I read the other day that the common epistemological definition of knowledge is justified true belief. Let’s take a look at atheism through this definition.
Atheism is a ‘lack of belief.’ Therefore if knowledge is belief, atheism can’t be knowledge, because it constitutes no belief. So we start off 0/1.
Justified means having valid reasons to believe. The absence of evidence is not evidence of absence. But as an atheist, you don’t actually believe, you simply ‘lack belief’. If you had reasons to lack belief, your position would be that God doesn’t exist, not that you simply lack belief in God.
‘True’ would only be applicable if the atheist position was ‘God doesn’t exist.’ Or that the claim ‘God exists’ is false. The only sense where you could consider the atheist position as true is by looking at it as self-affirming. Something like ‘it is true that this atheist doesn’t believe in God.’ But that just doesn’t get us any closer to whether or not God exists.
So if we can define knowledge as justified true belief, atheism fails on all counts. If atheism is framed as a rational pursuit of knowledge, it fails to answer the only question that it attempts to answer.