Alvin Plantinga, professor of philosophy at Notre Dame, has for several decades been pressing the argument that it is literally irrational to be an evolutionary naturalist. Naturalism is the view that there is no God nor anything like God. It holds that nature is all there is. For the purposes of Plantinga's argument we can think of naturalism as being synonymous with atheism.
Plantinga argues that if evolution is true we have no reason to believe that naturalism is. He notes, for instance, that:
Richard Dawkins once claimed that evolution made it possible to be an intellectually fulfilled atheist. I believe he is dead wrong: I don't think it's possible at all to be an intellectually fulfilled atheist; but in any event you can't rationally accept both evolution and naturalism.
This is a claim that strikes many atheists as risible until they examine the argument that lies behind it. Once they do, the snickers cease.
Books and Culture has an essay by Plantinga in which he lays out his case in clear, easily comprehendable fashion. It's an important argument, one that both Christians and atheists should make themselves familiar with. Give it a few minutes of your time.
RLC
