I would like to attempt to clear up a common misconception espoused by many theists I've come across. It starts with the definition of "Atheism", and ends up with theists claiming that atheism takes just as much faith as theism(if not more), and/or how atheist also bear a burden of proof.
Atheism, in a general sense, is the lack of belief in a god. That's it. It tells you nothing else about the person. It's not a worldview, dogma, way of life, belief system, it contains no tenets, and it only addresses one question. That question is, "Do you believe that a god exists?". Many theists insist that atheism is the assertion that no gods exist. This is not the case. There is a big difference between saying that you do not accept the claim that a god exists, and asserting that a god does not exist. If you insist on using that definition, then it does not apply to most atheists. The only point it serves in refusing to acknowledge the definition used by most atheists, is to set up a strawman. I'll only be referring to those that actually have this misconception and not those who do this because of dishonesty.
Since this seems to be a topic of confusion for so many people, I will try and break this down. In regards to the question of whether or not a god exists, there are two possibilities. 1.) God Exists. 2.) No God Exists. Those are about what is actually true. They are truth statements. One of them must be true, and it can't be neither or both. But your belief in regards to each of those positive assertions is a different matter.
Claim 1: God exists
A.) I believe this claim
B.) I do not belief this claim
Claim 2: No God Exists.
A.) I believe this claim
B.) I do not believe this claim
Not accepting one of those claims does not mean you must accept the opposite claim. For instance, you can not accept the claim that god exists, but also not accept the claim that no god exists. This is where most atheists would reside. They do not find sufficient evidence to support either claim.
You can think of this in terms of a trial in a court case. The defendant is either guilty or innocent (the truth statements). But the jury is only deciding on guilt(god's existence). Innocence(god's non-existence) plays no part. A vote of "not guilty" does not necessarily mean the juror thought the defendant "innocent". Just that the prosecution did not provide sufficient evidence for a guilty verdict. The defendant is presumed innocent until sufficient evidence is provided to show guilt. Atheists find god "not guilty" of existing. Another example would be if I were to claim that Central Park contains an even number of blades of grass. Would you believe me? No. But does that mean you then must believe that Central Park contains an odd number of blades of grass? No. While it's true that one of those claims must be true, you are perfectly justified in not accepting either claim due to insufficient evidence to support either.
Atheism only deals with Claim 1, not Claim 2. Keep in mind, there is no middle ground with regards to your belief of these two claims. You either believe the claim, or you do not. It is not logically possible to say otherwise. The default position is to not believe the claim. So if you say "I don't know", or "I refrain from answering", then you are in fact answering "I do not believe the claim". Answering B to Claim 1 bears no burden of proof. It is not a positive assertion.
Atheists answer B to Claim 1. Theists answer A. Theists answer B to Claim 2, but so do Atheists. Unless they are a Strong Atheist, Anti-Theist, Gnostic Atheist, or any other subset of Atheism that makes the positive assertion that god does not exist. It is important to note however, that most Atheists do not make that positive claim..
I also think it necessary to briefly talk about the definitions of god. It is important to have our terms defined before even getting into such discussions of believing/disbelieving claims about one. Speaking for myself for a moment, I do not accept either claim about god. But in this sense, I'm using the most broad and general definition of god, resembling that of deism. An entity that set the wheels in motion to cause the universe. I cannot assert that this doesn't exist, although I don't find it necessary to explain anything. But if you define god as Yahweh of the bible who created the universe 6,000 years ago and is omniscient, omnibenevolent, and omnipotent, then that is a completely different story. I have many objections to that particular god existing, and I would be happy to back up the positive assertion that it does not exist.
Finally, I'd like to address how disbelief in the existence of a thing is the null hypothesis, or default position. This is how we address existential claims. You can easily see the problem if one were to suggest we believe all existential claims until proven wrong. That would lead to absurdities. It doesn't take just as much faith to disbelieve in the existence of the loch ness monster as it does to believe it. It doesn't take any faith at all. The same reasoning applies to gods.
