In this post, I will expand on my earlier posts “Free Will” and “The Experience of Free Will.” Those posts presented positive arguments for the existence of free will, and this post will present a negative argument against determinism.
Let’s first think about the claim that the determinist is making. The determinist typically claims that our minds operate by means of mechanical cause and effect relationships, like any other chemical process. One way of spelling this out is to say, with Daniel Dennett, that the mind is a collection of different, basically independent neurological processes including reason, memory, and perception. These processes in turn reduce to yet simpler processes, which reduce yet more until we reach neurological reactions so simple that they are not recognizable as being conscious. There is no one “in charge” of your mind, on this view, just billions of neurons operating according to the blind laws of physics and chemistry.
Suppose this were true. Clearly, in that case, all of our beliefs would be the product of deterministic chemical and neurological reactions. I would just believe that I enjoy programming computers because the chemical reactions going on in my brain had percolated in that belief. But if that is true, then there is no reason to trust any of my beliefs.
Suppose I want to know what book is on my desk, and I decide that since the book looks blue, it must be my book on John Stuart Mill. The problem with this strategy is that I also have a number of other blue books in my possession, so the fact that the book is blue doesn’t prove that it is my book on John Stuart Mill. The evidence I have under-determines my conclusion. This is the position that the determinist is in with respect to his beliefs – there is a very real possibility that he is being tricked by his brain into holding beliefs that are false, and he has no way of finding out whether or not this possibility is actually the case. He might hold his beliefs if they were true, granted, but he might also hold them if they were not true. But this would also apply to his belief in determinism, so his belief in determinism is self refuting.
If we have free will, then we don’t get into this trouble, because we have direct control over our belief forming process and can make sure that it is based on evidence and logic at every step. If I am solving a problem for my math class, I can be confident of my conclusion because I have done a number of examples of the same type of problem before and I have consciously guided my thought processes in such a way that I applied the rules of inference correctly. This doesn’t mean that I’m infallible, but it means that my mind is generally pretty reliable. By contrast, if determinism is true, there is no reason to think that an argument that seems reasonable to me is any more likely to be true than one that doesn’t seem reasonable.
Now, the determinist might say that he can escape my argument by asserting that his belief forming process is guided by reason. This overlooks the fact that the belief that the determinist’s belief forming process is guided by reason is itself subject to the skepticism that determinism entails. If determinism is true, it’s quite possible that the determinist is deceived about his belief that his belief forming process is guided by reason, for the reasons I have given.
That concludes my argument that determinism is self refuting. I have another negative argument against determinism, which I may give in another post.