This is a problem I have written about before: if matter is the only thing that exists then every single thought and action is the result of physical reactions over which we have absolutely no control. It would mean we think and act the way we do because that’s the way the chemicals within us have reacted. We would be, as one atheist physicist said, “collections of elementary particles interacting according to the laws of physics, and if I was able to write down every single particle in my body, and if I had [sufficient] computational ability, I could predict what I would do.” (Notice, he assumes he would have the freedom to direct his mind to do the calculations! If his materialism were correct, he would just have to wait and see how the matter in his head reacted and what it made him do.)
My friend didn’t want to admit this was what his worldview entailed, so he retreated to ignorance and said, “I don’t know how we have rationality, and that’s one of the things about atheists that makes them different from Christians, we aren’t afraid to say we don’t know.”
Well, I’m not sure where he got the idea that Christians are afraid to say we don’t know. Throughout the conversation he was asking me all kinds of questions about God that I was very willing to admit I didn’t know – he was asking me why God allowed so many species of animals to go extinct and why God allowed certain events to happen. I told him I could have a guess, but I didn’t know, and what’s more, the Bible repeatedly states (and common sense would agree) we can’t know all the reasons God has for what He does.
So I have no problem with saying I don’t know, or with someone else saying it … if it’s genuine. But I wanted to push a bit with my friend. If his materialistic view of the world is true then there just is no rationality – your thoughts and actions are the results of mindless processes over which you have no control. It’s a cop-out to say, “I don’t know how we have rationality.” If someone is a materialist, there’s no new information that is going to account for genuine rationality and be consistent with materialism. There’s no point proclaiming ignorance as a virtue here. The materialistic worldview cannot, and never will, account for rationality, and yet we know that we are rational.
"The materialistic worldview cannot, and never will, account for rationality, and yet we know that we are rational."
A collection of chemicals fizzing and reacting in someone’s skull is not going to result in calculations that allow a man to go to the moon or a rover to land on Mars. It will not produce works of prose and poetry, art and music. It will not result in arguments about rationality, materialism and God!
So rather than bury his head in the sand, my friend should face the facts – materialism is bankrupt to explain reality, and he knows it.