I think one of the most common problems I have run into with Christian apologetics has been that of talking to people of different worldviews. There are two main worldviews that are incompatible with Christianity, and I have approached many times. The first, a worldview typically found among scientists is that of naturalism. Here briefly, I want to present an argument against naturalism and then offer advice to any students of science of how one can have a philosophical worldview which is both consistent with science and theism (or at least Christianity).
This argument will be based mostly on an argument presented by C.S. Lewis in the first 5 chapters of his book Miracles. Perhaps the best way to approach such a difficult topic is to define one’s terms. There are two main kinds of naturalism, one of which I think is necessary in order that science can function, and the second which is philosophical and applies far beyond scientific study. The first is called “methodological naturalism” or “scientific naturalism”, and it, in short, is the practical assumption in science that God is not going to intervene in creation and that things happen by purely natural means. Often, scientists and philosophers try to step beyond this and into philosophical or ontological naturalism which is the view I will be discussing here. Naturalism, as I’ll be talking about it, is the belief that only nature exists: that no God nor anything like Him exists. This argument (being an argument for dualism as well) would also apply to theists who deny an immaterial mind and hold a materialist view of humans (often in Christianity the mind is considered a function of the soul, and so would be immaterial, in naturalism the mind would be a function of the brain).
My presentation may differ from Lewis’s in some respects, and I recommend that anyone who finds this argument intriguing read his book or a book by Victor Reppert entitled, C.S. Lewis’ Dangerous Idea. Hopefully if I stray from Lewis it won’t be to the detriment of the argument.
The argument, simply put, goes something like this:
There are two ways to answer the question, “Why do you believe that?” The first is that one believes due to a physical process or neural event occurring in the brain, and would be a physical description. The second would be a rational answer which appeals to logical principles. The best way to bring this distinction forward is probably by way of example.
Let us pretend that four year old Sally thinks her favorite doll was moved by her brother. If one were to ask Sally why she thinks this she could answer in two different ways. First, she could say, “Well, I underwent a neural process where neurons in my brain fired and atoms moved in the grey matter of my brain resulting in my conviction that he had moved my doll”, or she could answer in the manner we would hope a four year old would answer, “Well, I saw him come in here earlier and when I got back my doll was missing. He’s the only one who went into my room, so he must have moved it.”
Now, upon reflection, one will notice that there is something which separates these two answers: while the first appeals to physical descriptions (in and of itself not bad), the second appeals to logical principles. We will call the first kind of answer, “causal relations” in that it answers the question”why?” by means of causal descriptions and we will call the second “ground-consequent relations” in which “grounds” are the reason for belief and “consequent” represent the conclusion. In this circumstance “grounds” would be the brother entering Sally’s room, his being the only one to enter Sally’s room, and the fact that the doll has come up missing. The “consequent” will be the conclusion that he took the doll.
Any good answer must account for ground-consequent relations. For example, let us examine a simple argument based on a basic form of reasoning called modus ponens.
A basic modus ponens argument would go like this:
1. If one is human, then one is a mortal.
2. Bill is a human.
3. Therefore, Bill is a mortal.
Now, this argument is obviously valid. We can easily see that if the first two statements are true, then the third must also be true. This is also an example of ground-consequent relations in which the grounds imply the consequent (that one’s being human implies one is mortal). And any argument must enable conclusions to be based on one’s recognition that the conclusion logically follows from the premises. This poses no problem for the Christian theist as she believes that one is a rational being endowed by God with a certain amount of rationality. But, how does this relate to a naturalist worldview? Does this present any problems?
Well, upon reflection, it does. In naturalism, a human being is a material object. The mind is a function of the brain, and the brain is governed by the laws of physics. But if mental processes are governed by physical laws, what place to logical principles have in my belief formation? For instance, if the naturalist were to make the above argument, she would expect me to believe it based on the fact that it’s obviously true. But how can she? Since, in naturalism, my beliefs are determined by physical particles moving according to the laws of physics, how can my recognition of a logical principle change the motion of those particles? In reality, my brain matter would have no more choice in what beliefs to form than water would have to run uphill, so how is it that if one believed Bill is immortal, they can then cause their brain matter to move in a manner based on a logical recognition and not physical laws so as to draw a different conclusion? How can the immaterial cause of “recognition” create a change in the motion of material particles?
In naturalism it appears this cannot happen. The motions of atoms in one’s brain would be determined by laws and any talk of changing their paths by means of something non-physical (such as logical laws) seems nonsense. Thus, in naturalism we reach the ultimate difficulty that reason itself cannot be accounted for. And if reason itself cannot be accounted for, then neither can it’s convictions. Thus, so long as naturalism relies on reason to be accepted, it is a self-refuting worldview. By accepting arguments in favor of it, one has accepted that no argument is sound. But, if one argues that no argument is sound, they have put themselves in an awful predicament. If one were to succeed in proving that no argument is sound, they will have proven that their own argument fails. If they do not succeed in proving that no argument is sound, then there will be no reason to think that no argument is sound. By succeeding they refute themselves, by failing they never establish their claim.
In the end, I find naturalism to be self-refuting insofar as it is based on reason. I, therefore, present the view of Christian theism, in which man’s mind is immaterial and not subject to natural laws, but can recognize logical and mathematical truths, while the brain may still be governed, as a physical entity, by the laws of nature.