Atheism is simply the nonacceptance of a claim (theism) that lacks any supporting evidence. Not accepting a baseless claim is the anti-thesis of "faith" (ie. faith = accepting a claim without evidence).
Being agnostic is NOT a middle ground between theism and atheism. The break down is like this:
1) A god exists.
2) A god does not exist.
Theists accept #1 and reject #2.
Atheists reject #1 and can either accept or reject #2.
Gnosticism (for the purpose of this discussion) deals with what you claim to know. A gnostic claims knowledge about the truth of an assertion. An agnostic (literally "without knowledge") does not claim to have such knowledge.
The term "atheist" is very similar to the legal term "not-guilty". Declaring a person "not-guilty" does not mean they are "innocent". It simply means that there is insufficient evidence to declare them "guilty". Saying that an atheist must "prove" that no gods exist is like saying that you must prove your innocence in a court of law. Rejecting an assertion because it lacks supporting evidence does not require proving the opposite assertion.
You are of course 100% correct. I was using the terms in their literal, non-traditional meanings so your clarification is appreciated. However, too often I've found the baggage of words like "agnostic" obscures the discussion more than it clarifies it.
Literally, "gnostic" and "agnostic" refer to what you claim, or do not claim, to know. Given the general muddle of terms--"agnostic", "agnostic theist", "agnostic atheist", etc--I tend to find it more helpful to separate out the terms into core meanings. I believe doing so more clearly displays the positions, as you can plot the Atheism <-> Theism axis against the Agnostic <-> Gnostic axis. I would argue that this separation of claims-of-knowledge vs claims-of-god(s) is clearer than the simple Atheist <-> Agnostic <-> Theist positioning.
Being agnostic is NOT a middle ground between theism and atheism. The break down is like this: 1) A god exists. 2) A god does not exist.
Theists accept #1 and reject #2. Atheists reject #1 and can either accept or reject #2.
Gnosticism (for the purpose of this discussion) deals with what you claim to know. A gnostic claims knowledge about the truth of an assertion. An agnostic (literally "without knowledge") does not claim to have such knowledge.
The term "atheist" is very similar to the legal term "not-guilty". Declaring a person "not-guilty" does not mean they are "innocent". It simply means that there is insufficient evidence to declare them "guilty". Saying that an atheist must "prove" that no gods exist is like saying that you must prove your innocence in a court of law. Rejecting an assertion because it lacks supporting evidence does not require proving the opposite assertion.