Can an Atheist Rely on his Brain to be Rational?
Can an atheist rely on his brain to give him good reasons for his atheism? The late C.S. Lewis, a professor at Oxford University, did not think so. Lewis converted from atheism to Christianity and wrote extensively about why he found theism to be more rational. One of his reasons was that theism provided a basis on which to trust one’s mind to think logically and arrive at the truth. Atheism, on the other hand, implies that human brains are nothing more than the accidental products of a blind evolutionary process. As a result, brains, which are composed of physical matter, are subject to the laws of physics and chemistry, not logic. Lewis makes this point in the following passage.
Supposing there was 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 splashes arranges itself will give you a map of London. But if I can’t trust my own thinking, of course I can’t trust the arguments leading to atheism, and therefore have no reason to be an atheist, or anything else. Unless I believe in God, I can't believe in thought: so I can never use thought to disbelieve in God.
C. S. Lewis, The Case for Christianity, 1st Collier Books ed (New York: Collier Books, 1989), 395, Kindle.