Over a year ago I wrote a post differentiating the agnostic and atheistic positions. I said that in the absence of empirical proof of the existence of god, the evidence for and against god is weighed. The agnostic thinks the evidence about even, and the atheist thinks it's weighted in favor of there being no god. But I recently thought about a recent post of mine regarding Christopher Hitchens' definition of atheism, and so I decided to create a scale with nine levels of belief and disbelief in god ranging from strong atheism, to strong theism.
On my scale shown above, the moderate atheist can stop short of saying "There are no gods," but can say "There almost certainly are no gods. I therefore don't believe in any gods." In other words, given the weak evidence for god, and the powerful explanatory power of science, moderate atheism can affirm a warranted belief in the ability of science to naturally explain the existence of everything in the universe, including the universe itself, without the need for a deity.
Imagine this question posed to a non-believer: Are you an atheist that asserts the proposition that god does not exist, or do you simply withhold belief in god in the way the agnostic does?
This is an interesting question because it seems to accuse the moderate or weak atheist of really just being an agnostic. Does an atheist have to confidently assert that god does not exist? To me really anyone who falls short of at least saying "I believe in god" is an atheist. Since the agnostic doesn't actively believe in god, he or she is technically an atheist.
But let me answer this question using an analogy. Imagine a friend told you they saw Bigfoot outside their bedroom window the other night. Your immediate reaction would probably be disbelief, despite your friend insisting he saw Bigfoot. Most of us, including myself, would require some good evidence to prove that Bigfoot was really lurking outside your friend's bedroom. And in the absence of such evidence, you could rationally conclude that there was no Bigfoot, and that your friend either is lying, saw something that wasn't there, or saw something like a man in a Bigfoot suit. In other words, in the absence of evidence, the default position is disbelief.
I treat the existence of god the same way. In the absence of empirical evidence that cannot be explained by science under naturalistic causes, the default position is disbelief. This is especially so when the claim being made requires the supernatural. That means I say "I don't believe in god" but I don't say "I know god doesn't exist". Proof of non-existence is not required in order to not believe, all that is needed in the case of god is a plausible natural explanatory alternative. So therefore on the scale above, I would generally fall under moderate atheism because I do not assert that "there is no god," since it cannot be proved.