Atheists are quick to remind us that any positive claim to knowledge should be backed by evidence if it is to be rationally believed. Without such evidence for God, a person is rationally justified in lacking belief in God and therefore should be considered an atheist (called "weak atheism") even without arguments to disprove the existence of God. As I see it, this reasoning is right. Rational beliefs ought to be supported by evidence. Of course, theist philosopher, Plantinga has made some interesting points to suggest that knowledge of God is "properly basic" and known intuitively without need of evidence. But as I see it, Plantiga’s arguments can simply be seen as a kind of potential evidence for rational belief in God. So without evidence of any kind (either a priori or a posteriori), it seems one would be justified to not believe in God. Even though I recognize this point, I think it’s worth offering a point of caution about the implications of "weak atheism".

First of all a weak atheist can’t also think to herself, "God doesn’t exist" without having good evidence to support this claim to knowledge. (I’m considering arguments such as "absence of evidence is evidence of absence" as potential evidence against God that would need to be offered). So a weak atheist is really a lot like an agnostic in that she neither affirms nor disconfirms that God exists. Basically, weak atheists don’t claim to have any knowledge about whether or not God exists. I make this point only because often I get the impression from reading atheist literature that there is this unconscious tendency to claim weak atheism in order to shift the burden of proof on the theist, but then to actually believe more than that claim, namely, to believe that God doesn’t exist. Before saying a word or thinking a thought, the burden of proof belongs as much to the atheist who denies God as to the theist who affirms God.