Atheism and Human Thought

“There are all sorts of different reasons for believing in God,” writes C. S. Lewis in The Case for Christianity, “and here I’ll mention only one. It is this. Supposing there were no intelligence behind the universe, no creative mind. In that case nobody designed my brain for the purpose of thinking. It is merely that when the atoms inside my skull happen for physical or chemical reasons to arrange themselves in a certain way, this gives me, as a by-product, the sensation I call thought. But if so, how can I trust my own thinking to be true? It’s like upsetting a milk jug and hoping that the way the splash arranges itself will give you a map of London. But if I can’t trust the arguments leading to atheism, [I] have no reason to be an atheist. . . . Unless I believe in God, I can’t believe in thought; so I can never use thought to disbelieve in God.”