Atheism as rejection of religious beliefs
A central, common core of Judaism, Christianity, and Islam is the affirmation of the reality of one, and only one, God. Adherents of these faiths believe that there is a God who created the universe out of nothing and who has absolute sovereignty over all his creation; this includes, of course, human beingswho are not only utterly dependent on this creative power but also sinful and who, or so the faithful must believe, can only make adequate sense of their lives by accepting, without question, Gods ordinances for them. The varieties of atheism are numerous, but all atheists reject such a set of beliefs.
Atheism, however, casts a wider net and rejects all belief in spiritual beings, and to the extent that belief in spiritual beings is definitive of what it means for a system to be religious, atheism rejects religion. So atheism is not only a rejection of the central conceptions of Judaism, Christianity, and Islam; it is, as well, a rejection of the religious beliefs of such African religions as that of the Dinka and the Nuer, of the anthropomorphic gods of classical Greece and Rome, and of the transcendental conceptions of Hinduism and Buddhism. Generally atheism is a denial of God or of the gods, and if religion is defined in terms of belief in spiritual beings, then atheism is the rejection of all religious belief.
It is necessary, however, if a tolerably adequate understanding of atheism is to be achieved, to give a reading to rejection of religious belief and to come to realize how the characterization of atheism as the denial of God or the gods is inadequate.
To say that atheism is the denial of God or the gods and that it is the opposite of theism, a system of belief that affirms the reality of God and seeks to demonstrate his existence, is inadequate in a number of ways. First, not all theologians who regard themselves as defenders of the Christian faith or of Judaism or Islam regard themselves as defenders of theism. The influential 20th-century Protestant theologian Paul Tillich, for example, regards the God of theism as an idol and refuses to construe God as a being, even a supreme being, among beings or as an infinite being above finite beings. God, for him, is being-itself, the ground of being and meaning. The particulars of Tillichs view are in certain ways idiosyncratic, as well as being obscure and problematic, but they have been influential; and his rejection of theism, while retaining a belief in God, is not eccentric in contemporary theology, though it may very well affront the plain believer.
Second, and more important, it is not the case that all theists seek to demonstrate or even in any way rationally to establish the existence of God. Many theists regard such a demonstration as impossible, and fideistic believers (e.g., Johann Hamann and Sren Kierkegaard) regard such a demonstration, even if it were possible, as undesirable, for in their view it would undermine faith. If it could be proved, or known for certain, that God exists, people would not be in a position to accept him as their sovereign Lord humbly on faith with all the risks that entails. There are theologians who have argued that for genuine faith to be possible God must necessarily be a hidden God, the mysterious ultimate reality, whose existence and authority must be accepted simply on faith. This fideistic view has not, of course, gone without challenge from inside the major faiths, but it is of sufficient importance to make the above characterization of atheism inadequate.
Finally, and most important, not all denials of God are denials of his existence. Believers sometimes deny God while not being at all in a state of doubt that God exists. They either willfully reject what they take to be his authority by not acting in accordance with what they take to be his will, or else they simply live their lives as if God did not exist. In this important way they deny him. Such deniers are not atheists (unless we wish, misleadingly, to call them practical atheists). They are not even agnostics. They do not question that God exists; they deny him in other ways. An atheist denies the existence of God. As it is frequently said, atheists believe that it is false that God exists, or that Gods existence is a speculative hypothesis of an extremely low order of probability.
Yet it remains the case that such a characterization of atheism is inadequate in other ways. For one it is too narrow. There are atheists who believe that the very concept of God, at least in developed and less anthropomorphic forms of Judeo-Christianity and Islam, is so incoherent that certain central religious claims, such as God is my creator to whom everything is owed, are not genuine truth-claims; i.e., the claims could not be either true or false. Believers hold that such religious propositions are true, some atheists believe that they are false, and there are agnostics who cannot make up their minds whether to believe that they are true or false. (Agnostics think that the propositions are one or the other but believe that it is not possible to determine which.) But all three are mistaken, some atheists argue, for such putative truth-claims are not sufficiently intelligible to be genuine truth-claims that are either true or false. In reality there is nothing in them to be believed or disbelieved, though there is for the believer the powerful and humanly comforting illusion that there is. Such an atheism, it should be added, rooted for some conceptions of God in considerations about intelligibility and what it makes sense to say, has been strongly resisted by some pragmatists and logical empiricists.
While the above considerations about atheism and intelligibility show the second characterization of atheism to be too narrow, it is also the case that this characterization is in a way too broad. For there are fideistic believers, who quite unequivocally believe that when looked at objectively the proposition that God exists has a very low probability weight. They believe in God not because it is probable that he existsthey think it more probable that he does notbut because belief is thought by them to be necessary to make sense of human life. The second characterization of atheism does not distinguish a fideistic believer (a Blaise Pascal or a Soren Kierkegaard) or an agnostic (a T.H. Huxley or a Sir Leslie Stephen) from an atheist such as Baron dHolbach. All believe that there is a God and God protects humankind, however emotionally important they may be, are speculative hypotheses of an extremely low order of probability. But this, since it does not distinguish believers from nonbelievers and does not distinguish agnostics from atheists, cannot be an adequate characterization of atheism.
It may be retorted that to avoid apriorism and dogmatic atheism the existence of God should be regarded as a hypothesis. There are no ontological (purely a priori) proofs or disproofs of Gods existence. It is not reasonable to rule in advance that it makes no sense to say that God exists. What the atheist can reasonably claim is that there is no evidence that there is a God, and against that background he may very well be justified in asserting that there is no God. It has been argued, however, that it is simply dogmatic for an atheist to assert that no possible evidence could ever give one grounds for believing in God. Instead, atheists should justify their unbelief by showing (if they can) how the assertion is well-taken that there is no evidence that would warrant a belief in God. If atheism is justified, the atheist will have shown that in fact there is no adequate evidence for the belief that God exists, but it should not be part of his task to try to show that there could not be any evidence for the existence of God. If the atheist could somehow survive the death of his present body (assuming that such talk makes sense) and come, much to his surprise, to stand in the presence of God, his answer should be, Oh! Lord, you didnt give me enough evidence! He would have been mistaken, and realize that he had been mistaken, in his judgment that God did not exist. Still, he would not have been unjustified, in the light of the evidence available to him during his earthly life, in believing as he did. Not having any such postmortem experiences of the presence of God (assuming that he could have them), what he should say, as things stand and in the face of the evidence he actually has and is likely to be able to get, is that it is false that God exists. (Every time one legitimately asserts that a proposition is false one need not be certain that it is false. Knowing with certainty is not a pleonasm.) The claim is that this tentative posture is the reasonable position for the atheist to take.
An atheist who argues in this manner may also make a distinctive burden-of-proof argument. Given that God (if there is one) is by definition a very recherch realitya reality that must be (for there to be such a reality) transcendent to the worldthe burden of proof is not on the atheist to give grounds for believing that there is no reality of that order. Rather, the burden of proof is on the believer to give some evidence for Gods existencei.e., that there is such a reality. Given what God must be, if there is a God, the theist needs to present the evidence, for such a very strange reality. He needs to show that there is more in the world than is disclosed by common experience. The empirical method, and the empirical method alone, such an atheist asserts, affords a reliable method for establishing what is in fact the case. To the claim of the theist that there are in addition to varieties of empirical facts spiritual facts or transcendent facts, such as it being the case that there is a supernatural, self-existent, eternal power, the atheist can assert that such facts have not been shown.
It will, however, be argued by such atheists, against what they take to be dogmatic aprioristic atheists, that the atheist should be a fallibilist and remain open-minded about what the future may bring. There may, after all, be such transcendent facts, such metaphysical realities. It is not that such a fallibilistic atheist is really an agnostic who believes that he is not justified in either asserting that God exists or denying that he exists and that what he must reasonably do is suspend belief. On the contrary, such an atheist believes that he has very good grounds indeed, as things stand, for denying the existence of God. But he will, on the second conceptualization of what it is to be an atheist, not deny that things could be otherwise and that, if they were, he would be justified in believing in God or at least would no longer be justified in asserting that it is false that there is a God. Using reliable empirical techniques, proven methods for establishing matters of fact, the fallibilistic atheist has found nothing in the universe to make a belief that God exists justifiable or even, everything considered, the most rational option of the various options. He therefore draws the atheistical conclusion (also keeping in mind his burden-of-proof argument) that God does not exist. But he does not dogmatically in a priori fashion deny the existence of God. He remains a thorough and consistent fallibilist.