I found this to be a great defense of C.S. Lewis’s argument against naturalism. To state briefly, Lewis’ argument is that naturalism is self-refuting because it denies the very reasoning capacities that are needed to conclude that naturalism is true. How does it do this? In short, it collapses all reasoning into mere Cause and Effect, denying Ground-Consequent reasoning. Every state in the universe, including mental states, is just a result of the previous state and so forth. Person A votes for Barack Obama because of all the physical matter interactions in her brain and her environment, relegating rational inference to being only a smokescreen hiding these true physicalist explanations. What if Person A states that she is voting for Obama because she thinks his healthcare plan will greatly reduce unnecessary suffering in America? She may be thinking to herself, if I vote for Obama, then suffering will decrease. At hearing this the naturalist would have to jump up and look to evolutionary genetics, sociological theory, and the other ‘soft sciences’ for clues to the real explanation. The decision was perhaps due to her genes and/or environment. This in turn breaks down to the purely physical interactions of the ‘hard sciences,’ which turn from psychological explanations to purely physical ones. ‘She grew up in a very liberal Democratic area and her parents are Democrats’ turns to ‘These neurons in her brain fire when she thinks of Obama…‘ The chain of cause and effect, like a long line of dominoes, has been falling since the Big Bang ensuring from the beginning of the universe that she’d support Obama.
You can see the problem now for the naturalist who holds to a set of metaphysical beliefs such as, 1) The physical order is causally closed. 2) atheism, etc. Under the naturalist’s own schema though, these beliefs cannot be held up. Any rational justification could be debunked just as he debunked the Obama supporter above.
Theism can account for both Cause-Effect and Ground-Consequent relationships. Being created in the image of God we are endowed with reason. Person A could really be supporting Obama at bottom because of her rational beliefs. If one is to contend against her belief, one must do so on the Ground-Consequent level, as is usually (or perhaps one should say ’hopefully’) done in political debate. They must either show that her reasoning is invalid or unsound. If this argument is correct than basic explanations must include reasons as well as what Reppert calls, “the blind operation of nature obeying the laws of nature.” (Pg. 53)
Now that this argument is stated and expounded a bit I will move onto Elizabeth’s Anscombe’s criticism. There is obviously more to Reppert’s book than this but I want to touch only upon what I think to be the most significant/interesting ideas.
One significant criticism Anscombe employs is what Reppert calls a “paradigm case argument.” She basically asks why one should take Lewis seriously if they are a naturalist since if naturalism is true then Lewis’s distinctions between valid and invalid reasoning would be meaningless. By asking, what if all our reasoning is invalid is really to ask a meaningless question because in the naturalist paradigm such ideas of ‘true’ and ‘false’ are defined differently than the definitions Lewis used. In essence such people are playing a different language game. It would be like if a believer in Descartes’ Evil Deceiver tried to convince someone not of that belief that everything they believed was false. There would be communication difficulties to say the least.
Reppert gets around this by claiming that as a skeptical threat argument, the paradigm case objection would be valid, but if one changes the argument to a more modest argument to the best explanation then one gets around this objection. Rational inference must be assumed to exist for any discussion to take place. This conflicts with naturalism because under naturalism reason explanations are always reduced to physical explanations which are nonrational. Therefore, naturalism should be rejected as false.
Anscombe’s last line of attack claims that reason-explanations are noncausal. Lewis is quite correct here to object. If Person A votes for Obama because he gives him warm feelings inside than that shows that her claimed rational reasons for supporting him are if not untrue in themselves, then untrue when it comes to her own decision-making. A person cannot be thought of as rational unless their rational claims are causal over and against what is happening psychologically. Reppert states, “For example, if a prosecutor were to believe that the defendant was guilty on the basis of DNA evidence, what would we think of him if it turned out that he hated the defendant so much that he would believe in his guilt regardless of the DNA evidence?” (Pg. 64)
I would go onto Reppert’s six arguments from reason but I am tired and I frankly do not have a sufficient understanding of the philosophy of mind to consider them critically. After reading most of Lewis’ works and Reppert’s defense of him, I am confident that this argument is sound. Now, I am curious about what the ‘other side’ would say in response the Argument from Reason.