Theists: What is the most compelling argument you have heard for Atheism?

[Whateverist]

But how else can we ever judge a claim except by the conceptions we've acquired up to that point? For a claim that by definition for a miracle is impossible by all prior understandings, it is very hard to say in advance what the standard should be. All I'm sure of is that connecting the dots for the natural aspects of the claim will in no way bridge the way to vouchsafing the part which is alleged to be 'miraculous'.