Agnosticism is the philosophical view that it is unknown (or even, unknowable) whether any deities (god or gods) exist or not.
Some people who call themselves "agnostic" say that it is not possible for anyone ever to know if there are any deities or not. Other agnostics, though, say only that they themselves currently do not know if there are any deities.
Thomas Henry Huxley, the English biologist, coined the word "agnostic" in 1869. In 1889 he wrote "Agnosticism... is not a creed, but a method... the fundamental axiom of modern science... In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable".[1]
There are several different kinds of agnosticism:
Absolute agnosticism (also called hard agnosticism, closed agnosticism, strict agnosticism, strong agnosticism) is the belief that it is not possible to know whether a god/gods exists or not.
Empirical agnosticism (also called soft agnosticism, open agnosticism, weak agnosticism, temporal agnosticism) is the belief that at present there is not enough information to know whether any god/gods exists or not, but that we might find out someday.
Apathetic agnosticism is the belief that it does not matter whether any god/gods exists or not.
People often have difficulty telling agnosticism and atheism apart. Atheists do not believe in the existence of deities, and some say that they are sure that no deity exists. Some (perhaps most) atheists, though, say that it is up to theists (people who believe in a deity) to give the evidence for a god or to show why someone should believe in a god. They say that there is not enough evidence or a strong enough argument to believe any gods exist. So they reject belief that any exist. While agnostics think we cannot know for sure whether any deities exist, some agnostics do believe at least one deity exists These people are both agnostic and theistic—they believe at least one deity exists, but do not claim to know that to be true. Some people are both atheist and agnostic—they reject belief in any deities without claiming to know that deities do not exist. Some agnostics cannot decide whether to believe any deities exist or not.
Beliefs related to agnosticism
Ignosticism is the belief that the idea of god/gods does not have a good enough definition, so saying "god exists" or "god does not exist" does not mean anything.
Agnostic theism believes in the existence of one or more gods. They accept this is unknown or inherently unknowable.
Agnostic atheism is the view that a god/gods may or may not exist, but there is no good reason to believe they do.
Post-theism is the view that religion used to be important, but is not anymore.