We cannot know with certainty if God or Christ exists. They COULD. Then again, there COULD be a giant reptilian bird in charge of everything. Can we be CERTAIN there isn't? No, so it's pointless to talk about.

I do not consider it an insult, but rather a compliment to be called an agnostic. I do not pretend to know where many ignorant men are sure that is all that agnosticism means.

Agnosticism is the position that the existence and nature of a god or gods are unknown or unknowable. Agnostics are often looked upon as wishy-washy fence sitters by both atheists and theists; however, most agnostics feel that it's intellectually indefensible to make a strong assertion one way or another. There is a frequent conflation between the idea of atheism ("there is no God") and agnosticism ("we don't know if there's a God") because the former might accurately express what one believes and how they live, while the latter would express their intellectual opinion if pressed.

The term was coined by English biologist T.H. Huxley in 1869, although the concept was expressed far earlier than that, going back to the Greeks around 450 BCE and even earlier mentions in the Hindu Vedas, written between 1700 and 1100 BCE. In modern times, the word agnosticism is used exclusively.

In theory, agnosticism is compatible with all but the most dogmatic of religious faiths, but in practice most agnostics are perceived as godless. Agnostics believe that while there is insufficient evidence to prove that there is a god, believing that there is not a god also requires a leap of faith (similar to any religious conviction) that lacks sufficient evidence. Simply put, agnosticism merely asserts that we lack the knowledge to determine whether or not God exists - in a sense, it differs from more explicit atheism by being a position based on a lack of knowledge, rather than a lack of belief. True agnostics would actually not fit on a hypothetical scale between theism and atheism as they would say the argument is unanswerable and could result in anything, almost like Schrdinger's cat but where the box can never be opened.

Most agnostics, however, can additionally be categorised depending on how their beliefs work out in practice, whether they're more atheistic or theistic. Agnostics may live and act as if there is no God and that no religion is correct, but shy away from the title "atheist" because of the expression of certainty implied. On the other hand, someone may consider themselves spiritual but not religious, or perhaps even nominally follow a religion, but identify as an agnostic in order to convey an honest doubt about the reality of it all.

Agnostic atheism holds that insufficient evidence exists to prove a god but also that logic is insufficient in overcoming the unknowability of the existence of a god. Agnostic atheists lean towards atheism as a sound null hypothesis, particularly in practice, but acknowledge that they could be wrong. The difference between atheism and agnostic atheism is subtle and may not be always be discernible, though agnostic atheists are generally more tolerant of the religious than more convinced atheists.

The distinction between agnostic atheism and atheism is further blurred if athiests are pressed for specifics about their beliefs. Okay, fine... lack of beliefs. It's clear that most, if not all, atheists are in fact agnostic atheists as rational-thinking people would certainly stop being atheists if they encounter evidence of God's existence that was sufficient for them. There is a prevalence of fundamentalist theists, but it is far rarer, if not impossible, to find fundamentalist atheists who would stick to their beliefs in the face of sufficient evidence.[1] Thus, if accepting the belief "there probably is no God; I'll act as if there's no God, but will change my mind if necessary" it's really just a matter of personal preference whether to identify as an "agnostic atheist" or just plain simple "atheist."

There is also agnostic theism, which maintains a belief in god, but acknowledges uncertainty regarding the characteristics of that god. Some theist agnostics are also Deist, believing that God created the universe but is irrelevant to the workings of it (essentially, they assert that we may or may not know whether God exists but it matters not anyway because of God's role to play, or lack thereof, in universal affairs). Believing agnostics often identify themselves as fideists, a term coined by Martin Gardner (a theist himself) for people who choose to believe in God because it comforts them and not for intellectual reasons.

Like pretty much every other philosophical definition ever invented, agnosticism has also been split into so-called "weak" and "strong" positions.

Continued here:
Agnosticism - RationalWiki