach of sense perception, both in certainty and generality. In stressing the existence of a natural light, rationalism has also been the rival of systems claiming esoteric knowledge, whether from mystical experience, revelation, or intuition, and has been opposed to various irrationalisms that tend to stress the biological, the emotional or volitional, the unconscious, or the existential at the expense of the rational.

Rationalism has somewhat different meanings in different fields, depending upon the kind of theory to which it is opposed.

In the psychology of perception, for example, rationalism is in a sense opposed to the genetic psychology of the Swiss scholar Jean Piaget (18961980), who, exploring the development of thought and behaviour in the infant, argued that the categories of the mind develop only through the infants experience in concourse with the world. Similarly, rationalism is opposed to transactionalism, a point of view in psychology according to which human perceptual skills are achievements, accomplished through actions performed in response to an active environment. On this view, the experimental claim is made that perception is conditioned by probability judgments formed on the basis of earlier actions performed in similar situations. As a corrective to these sweeping claims, the rationalist defends a nativism, which holds that certain perceptual and conceptual capacities are innateas suggested in the case of depth perception by experiments with the visual cliff, which, though platformed over with firm glass, the infant perceives as hazardousthough these native capacities may at times lie dormant until the appropriate conditions for their emergence arise.

In the comparative study of languages, a similar nativism was developed in the 1950s by the innovating syntactician Noam Chomsky, who, acknowledging a debt to Ren Descartes (15961650), explicitly accepted the rationalistic doctrine of innate ideas. Though the thousands of languages spoken in the world differ greatly in sounds and symbols, they sufficiently resemble each other in syntax to suggest that there is a schema of universal grammar determined by innate presettings in the human mind itself. These presettings, which have their basis in the brain, set the pattern for all experience, fix the rules for the formation of meaningful sentences, and explain why languages are readily translatable into one another. It should be added that what rationalists have held about innate ideas is not that some ideas are full-fledged at birth but only that the grasp of certain connections and self-evident principles, when it comes, is due to inborn powers of insight rather than to learning by experience.

Common to all forms of speculative rationalism is the belief that the world is a rationally ordered whole, the parts of which are linked by logical necessity and the structure of which is therefore intelligible. Thus, in metaphysics it is opposed to the view that reality is a disjointed aggregate of incoherent bits and is thus opaque to reason. In particular, it is opposed to the logical atomisms of such thinkers as David Hume (171176) and the early Ludwig Wittgenstein (18891951), who held that facts are so disconnected that any fact might well have been different from what it is without entailing a change in any other fact. Rationalists have differed, however, with regard to the closeness and completeness with which the facts are bound together. At the lowest level, they have all believed that the law of contradiction A and not-A cannot coexist holds for the real world, which means that every truth is consistent with every other; at the highest level, they have held that all facts go beyond consistency to a positive coherence; i.e., they are so bound up with each other that none could be different without all being different.

In the field where its claims are clearestin epistemology, or theory of knowledgerationalism holds that at least some human knowledge is gained through a priori (prior to experience), or rational, insight as distinct from sense experience, which too often provides a confused and merely tentative approach. In the debate between empiricism and rationalism, empiricists hold the simpler and more sweeping position, the Humean claim that all knowledge of fact stems from perception. Rationalists, on the contrary, urge that some, though not all, knowledge arises through direct apprehension by the intellect. What the intellectual faculty apprehends is objects that transcend sense experienceuniversals and their relations. A universal is an abstraction, a characteristic that may reappear in various instances: the number three, for example, or the triangularity that all triangles have in common. Though these cannot be seen, heard, or felt, rationalists point out that humans can plainly think about them and about their relations. This kind of knowledge, which includes the whole of logic and mathematics as well as fragmentary insights in many other fields, is, in the rationalist view, the most important and certain knowledge that the mind can achieve. Such a priori knowledge is both necessary (i.e., it cannot be conceived as otherwise) and universal, in the sense that it admits of no exceptions. In the critical philosophy of Immanuel Kant (17241804), epistemological rationalism finds expression in the claim that the mind imposes its own inherent categories or forms upon incipient experience (see below Epistemological rationalism in modern philosophies).

In ethics, rationalism holds the position that reason, rather than feeling, custom, or authority, is the ultimate court of appeal in judging good and bad, right and wrong. Among major thinkers, the most notable representative of rational ethics is Kant, who held that the way to judge an act is to check its self-consistency as apprehended by the intellect: to note, first, what it is essentially, or in principlea lie, for example, or a theftand then to ask if one can consistently will that the principle be made universal. Is theft, then, right? The answer must be No, because, if theft were generally approved, peoples property would not be their own as opposed to anyone elses, and theft would then become meaningless; the notion, if universalized, would thus destroy itself, as reason by itself is sufficient to show.

In religion, rationalism commonly means that all human knowledge comes through the use of natural faculties, without the aid of supernatural revelation. Reason is here used in a broader sense, referring to human cognitive powers generally, as opposed to supernatural grace or faiththough it is also in sharp contrast to so-called existential approaches to truth. Reason, for the rationalist, thus stands opposed to many of the religions of the world, including Christianity, which have held that the divine has revealed itself through inspired persons or writings and which have required, at times, that its claims be accepted as infallible, even when they do not accord with natural knowledge. Religious rationalists hold, on the other hand, that if the clear insights of human reason must be set aside in favour of alleged revelation, then human thought is everywhere rendered suspecteven in the reasonings of the theologians themselves. There cannot be two ultimately different ways of warranting truth, they assert; hence rationalism urges that reason, with its standard of consistency, must be the final court of appeal. Religious rationalism can reflect either a traditional piety, when endeavouring to display the alleged sweet reasonableness of religion, or an antiauthoritarian temper, when aiming to supplant religion with the goddess of reason.

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Rationalism | Britannica.com

Rationalism (architecture) – Wikipedia

In architecture, rationalism is an architectural current which mostly developed from Italy in the 1920s-1930s. Vitruvius had claimed in his work De Architectura that architecture is a science that can be comprehended rationally. This formulation was taken up and further developed in the architectural treatises of the Renaissance. Progressive art theory of the 18th-century opposed the Baroque use of illusionism with the classic beauty of truth and reason.

Twentieth-century rationalism derived less from a special, unified theoretical work than from a common belief that the most varied problems posed by the real world could be resolved by reason. In that respect it represented a reaction to historicism and a contrast to Art Nouveau and Expressionism.

The name rationalism is retroactively applied to a movement in architecture that came about during the Enlightenment (more specifically, neoclassicism), arguing that architecture’s intellectual base is primarily in science as opposed to reverence for and emulation of archaic traditions and beliefs. Rational architects, following the philosophy of Ren Descartes emphasized geometric forms and ideal proportions.[1]:8184

The French Louis XVI style (better known as Neoclassicism) emerged in the mid-18th century with its roots in the waning interest of the Baroque period. The architectural notions of the time gravitated more and more to the belief that reason and natural forms are tied closely together, and that the rationality of science should serve as the basis for where structural members should be placed. Towards the end of the 18th century, Jean-Nicolas-Louis Durand, a teacher at the influential cole Polytechnique in Paris at the time, argued that architecture in its entirety was based in science.

Other architectural theorists of the period who advanced rationalist ideas include Abb Jean-Louis de Cordemoy (16311713),[2]:559[3]:265 the Venetian Carlo Lodoli (16901761),[2]:560 Abb Marc-Antoine Laugier (17131769) and Quatremre de Quincy (17551849).[1]:8792

The architecture of Claude Nicholas Ledoux (17361806) and tienne-Louis Boulle (172899) typify Enlightenment rationalism, with their use of pure geometric forms, including spheres, squares, and cylinders.[1]:9296

The term structural rationalism most often refers to a 19th-century French movement, usually associated with the theorists Eugne Viollet-le-Duc and Auguste Choisy. Viollet-le-Duc rejected the concept of an ideal architecture and instead saw architecture as a rational construction approach defined by the materials and purpose of the structure. The architect Eugne Train was one of the most important practitioners of this school, particularly with his educational buildings such as the Collge Chaptal and Lyce Voltaire.[4]

Architects such as Henri Labrouste and Auguste Perret incorporated the virtues of structural rationalism throughout the 19th century in their buildings. By the early 20th century, architects such as Hendrik Petrus Berlage were exploring the idea that structure itself could create space without the need for decoration. This gave rise to modernism, which further explored this concept. More specifically, the Soviet Modernist group ASNOVA were known as ‘the Rationalists’.

Rational Architecture (Italian: Architettura razionale) thrived in Italy from the 1920s to the 1940s. In 1926, a group of young architects Sebastiano Larco, Guido Frette, Carlo Enrico Rava, Adalberto Libera, Luigi Figini, Gino Pollini, and Giuseppe Terragni (190443) founded the so-called Gruppo 7, publishing their manifesto in the magazine Rassegna Italiana. Their declared intent was to strike a middle ground between the classicism of the Novecento Italiano movement and the industrially inspired architecture of Futurism.[5]:203 Their “note” declared:

The hallmark of the earlier avant garde was a contrived impetus and a vain, destructive fury, mingling good and bad elements: the hallmark of today’s youth is a desire for lucidity and wisdom…This must be clear…we do not intend to break with tradition…The new architecture, the true architecture, should be the result of a close association between logic and rationality.[5]:203

One of the first rationalist buildings was the Palazzo Gualino in Turin, built for the financier Riccardo Gualino by the architects Gino Levi-Montalcini and Giuseppe Pagano.[6] Gruppo 7 mounted three exhibitions between 1926 and 1931, and the movement constituted itself as an official body, the Movimento Italiano per l’Architettura Razionale (MIAR), in 1930. Exemplary works include Giuseppe Terragni’s Casa del Fascio in Como (193236), The Medaglia d’Oro room at the Italian Aeronautical Show in Milan (1934) by Pagano and Marcello Nizzoli, and the Fascist Trades Union Building in Como (193843), designed by Cesare Cattaneo, Pietro Lingeri, Augusto Magnani, L. Origoni, and Mario Terragni.[5]:2059

Pagano became editor of Casabella in 1933 together with Edoardo Persico. Pagano and Persico featured the work of the rationalists in the magazine, and its editorials urged the Italian state to adopt rationalism as its official style. The Rationalists enjoyed some official commissions from the Fascist government of Benito Mussolini, but the state tended to favor the more classically inspired work of the National Union of Architects. Architects associated with the movement collaborated on large official projects of the Mussolini regime, including the University of Rome (begun in 1932) and the Esposizione Universale Roma (EUR) in the southern part of Rome (begun in 1936). The EUR features monumental buildings, many of which evocative of ancient Roman architecture, but absent ornament, revealing strong geometric forms.[5]:2047

In the late 1960s, a new rationalist movement emerged in architecture, claiming inspiration from both the Enlightenment and early-20th-century rationalists. Like the earlier rationalists, the movement, known as the Tendenza, was centered in Italy. Practitioners include Carlo Aymonino (19262010), Aldo Rossi (193197), and Giorgio Grassi. The Italian design magazine Casabella featured the work of these architects and theorists. The work of architectural historian Manfredo Tafuri influenced the movement, and the University Iuav of Venice emerged as a center of the Tendenza after Tafuri became chair of Architecture History in 1968.[1]:157 et seq. A Tendenza exhibition was organized for the 1973 Milan Triennale.[1]:178183

Rossi’s book L’architettura della citt, published in 1966, and translated into English as The Architecture of the City in 1982, explored several of the ideas that inform Neo-rationalism. In seeking to develop an understanding of the city beyond simple functionalism, Rossi revives the idea of typology, following from Quatremre de Quincy, as a method for understanding buildings, as well as the larger city. He also writes of the importance of monuments as expressions of the collective memory of the city, and the idea of place as an expression of both physical reality and history.[1]:16672[7]:17880

Architects such as Leon Krier, Maurice Culot, and Demetri Porphyrios took Rossi’s ideas to their logical conclusion with a revival of Classical Architecture and Traditional Urbanism. Krier’s witty critique of Modernism, often in the form of cartoons, and Porphyrios’s well crafted philosophical arguments, such as “Classicism is not a Style”, won over a small but talented group of architects to the classical point of view. Organizations such as the Traditional Architecture Group at the RIBA, and the Institute of Classical Architecture attest to their growing number, but mask the Rationalist origins.

In Germany, Oswald Mathias Ungers became the leading practitioner of German rationalism from the mid-1960s.[7]:17880 Ungers influenced a younger generation of German architects, including Hans Kollhoff, Max Dudler, and Christoph Mckler.[8]

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Rationalism (architecture) – Wikipedia

Rationalism (architecture) – Wikipedia

In architecture, rationalism is an architectural current which mostly developed from Italy in the 1920s-1930s. Vitruvius had claimed in his work De Architectura that architecture is a science that can be comprehended rationally. This formulation was taken up and further developed in the architectural treatises of the Renaissance. Progressive art theory of the 18th-century opposed the Baroque use of illusionism with the classic beauty of truth and reason.

Twentieth-century rationalism derived less from a special, unified theoretical work than from a common belief that the most varied problems posed by the real world could be resolved by reason. In that respect it represented a reaction to historicism and a contrast to Art Nouveau and Expressionism.

The name rationalism is retroactively applied to a movement in architecture that came about during the Enlightenment (more specifically, neoclassicism), arguing that architecture’s intellectual base is primarily in science as opposed to reverence for and emulation of archaic traditions and beliefs. Rational architects, following the philosophy of Ren Descartes emphasized geometric forms and ideal proportions.[1]:8184

The French Louis XVI style (better known as Neoclassicism) emerged in the mid-18th century with its roots in the waning interest of the Baroque period. The architectural notions of the time gravitated more and more to the belief that reason and natural forms are tied closely together, and that the rationality of science should serve as the basis for where structural members should be placed. Towards the end of the 18th century, Jean-Nicolas-Louis Durand, a teacher at the influential cole Polytechnique in Paris at the time, argued that architecture in its entirety was based in science.

Other architectural theorists of the period who advanced rationalist ideas include Abb Jean-Louis de Cordemoy (16311713),[2]:559[3]:265 the Venetian Carlo Lodoli (16901761),[2]:560 Abb Marc-Antoine Laugier (17131769) and Quatremre de Quincy (17551849).[1]:8792

The architecture of Claude Nicholas Ledoux (17361806) and tienne-Louis Boulle (172899) typify Enlightenment rationalism, with their use of pure geometric forms, including spheres, squares, and cylinders.[1]:9296

The term structural rationalism most often refers to a 19th-century French movement, usually associated with the theorists Eugne Viollet-le-Duc and Auguste Choisy. Viollet-le-Duc rejected the concept of an ideal architecture and instead saw architecture as a rational construction approach defined by the materials and purpose of the structure. The architect Eugne Train was one of the most important practitioners of this school, particularly with his educational buildings such as the Collge Chaptal and Lyce Voltaire.[4]

Architects such as Henri Labrouste and Auguste Perret incorporated the virtues of structural rationalism throughout the 19th century in their buildings. By the early 20th century, architects such as Hendrik Petrus Berlage were exploring the idea that structure itself could create space without the need for decoration. This gave rise to modernism, which further explored this concept. More specifically, the Soviet Modernist group ASNOVA were known as ‘the Rationalists’.

Rational Architecture (Italian: Architettura razionale) thrived in Italy from the 1920s to the 1940s. In 1926, a group of young architects Sebastiano Larco, Guido Frette, Carlo Enrico Rava, Adalberto Libera, Luigi Figini, Gino Pollini, and Giuseppe Terragni (190443) founded the so-called Gruppo 7, publishing their manifesto in the magazine Rassegna Italiana. Their declared intent was to strike a middle ground between the classicism of the Novecento Italiano movement and the industrially inspired architecture of Futurism.[5]:203 Their “note” declared:

The hallmark of the earlier avant garde was a contrived impetus and a vain, destructive fury, mingling good and bad elements: the hallmark of today’s youth is a desire for lucidity and wisdom…This must be clear…we do not intend to break with tradition…The new architecture, the true architecture, should be the result of a close association between logic and rationality.[5]:203

One of the first rationalist buildings was the Palazzo Gualino in Turin, built for the financier Riccardo Gualino by the architects Gino Levi-Montalcini and Giuseppe Pagano.[6] Gruppo 7 mounted three exhibitions between 1926 and 1931, and the movement constituted itself as an official body, the Movimento Italiano per l’Architettura Razionale (MIAR), in 1930. Exemplary works include Giuseppe Terragni’s Casa del Fascio in Como (193236), The Medaglia d’Oro room at the Italian Aeronautical Show in Milan (1934) by Pagano and Marcello Nizzoli, and the Fascist Trades Union Building in Como (193843), designed by Cesare Cattaneo, Pietro Lingeri, Augusto Magnani, L. Origoni, and Mario Terragni.[5]:2059

Pagano became editor of Casabella in 1933 together with Edoardo Persico. Pagano and Persico featured the work of the rationalists in the magazine, and its editorials urged the Italian state to adopt rationalism as its official style. The Rationalists enjoyed some official commissions from the Fascist government of Benito Mussolini, but the state tended to favor the more classically inspired work of the National Union of Architects. Architects associated with the movement collaborated on large official projects of the Mussolini regime, including the University of Rome (begun in 1932) and the Esposizione Universale Roma (EUR) in the southern part of Rome (begun in 1936). The EUR features monumental buildings, many of which evocative of ancient Roman architecture, but absent ornament, revealing strong geometric forms.[5]:2047

In the late 1960s, a new rationalist movement emerged in architecture, claiming inspiration from both the Enlightenment and early-20th-century rationalists. Like the earlier rationalists, the movement, known as the Tendenza, was centered in Italy. Practitioners include Carlo Aymonino (19262010), Aldo Rossi (193197), and Giorgio Grassi. The Italian design magazine Casabella featured the work of these architects and theorists. The work of architectural historian Manfredo Tafuri influenced the movement, and the University Iuav of Venice emerged as a center of the Tendenza after Tafuri became chair of Architecture History in 1968.[1]:157 et seq. A Tendenza exhibition was organized for the 1973 Milan Triennale.[1]:178183

Rossi’s book L’architettura della citt, published in 1966, and translated into English as The Architecture of the City in 1982, explored several of the ideas that inform Neo-rationalism. In seeking to develop an understanding of the city beyond simple functionalism, Rossi revives the idea of typology, following from Quatremre de Quincy, as a method for understanding buildings, as well as the larger city. He also writes of the importance of monuments as expressions of the collective memory of the city, and the idea of place as an expression of both physical reality and history.[1]:16672[7]:17880

Architects such as Leon Krier, Maurice Culot, and Demetri Porphyrios took Rossi’s ideas to their logical conclusion with a revival of Classical Architecture and Traditional Urbanism. Krier’s witty critique of Modernism, often in the form of cartoons, and Porphyrios’s well crafted philosophical arguments, such as “Classicism is not a Style”, won over a small but talented group of architects to the classical point of view. Organizations such as the Traditional Architecture Group at the RIBA, and the Institute of Classical Architecture attest to their growing number, but mask the Rationalist origins.

In Germany, Oswald Mathias Ungers became the leading practitioner of German rationalism from the mid-1960s.[7]:17880 Ungers influenced a younger generation of German architects, including Hans Kollhoff, Max Dudler, and Christoph Mckler.[8]

See more here:

Rationalism (architecture) – Wikipedia

What is CR? – critical rationalism blogcritical …

I like to think of CR (critical rationalism) as a kind of evolving philosophical tradition concerning how we should approach knowledge. It is the Socratic method only with a little bit of modern awareness. While most philosophical traditions regard knowledge as something that has to be certain and justified, CR takes the view that we dont have ultimate answers, but knowledge is nevertheless possible. Truth is an endless quest.

The modern founder of critical rationalism was Karl Popper. Popper pointed out we can never justify anything, we merely criticize and weed out bad ideas and work with whats left. Poppers initial emphasis was on empirical science, where he solved the problem of induction, something that had been haunting philosophers and scientists for centuries. The problem of induction is this. No matter how many times weve seen an apple fall to the ground after weve dropped it, do we have any way to prove the same thing will happen next time we drop it. The answer is no. What Popper pointed out is that you can never justify any scientific theory, but you can falsify it. If I were to claim that all swans were white, one black swan would falsify my theory. In this way, science moves forward by weeding out bad theories, so to speak.

Popper said that science moves forward through a method of conjecture and refutation. While Popper was primarily interested in science, he often commented on political problems as well. Popper liked to emphasize the need for an open society, a society where people can speak out and criticize. After all, if science progresses through refutations, criticizing becomes essential. We need to speak out and therefore we need the freedom to do so. Popper was against any form of government that didnt give people the chance to speak out. Poppers thinking could probably best be summed up in this quote, I may be wrong and you may be right, and by an effort, we may get nearer to the truth.

Popper worked hard to expand his ideas, and so have several other people. CR should not be viewed as one mans philosophy, but as a growing philosophical tradition. One in which several people have contributed and are still contributing. One notable person was William Warren Bartley, III. Bartley worked towards expanding the idea of critical rationalism to cover all areas of knowledge, not just empirical science. Bartley felt that while in almost all areas of knowledge we seek justification, we should instead seek criticism. While nothing can ever be justified in any ultimate sense, certainly we can see error and weed it out. This is true whether we are dealing with empirical science and perhaps even knowledge of what is ethical. An important part of Bartleys thinking could probably best be summed up in this quote, How can our intellectual life and institutions, our tradition, and even our etiquette, sensibility, manners and customs, and behavior patterns, be arranged so as to expose our beliefs, conjectures, ideologies, policies, positions, programs, sources of ideas, traditions, and the like, to optimum criticism, so as at once to counteract and eliminate as much intellectual error as possible, and also so as to contribute to and insure the fertility of the intellectual econiche: to create an environment in which not only negative criticism but also positive creation of ideas, and the development of rationality, are truly inspired.

Neither Bartley or Popper have exhaustively explored the full potential of the CR philosophical tradition. Indeed, there are unlimited possibilities. While CR often emphasizes criticism, it also encourages new approaches and creative thinking. We need to come up with as many new ideas as we can, then let the process of criticism weed out the less workable ones. As CR accepts that the truth is out there and we are working towards it, it is actually a very optimistic philosophical tradition. Perhaps the most optimistic among the big three philosophical traditions. What are the big three traditions. Let me give you a quick summary.

One, dogmatism. Decide that you are privy to ultimate truth and then just follow that truth no matter what. Does such an attitude contribute to fanaticism? Perhaps.

Two, pessimism. Decide that truth is impossible, relative, random, meaningless. Just do whatever you want because nothing matters anyway. Does such an attitude contribute to random violence? Perhaps.

Three, critical rationalism, the truth is out there, but no one has a monopoly on it, so lets work together to try and get a little closer to it. Does such an attitude contribute to progress and mutual respect? More than likely.

If youd like more details than this then thats what this blog is for, please look around and explore.

Matt Dioguardi, blog administrator

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What is CR? – critical rationalism blogcritical …

critical rationalism blog – An exploration of critical …

CHAPTER 3 of my thesis Aspects of the Duhem Problem.

The previous chapter concluded with an account of the attempt by Lakatos to retrieve the salient features of falsificationism while accounting for the fact that a research programme may proceed in the face of numerous difficulties, just provided that there is occasional success. His methodology exploits the ambiguity of refutation (the Duhem-Quine problem) to permit a programme to proceed despite seemingly adverse evidence. According to a strict or naive interpretation of falsificationism, adverse evidence should cause the offending theory to be ditched forthwith but of course the point of the Duhem-Quine problem is that we do not know which among the major theory and auxiliary assumptions is at fault. The Lakatos scheme also exploits what is claimed to be an asymmetry in the impact of confirmations and refutations.

The Bayesians offer an explanation and a justification for Lakatos; at the same time they offer a possible solution to the Duhem-Quine problem. The Bayesian enterprise did not set out specifically to solve these problems because Bayesianism offers a comprehensive theory of scientific reasoning. However these are the kind of problems that such a comprehensive theory would be required to solve.

Howson and Ubrach, well-regarded and influential exponents of the Bayesian approach, provide an excellent all-round exposition and spirited polemics in defence of the Bayesian system in Scientific Reasoning: The Bayesian Approach (1989). In a nutshell, Bayesianism takes its point of departure from the fact that scientists tend to have degrees of belief in their theories and these degrees of belief obey the probability calculus. Or if their degrees of belief do not obey the calculus, then they should, in order to achieve rationality. According to Howson and Urbach probabilities should be understood as subjective assessments of credibility, regulated by the requirements that they be overall consistent (ibid 39).

They begin with some comments on the history of probability theory, starting with the Classical Theory, pioneered by Laplace. The classical theory aimed to provide a foundation for gamblers in their calculations of odds in betting, and also for philosophers and scientists to establish grounds of belief in the validity of inductive inference. The seminal book by Laplace was Philosophical Essays on Probabilities (1820) and the leading modern exponents of the Classical Theory have been Keynes and Carnap.

Objectivity is an important feature of the probabilities in the classical theory. They arise from a mathematical relationship between propositions and evidence, hence they are not supposed to depend on any subjective element of appraisal or perception. Carnaps quest for a principle of induction to establish the objective probability of scientific laws foundered on the fact that these laws had to be universal statements, applicable to an infinite domain. Thus no finite body of evidence could ever raise the probability of a law above zero (e divided by infinity is zero).

The Bayesian scheme does not depend on the estimation of objective probabilities in the first instance. The Bayesians start with the probabilities that are assigned to theories by scientists. There is a serious bone of contention among the Bayesians regarding the way that probabilities are assigned, whether they are a matter of subjective belief as argued by Howson and Urbach ( belief Bayesians) or a matter of behaviour, specifically betting behaviour (betting Bayesians).

The purpose of the Bayesian system is to explain the characteristic features of scientific inference in terms of the probabilites of the various rival hypotheses under consideration, relative to the available evidence, in particular the most recent evidence.

BAYESS THEOREM

Bayess Theorem can be written as follows:

P(h!e) = P(e!h)P(h) where P(h), and P(e) > 0P(e)

In this situation we are interested in the credibility of the hypothesis h relative to empirical evidence e. That is, the posterior probability, in the light of the evidence. Written in the above form the theorem states that the probability of the hypothesis conditional on the evidence (the posterior probability of the hypothesis) is equal to the probability of the evidence conditional on the hypothesis multiplied by the probability of the hypothesis in the absence of the evidence (the prior probability), all divided by the probability of the evidence.

Thus:

e confirms or supports h when P(h!e) > P(h)e disconfirms or undermines h when P(h!e)

The prior probability of h, designated as P(h) is that before e is considered. This will often be before e is available, but the system is still supposed to work when the evidence is in hand. In this case it has to be left out of account in evaluating the prior probability of the hypothesis. The posterior probability P(h!e) is that after e is admitted into consideration.

As Bayess Theorem shows, we can relate the posterior probability of a hypothesis to the terms P(h), P(e!h) and P(e). If we know the value of these three terms we can determine whether e confirms h, and more to the point, calculate P(h!e).

The capacity of the Bayesian scheme to provide a solution to the Duhem-Quine problem will be appraised in the light of two examples.

CASE 1. DORLING ON THE ACCELERATION OF THE MOON

Dorling (1979) provides an important case study, bearing directly on the Duhem-Quine problem in a paper titled Bayesian Personalism, the Methodology of Scientific Research Programmes, and Duhems Problem. He is concerned with two issues which arise from the work of Lakatos and one of these is intimately related to the Duhem-Quine problem.

1(a) Can a theory survive despite empirical refutation? How can the arrow of modus tollens be diverted from the theory to some auxiliary hypothesis? This is essentially the Duhem-Quine problem and it raises the closely related question;

1(b) Can we decide on some rational and empirical grounds whether the arrow of modus tollens should point at a (possibly) refuted theory or at (possibly) refuted auxiliaries?

2. How are we to account for the different weights that are assigned to confirmations and refutations?

In the history of physics and astronomy, successful precise quantitative predictions seem often to have been regarded as great triumphs when apparently similar unsuccessful predictions were regarded not as major disasters but as minor discrepancies. (Dorling, 1979, 177).

The case history concerns a clash between the observed acceleration of the moon and the calculated acceleration based on a hard core of Newtonian theory (T) and an essential auxiliary hypothesis (H) that the effects of tidal friction are too small to influence lunar acceleration. The aim is to evaluate T and H in the light of new and unexpected evidence (E) which was not consistent with them.

For the situation prior to the evidence E Dorling ascribed a probability of 0.9 to Newtonian theory (T) and 0.6 to the auxiliary hypothesis (H). He pointed out that the precise numbers do not matter all that much; we simply had one theory that was highly regarded, with subjective probability approaching 1 and another which was plausible but not nearly so strongly held.

The next step is to calculate the impact of the new evidence E on the subjective probabilities of T and H. This is done by calculating (by the Bayesian calculus) their posterior probabilities (after E) for comparison with the prior probabilities (0.9 and 0.6). One might expect that the unfavourable evidence would lower both by a similar amount, or at least a similar proportion.

Dorling explained that some other probabilities have to be assigned or calculated to feed into the Bayesian formula. Eventually we find that the probability of T has hardly shifted (down by 0.0024 to 0.8976) while in striking contrast the probability of H has collapsed by 0.597 to 0.003. According to Dorling this accords with scientific perceptions at the time and it supports the claim by Lakatos that a vigorous programme can survive refutations provided that it provides opportunities for further work and has some success. Newtonian theory would have easily survived this particular refutation because on the arithmetic its subjective probability scarcely changed.

This case is doubly valuable for the evaluation of Lakatos because by a historical accident it provided an example of a confirmation as well as a refutation. For a time it was believed that the evidence E supported Newton but subsequent work revealed that there had been an error in the calculations. The point is that before the error emerged, the apparent confirmation of T and H had been treated as a great triumph for the Newtonian programme. And of course we can run the Bayesian calculus, as though E had confirmed T and H, to find what the impact of the apparent confirmation would have been on their posterior probabilities. Their probabilities in this case increased to 0.996 and 0.964 respectively and Dorling uses this result to provide support for the claim that there is a powerfully asymmetrical effect on T between the refutation and the confirmation. He regards the decrease in P from 0.9 to 0.8976 as negligible while the increase to 0.996 represents a fall in the probability of error from 1/10 to 4/1000.

Thus the evidence has more impact in support than it has in opposition, a result from Bayes that agrees with Lakatos.

This latest result strongly suggests that a theory ought to be able to withstand a long succession of refutations of this sort, punctuated only by an occasional confirmation, and its subjective probability still steadily increase on average (Dorling, 1979, 186).

As to the relevance to Duhem-Quine problem; the task is to pick between H and T. In this instance the substantial reduction in P(H) would indicate that the H, the auxiliary hypothesis, is the weak link rather than the hard core of Newtonian theory.

CASE 2. HOWSON AND URBACH ON PROUTS LAW

The point of this example (used by Lakatos himself) is to show how a theory which appears to be refuted by evidence can survive as an active force for further development, being regarded more highly than the confounding evidence. When this happens, the Duhem-Quine problem is apparently again resolved in favour of the theory.

In 1815 William Prout suggested that hydrogen was a building block of other elements whose atomic weights were all multiples of the atomic weight of hydrogen. The fit was not exact, for example boron had a value of 0.829 when according to the theory it should have been 0.875 (a multiple of the figure 0.125). The measured figure for chlorine was 35.83 instead of 36. To overcome these discrepancies Prout and Thompson suggested that the values should be adjusted to fit the theory, with the deviations explained in terms of experimental error. In this case the arrow of modus tollens was directed from the theory to the experimental techniques.

In setting the scene for use of Bayesian theory, Howson and Urbach designated Prouts hypothesis as t. They refer to a as the hypothesis that the accuracy of measurements was adequate to produce an exact figure. The troublesome evidence is labelled e.

It seems that chemists of the early nineteenth century, such as Prout and Thompson, were fairly certain about the truth of t, but less so of a, though more sure that a is true than that it is false. (ibid, page 98)

In other words they were reasonably happy with their methods and the purity of their chemicals while accepting that they were not perfect.

Feeding in various estimates of the relevant prior probabilities, the effect was to shift from the prior probabilities to the posterior probabilities listed as follows:

P(t) = 0.9 shifted to P(t!e) = 0.878 (down 0.022)P(a) = 0.6 shifted to P(a!e) = 0.073 (down 0.527)

Howson and Urbach argued that these results explain why it was rational for Prout and Thomson to persist with Prouts hypothesis and to adjust atomic weight measurements to come into line with it. In other words, the arrow of modus tollens is validly directed to a and not t.

Howson and Urbach noted that the results are robust and are not seriously affected by altered initial probabilities: for example if P(t) is changed from 0.9 to 0.7 the posterior probabilities of t and a are 0.65 and 0.21 respectively, still ranking t well above a (though only by a factor of 3 rather than a factor of 10).

In the light of the calculation they noted Prouts hypothesis is still more likely to be true than false, and the auxiliary assumptions are still much more likely to be false than true (ibid 101). Their use of language was a little unfortunate because we now know that Prout was wrong and so Howson and Urbach would have done better to speak of credibility or likelihood instead of truth. Indeed, as will be explained, there were dissenting voices at the time.

REVIEW OF THE BAYESIAN APPROACH

Bayesian theory has many admirers, none more so than Howson and Urbach. In their view, the Bayesian approach should become dominant in the philosophy of science, and it should be taken on board by scientists as well. Confronted with evidence from research by Kahneman and Tversky that in his evaluation of evidence, man is apparently not a conservative Bayesian: he is not a Bayesian at all (Kahneman and Tversky, 1972, cited in Howson and Urbach, 1989, 293) they reply that:

it is not prejudicial to the conjecture that what we ourselves take to be correct inductive reasoning is Bayesian in character that there should be observable and sometimes systematic deviations from Bayesian preceptswe should be surprised if on every occasion subjects were apparently to employ impeccable Bayesian reasoning, even in the circumstances that they themselves were to regard Bayesian procedures as canonical. It is, after all, human to err. (Howson and Urbach, 1989, 293-285)

They draw some consolation from the lamentable performance of undergraduates (and a distressing fraction of logicians) in a simple deductive task (page 294). The task is to nominate which of four cards should be turned over to test the statement if a card has a vowel on one side, then it has an even number on the other side. The visible faces of the four cards are E, K, 4 and 7. The most common answers are the pair E and 4 or 4 alone. The correct answer is e and 7.

The Bayesian approach has some features that give offence to many people. Some object to the subjective elements, some to the arithmetic and some to the concept of probability which was so tarnished by the debacle of Carnaps programme.

Taking the last point first, Howson and Urbach argue cogently that the Bayesian approach should not be subjected to prejudice due to the failure of the classical theory of objective probabilities. The distinctively subjective starting point for the Bayesian calculus of course raises the objection of excessive subjectivism, with the possibility of irrational or arbitrary judgements. To this, Howson and Urbach reply that the structure of argument and calculation that follows after the assignment of prior probabilities resembles the objectivity of deductive inference (including mathematical calculation) from a set of premises. The source of the premises does not detract from the objectivity of the subsequent manipulations that may be performed upon them. Thus Bayesian subjectivism is not inherently more subjective than deductive reasoning.

EXCESSIVE REFLECTION OF THE INPUT

The input consists of prior probabilities (whether beliefs or betting propensities) and this raises another objection, along the lines that the Bayesians emerge with a conclusion (the posterior probability) which overwhelmingly reflects what was fed in, namely the prior probability. Against this is the argument that the prior probability (whatever it is) will shift rapidly towards a figure that reflects the impact of the evidence. Thus any arbitrariness or eccentricity of original beliefs will be rapidly corrected in a rational manner. The same mechanisms is supposed to result in rapid convergence between the belief values of different scientists.

To stand up, this latter argument must demonstrate that convergence cannot be equally rapidly achieved by non-Bayesian methods, such as offering a piece of evidence and discussing its implications for the various competing hypotheses or the alternative lines of work without recourse to Bayesian calculations.

As was noted previously, there is a considerable difference of opinion in Bayesian circles about the measure of subjective belief. Some want to use a behavioural measure (actual betting, or propensity to bet), others including Howson and Urbach opt for belief rather than behaviour. The betting Bayseians need to answer the question what, in scientific practice, is equivalent to betting? Is the notion of betting itself really relevant to the scientists situation? Betting forces a decision (or the bet does not get placed) but scientists can in principle refrain from a firm decision for ever (for good reasons or bad). This brings us back to the problems created by the demand to take a stand or make a decision one way or the other. Even if some kind of behavioural equivalent of betting is invoked, such as working on a particular programme or writing papers related to the programme, there is still the kind of problem, noted below, where a scientist works on a theory which he or she believes to be false.

Similarly formidable problems confront the belief Bayesians. Obviously any retrospective attribution of belief (as in the cases above) calls for heroic assumptions about the consciousness of people long dead. These assumptions expose the limitation with the forced choice approach which attempts to collapse all the criteria for the decision into a single value. Such an approach (for both betting and belief Bayesians) seems to preclude a complex appraisal of the theoretical problem situation which might be based on multiple criteria. Such an appraisal might run along the lines that theory A is better than theory B in solving some problems and C is better than B on some other criteria, and so certain types of work are required to test or develop each of the rival theories. This is the kind of situation envisaged by Lakatos when he developed his methodology of scientific research programmes.

The forced choice cannot comfortably handle the situation of Maxwell who continued to work on his theories even though he knew they had been found wanting in tests. Maxwell hoped that his theory would come good in the end, despite a persisting run of unfavourable results. Yet another situation is even harder to comprehend in Bayesian terms. Consider a scientist at work on an important and well established theory which that scientist believes (and indeed hopes) to be false. The scientist is working on the theory with the specific aim of refuting it, thus achieving the fame assigned to those who in some small way change the course of scientific history. The scientist is really betting on the falsehood of that theory. These comments reinforce the value of detaching the idea of working on a theory from the need to have belief in it, as noted in the chapter on the Popperians.

REVIEW OF THE CASES

What do the cases do for our appraisal of Bayesian subjectivism? The Dorling example is very impressive on both aspects of the Lakatos scheme swallowing an anomaly and thriving on a confirmation. The case for Bayesianism (and Lakatos) is reinforced by the fact that Dorling set out to criticise Lakatos, not to praise him. And he remained critical of any attempt to sidestep refutations because he did not accept that his findings provided any justification for ignoring refutations, along the lines of anything goes.

Finally, let me emphasise that this paper is intended to attack, not to defend, the position of Lakatos, Feyerabend and some of Kuhns disciples with respect to its cavalier attitude to refutations. I find this attitude rationally justified only under certain stringent conditions: p(T) must be substantially greater than 1/2, the anomalous result must not be readily explainable by any plausible rival theory to T(Dorling, 1979, 187).

In this passage Dorling possibly gives the game away. There must not be a significant rival theory that could account for the aberrant evidence E. In the absence of a potential rival to the main theory the battle between a previously successful and wide-ranging theory in one corner (in this case Newton) and a more or less isolated hypothesis and some awkward evidence in another corner is very uneven.

For this reason, it can be argued that the Bayesian scheme lets us down when we most need help that is, in a choice between major rival systems, a time of crisis with clashing paradigms, or a major challenge as when general relativity emerged as a serious alternative to Newtonian mechanics. Presumably the major theories (say Newton and Einstein) would have their prior probabilities lowered by the existence of the other, and the supposed aim of the Bayesian calculus in this situation should be to swing support one way or the other on the basis of the most recent evidence. The problem would be to determine which particular piece of evidence should be applied to make the calculations. Each theory is bound to have a great deal of evidence in support and if there is recourse to a new piece of evidence which appears to favour one rather than the other (the situation with the so-called crucial experiment) then the Duhem-Quine problem arises to challenge the interpretation of the evidence, whichever way it appears to go.

A rather different approach can be used in this situation. It derives from a method of analysis of decision making which was referred to by Popper as the logic of the situation but was replaced by talk of situational analysis to take the emphasis off logic. So far as the Duhem-Quine problem is concerned we can hardly appeal to the logic of the situation for a resolution because it is precisely the logic of the situation that is the problem. But we can appeal to an appraisal of the situation where choices have to be made from a limited range of options.

Scientists need to work in a framework of theory. Prior to the rise of Einstein, what theory could scientists use for some hundreds of years apart from that of Newton and his followers? In the absence of a rival of comparable scope or at least significant potential there was little alternative to further elaboration of the Newtonian scheme, even if anomalies persisted or accumulated. Awkward pieces of evidence create a challenge to a ruling theory but they do not by themselves provide an alternative. The same applies to the auxiliary hypothesis on tidal friction (mentioned the first case study above), unless this happens to derive from some non-Newtonian theoretical assumptions that can be extended to rival the Newtonian scheme.

The approach by situational analysis is not hostage to any theory of probability (objective or subjective), or likelihood, or certainty or inductive proof. Nor does it need to speculate about the truth of the ruling theory, in the way that Howson and Urbach speculate about the likelihood that a theory might be true.

This brings us to the Prout example which is not nearly as impressive as the Dorling case. Howson and Urbach concluded that the Duhem-Quine problem in that instance was resolved in favour of the theory against the evidence on the basis of a high subjective probability assigned to Prouts law by contemporary chemists. In the early stages of its career Prouts law may have achieved wide acceptance by the scientific community, at least in England, and for this reason Howson and Urbach assigned a very high subjective probability to Prouts hypothesis (0.9). However Continental chemists were always skeptical and by mid-century Staas (and quite likely his Continental colleagues) had concluded that the law was an illusion (Howson and Urbach, 1989, 98). This potentially damning testimony was not invoked by Howson and Urbach to reduce p(H), but it could have been (and probably should have been). Staas may well have given Prout the benefit of the doubt for some time over the experimental methodology, but as methods improved then the fit with Prout should have improved as well. Obviously the fit did not improve and under these circumstances Prout should have become less plausible, as indeed was the case outside England. If the view of Staas was widespread, then a much lower prior probability should have been used for Prouts theory.

Another point can be made about the high prior probability assigned to the hypothesis. The calculations show that the subjective probability of the evidence sank from 0.6 to 0.073 and this turned the case in favour of the theory. But there is a flaw of logic there: presumably the whole-number atomic numbers were calculated using the same experimental equipment and the same or similar techniques that were used to estimate the atomic number of Chlorine. And the high p for Prout was based on confidence in the experimental results that were used to pose the whole-number hypothesis in the first case. The evidence that was good enough to back the Prout conjecture should have been good enough to refute it, or at least dramatically lower its probability.

In the event, Prout turned out to be wrong, even if he was on the right track in seeking fundamental building blocks. The anomalies were due to isotopes which could not be separated or detected by chemical methods. So Prouts hypothesis may have provided a framework for ongoing work until the fundamental flaw was revealed by a major theoretical advance. As was the case with Newtonian mechanics in the light of the evidence on the acceleration of the moon, a simple-minded, pragmatic approach might have provided the same outcome without need of Bayesian calculations.

Consequently it is not true to claim, with Howson and Urbach that the Bayesian model is essentially correct. By contrast, non-probabilistic theories seem to lack entirely the resources that could deal with Duhems problem (Howson and Urbach, 1989, 101).

CONCLUDING COMMENTS

It appears that the Bayesian scheme has revealed a great deal of power in the Dorling example but is quite unimpressive in the Prout example. The requirement that there should not be a major rival theory on the scene is a great disadvantage because at other times there is little option but to keep working on the theory under challenge, even if some anomalies persist. Where the serious option exists it appears that the Bayesians do not help us to make a choice.

Furthermore, internal disagreements call for solutions before the Bayesians can hope to command wider assent; perhaps the most important of these is the difference between the betting and the belief schools of thought in the allocation of subjective probabilities. There is also the worrying aspect of betting behaviour which is adduced as a possible way of allocating priors but, as we have seen, there is no real equivalent of betting in scientific practice. One of the shortcomings of the Bayesian approach appears to be an excessive reliance on a particular piece of evidence (the latest) whereas the Popperians and especially Lakatos make allowance for time to turn up a great deal of evidence so that preferences may slowly emerge.

This brings us to the point of considering just how evidence does emerge, a topic which has not yet been mentioned but is an essential part of the situation. The next chapter will examine a mode of thought dubbed the New Experimentalism to take account of the dynamics of experimental programs.

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Rationalism: Examples and Definition | Philosophy Terms

I. Definition

Rationalism is the philosophy that knowledge comes from logic and a certain kind of intuitionwhen we immediately know something to be true without deduction, such as I am conscious. Rationalists hold that the best way to arrive at certain knowledge is using the minds rational abilities. The opposite of rationalism is empiricism, or the view that knowledge comes from observing the outside world. However, in practice almost all philosophers and scientists use a combination of empiricism and rationalism.

Rationalism is an idea about where knowledge comes from, and is therefore part of the philosophical sub-field of epistemology.

Math provides a good illustration of rationalism: to a rationalist, you dont have to observe the world or have experiences in order to know that 1+1=2. You just have to understand the concepts one and addition, and then you can know that its true. Empiricists, on the other hand, argue that this is not true; they point out that we can only rely on mathematical equations based on some experience of the world, for example having one cookie, being given another, and then having two.

Rationalism and empiricism both play a role in science, though they correspond to different branches of science. Rationalism corresponds to mathematical analysis, whereas empiricism corresponds to experiments and observation.

Of course, the best route to knowledge combines rational contemplation and empirical observation. Rationalists and empiricists agree on that; they just disagree on which one is more important or primary.

Constructivism is an effort to combine empiricism and rationalism. According to constructivists, we can observe the world around us and gain a lot of knowledge this way (thats the empiricist part), but in order to understand or explain what we know, we have to fit it into an existing structure. That is, we have to construct a rational set of ideas that can make sense of the empirical data (thats the rationalist part). Constructivism is a popular idea among teachers, who find it helpful in structuring lessons: constructivist teaching involves presenting new information in a way designed to fit in with what the student already knows, so that they can gradually build up an understanding of the world for themselves.

Many people think that the progress of the human race is based on experiences of an empirical, critical nature, but I say that true knowledge is to be had only through a philosophy of deduction . . . Intuition makes us look at unrelated facts and then think about them until they can all be brought under one law. (Albert Einstein)

Many people think of science as an inherently empirical discipline after all, its based mainly on observation and experiments, right? But theres also a rationalist side to science as seen in this quote from Einstein. Einstein was not big on experiments or peering through telescopes. Instead, he took data that other people had collected and tried to understand it rationally (i.e. mathematically). His brilliant theories of special and general relativity were not the results of new experiments, but rather the result of applying a keen rational eyeand intuitionto existing data.

Music has always been inseparable from religious expression, since, like religion at its best, music marks the limits of reason. Because a territory is defined by its extremities, it follows that music must be definitively rational. (Karen Armstrong)

Many rationalist philosophers are fascinated by music, for exactly the reasons that Karen Armstrong points out in this quote. Music is intensely rational in some ways (you can analyze its structures and frequencies and find all sorts of mathematical patterns there), but its also extremely emotional and seems to short-circuit our rational brains. Thus, music exists right on the boundary between rational and anti-rational. Armstrong also makes the more controversial, but no less interesting, claim that religion works in a similar way, operating at the boundaries between rational thought and non-rational emotions.

Rationalism has deep historical roots; you might even say that its discovery defines the birth of philosophy in various cultures. The ancient Greeks are probably the most famous example: ancient philosophers such as Plato and Pythagoras argued that reality is characterized by some basic abstract logical principles, and that if we know these principles, then we can derive further truths about reality. (Thats the same Pythagoras who invented the famous Pythagorean Theorem more evidence of the connection between rationalism and math.)

However, other Greeks disagreed. Aristotle, for example, based much of his philosophy on observation. He was fascinated by the natural world and spent much of his time gathering samples of plants and animals; in some ways he was the first modern biologist. This method is, of course, based on observation and therefore is a kind of empiricism.

Rationalism really took off in the Medieval Islamic world, where Muslim philosophers looked to Plato for inspiration. Platos rationalism proved to be extremely important to medieval Islam, which was an intensely rationalistic religion based on logical deduction. Its first principle was tawheed, or the Unity of God, and all other truths were thought to be logical consequences of that single revelation.

Both rationalism and empiricism played a major role in the Scientific Revolution. Empiricists did experiments and made observations by, for example, looking through telescopes. But many of the most important discoveries were made by rational analysis, not empirical observation. And of course, the experiments were also partially inspired by reason and intuition.

Isaac Newton developed his theory of gravity by working out the mathematical relationship between falling objects and orbiting planets. (Sometimes people say that Newton discovered gravity, but really its more accurate to say that he explained gravity.)

The debate between rationalists and empiricists was resolved to some extent by Immanuel Kant, one of the most influential philosophers who ever lived. Kants theory was that empiricism and rationalism were both true in their own ways: he agreed with the empiricists when he said that all human knowledge comes from observation. This, he said, is in fact the way that people learn about the world. But our observations are also based on certain innate ways of reasoning; our brains are hard-wired to make certain conclusions from observation and reason further in certain ways. So, he also agreed with the rationalists that knowledge is determined by rationality. As you might expect, many constructivists can trace their lineage back to Kant.

In Civilization V, one of the social policy options is Rationalism. This social policy improves science output for your civilization and allows you to produce more Great Scientists. This makes sense since rationalism was so important in the early scientific revolution. However, the game illustrates rationalism with a picture of a scientist looking through a prism, presumably as part of an experiment. So the picture would fit better under the heading of empiricism rather than rationalism!

Vulcanians do not speculate. I speak from pure logic. (Spock, Star Trek)

Spock is the perfect rationalist. His powerful brain can compute logical probabilities faster than any human being, and he is not distracted by pesky emotions or personal biases (at least most of the time; he is half-human, after all). He is capable of incredible feats of logic, such as playing three-dimensional chess.

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Rationalism: Examples and Definition | Philosophy Terms

Rationalism – New World Encyclopedia

Rationalism is a broad family of positions in epistemology. Perhaps the best general description of rationalism is the view that there are some distinctive aspects or faculties of the mind that (1) are distinct from passive aspects of the mind such as sense-perceptions and (2) someway or other constitute a special source (perhaps only a partial source) of knowledge. These distinctive aspects are typically associated or identified with human abilities to engage in mathematics and abstract reasoning, and the knowledge they provide is often seen as of a type that could not have come from other sources. Philosophers who resist rationalism are usually grouped under the heading of empiricists, who are often allied under the claim that all human knowledge comes from experience.

The debate around which the rationalism/empiricism distinction revolves is one of the oldest and most continuous in philosophy. Some of Plato’s most explicit arguments address the topic and it was arguably the central concern of many of the Modern thinkers. Indeed, Kant’s principal works were concerned with “pure” faculties of reason. Contemporary philosophers have advanced and refined the issue, though there are current thinkers who align themselves with either side of the tradition.

It is difficult to identify a major figure in the history to whom some rationalist doctrine has not been attributed at some point. One reason for this is that there is no question that humans possess some sort of reasoning ability that allows them to come to know some facts they otherwise wouldn’t (for instance, mathematical facts), and every philosopher has had to acknowledge this fact. Another reason is that the very business of philosophy is to achieve knowledge by using the rational faculties, in contrast to, for instance, mystical approaches to knowledge. Nevertheless, some philosophical figures stand out as attributing even greater significance to reasoning abilities. Three are discussed here: Plato, Descartes, and Kant.

The most famous metaphysical doctrine of the great Greek philosopher Plato is his doctrine of “Forms,” as espoused in The Republic and other dialogues. The Forms are described as being outside of the world as experience by the senses, but as somehow constituting the metaphysical basis of the world. Exactly how they fulfill this function is generally only gestured at through analogies, though the Timaeus describes the Forms as operating as blueprints for the craftsman of the universe.

The distinctiveness of Plato’s rationalism lies in another aspect of his theory of Forms. Though the common sense position is that the senses are one’s best means of getting in touch with reality, Plato held that human reasoning ability was the one thing that allowed people to approach the Forms, the most fundamental aspects of reality. It is worth pausing to reflect on how radical this idea is: On such a view, philosophical attempts to understand the nature of “good” or “just” are not mere analyses of concepts formed, but rather explorations of eternal things that are responsible for shaping the reality of the sensory world.

The French philosopher Ren Descartes, whose Meditations on First Philosophy defined the course of much philosophy from then up till the present day, stood near the beginning of the Western European Enlightenment. Impressed by the power of mathematics and the development of the new science, Descartes was confronted with two questions: How was it that people were coming to attain such deep knowledge of the workings of the universe, and how was it that they had spent so long not doing so?

Regarding the latter question, Descartes concluded that people had been mislead by putting too much faith in the testimony of their senses. In particular, he thought such a mistake was behind the then-dominant physics of Aristotle. Aristotle and the later Scholastics, in Descartes’ mind, had used their reasoning abilities well enough on the basis of what their senses told them. The problem was that they had chosen the wrong starting point for their inquiries.

By contrast, the advancements in the new science (some of which Descartes could claim for himself) were based in a very different starting point: The “pure light of reason.” In Descartes’ view, God had equipped humans with a faculty that was able to understand the fundamental essence of the two types of substance that made up the world: Intellectual substance (of which minds are instances) and physical substance (matter). Not only did God give people such a faculty, Descartes claimed, but he made them such that, when using the faculty, they are unable to question its deliverances. Not only that, but God left humanity the means to conclude that the faculty was a gift from a non-deceptive omnipotent creator.

In some respects, the German philosophy Immanuel Kant is the paradigm of an anti-rationalist philosopher. A major portion of his central work, the 1781 Critique of Pure Reason, is specifically devoted to attacking rationalist claims to have insight through reason alone into the nature of the soul, the spatiotemporal/causal structure of the universe, and the existence of God. Plato and Descartes are among his most obvious targets.

For instance, in his evaluation of rationalist claims concerning the nature of the soul (the chapter of the Critique entitled “The Paralogisms of Pure Reason”), Kant attempts to diagnose how a philosopher like Descartes could have been tempted into thinking that he could accomplish deep insight into his own nature by thought alone. One of Descartes’ conclusions was that his mind, unlike his body, was utterly simple and so lacked parts. Kant claimed that Descartes mistook a simple experience (the thought, “I think”) for an experience of simplicity. In other words, he saw Descartes as introspecting, being unable to find any divisions within himself, and thereby concluding that he lacked any such divisions and so was simple. But the reason he was unable to find divisions, in Kant’s view, was that by mere thought alone we are unable to find anything.

At the same time, however, Kant was an uncompromising advocate of some key rationalist intuitions. Confronted with the Scottish philosopher David Hume’s claim that the concept of “cause” was merely one of the constant conjunction of resembling entities, Kant insisted that all Hume really accomplished was in proving that the concept of causation could not possibly have its origin in human senses. What the senses cannot provide, Kant claimed, is any notion of necessity, yet a crucial part of our concept of causation is that it is the necessary connection of two entities or events. Kant’s conclusion was that this concept, and others like it, must be a precondition of sensory experience itself.

In his moral philosophy (most famously expounded in his Groundwork for the Metaphysics of Morals), Kant made an even more original claim on behalf of reason. The sensory world, in his view, was merely ideal, in that the spatiotemporal/sensory features of the objects people experience have their being only in humanity’s representations, and so are not features of the objects in themselves. But this means that most everyday concepts are simply inadequate for forming any notion whatsoever of what the world is like apart from our subjective features. By contrast, Kant claimed that there was no parallel reason for thinking that objects in themselves (which include our soul) do not conform to the most basic concepts of our higher faculties. So while those faculties are unable to provide any sort of direct, reliable access to the basic features of reality as envisioned by Plato and Descartes, they and they alone give one the means to at least contemplate what true reality might be like.

In the early part of the twentieth century, a philosophical movement known as Logical Positivism set the ground for a new debate over rationalism. The positivists (whose ranks included Otto Neurath and Rudolf Carnap) claimed that the only meaningful claims were those that could potentially be verified by some set of experiential observations. Their aim was to do away with intellectual traditions that they saw as simply vacuous, including theology and the majority of philosophy, in contrast with science.

As it turned out, the Positivists were unable to explain how all scientific claims were verifiable by experience, thus losing their key motivation (for instance, no set of experiences could verify that all stars are hot, since no set of experiential observations could itself confirm that one had observed all the stars). Nevertheless, their vision retained enough force that later philosophers felt hard-pressed to explain what, if anything, was epistemically distinctive about the non-sensory faculties. One recent defense of rationalism can be found in the work of contemporary philosophers such as Laurence Bonjour (the recent developments of the position are, in general, too subtle to be adequately addressed here). Yet the charge was also met by a number of thinkers working in areas as closely related to psychology as to philosophy.

A number of thinkers have argued for something like Kant’s view that people have concepts independently of experience. Indeed, the groundbreaking work of the linguist Noam Chomsky (which he occasionally tied to Descartes) is largely based on the assumption that there is a “universal grammar”that is, some basic set of linguistic categories and abilities that necessarily underlie all human languages. One task of linguistics, in Chomsky’s view, is to look at a diversity of languages in order to determine what the innate linguistic categories and capacities are.

A similar proposal concerning human beliefs about mentality itself has been advanced by Peter Carruthers. One intuitive view is that each of us comes to attribute mental states to other people only after a long developmental process where people learn to associate observable phenomena with their own mental states, and thereby with others. Yet, Carruthers argues, this view simply cannot account for the speed and complexity of humans’ understanding of others’ psychology at very early ages. The only explanation is that some understanding of mentality is “hard-wired” in the human brain.

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