"Agnosticism is the view that the truth value of certain claims—especially claims about the existence of any deity, but also other religious and metaphysical claims—is unknown or unknowable. Agnosticism can be defined in various ways, and is sometimes used to indicate doubt or a skeptical approach to questions. In some senses, agnosticism is a stance about the differences between belief and knowledge, rather than about any specific claim or belief.
Agnosticism can be subdivided into several categories. Recently suggested variations include:
Strong agnosticism (also called "hard," "closed," "strict," or "permanent agnosticism")
the view that the question of the existence or nonexistence of a deity or deities and the nature of ultimate reality is unknowable by reason of our natural inability to verify any experience with anything but another subjective experience. A strong agnostic would say, "I cannot know whether a deity exists or not, and neither can you."
Weak agnosticism (also called "soft," "open," "empirical," or "temporal agnosticism")
the view that the existence or nonexistence of any deities is currently unknown but is not necessarily unknowable, therefore one will withhold judgment until/if any evidence is available. A weak agnostic would say, "I don't know whether any deities exist or not, but maybe one day when there is evidence we can find something out."
Apathetic agnosticism (also called Pragmatic agnosticism)
the view that there is no proof of either the existence or nonexistence of any deity, but since any deity that may exist appears unconcerned for the universe or the welfare of its inhabitants, the question is largely academic.
the view of those who do not claim to know of the existence of any deity, but do not believe in any.
Agnostic theism (also called "spiritual agnosticism")
the view of those who do not claim to know of the existence of any deity, but still believe in such an existence.
the view that a coherent definition of a deity must be put forward before the question of the existence of a deity can be meaningfully discussed. If the chosen definition isn't coherent, the ignostic holds the noncognitivist view that the existence of a deity is meaningless or empirically untestable. A.J. Ayer, Theodore Drange, and other philosophers see both atheism and agnosticism as incompatible with ignosticism on the grounds that atheism and agnosticism accept "a deity exists" as a meaningful proposition which can be argued for or against. An ignostic cannot even say whether he/she is a theist or a nontheist until a better definition of theism is put forth." - Wikipedia, http://en.wikipedia.org/wiki/Agnosticism