C.S. Lewis was an atheist for many years and had a big question:
If a good God made the world why has it gone wrong? And for many years I simply wouldn’t listen to the Christian answers to this question, because I kept on feeling, ‘whatever you say and however clever your arguments are, isn’t it much simpler and easier to say that the world was not made by an intelligent power? Aren’t all your arguments simply a complicated attempt to avoid the obvious?’ But then that threw me back into those difficulties about atheism which I spoke of a moment ago.
My argument against God was that the universe seemed so cruel and unjust. But how had I got this idea of just and unjust? A man doesn’t call a line crooked unless he has some idea of a straight line. What was I comparing this universe with when I called it unjust? If the whole show was bad and senseless from A to Z, so to speak, why did I, who was supposed to be part of the show, find myself in such violent reaction against it? A man feels wet when he falls into water, because man isn’t a water animal: a fish wouldn’t feel wet. Of course I could have given up my idea of justice by saying it was nothing but a private idea of my own. But if I did that then my argument against God collapsed too – for the argument depended on saying that the world was really unjust, not that it just didn’t happen to please my private fancies. Thus in the very act of trying to prove that God didn’t exist – in other words, that the whole of reality was senseless – I found that I was forced to assume that one part of reality – namely my idea of justice – was full of sense. Consequently atheism turns out to be too simple. If the whole universe has no meaning, we should never have found out it has no meaning: just as if there were no light in the universe and no creatures with eyes we should never know it was dark. Dark would be a word without meaning.
(The Case for Christianity, pp. 34-35. Italics in original.)