Victor came up with an argument against naturalism that is stunningly bad. So bad, in fact, that it could easily have been the product of a grade-school student rather than a PhD philosopher. This is worthy of examination, simply because it illustrates a number of blunders that should be avoided by anyone who wants to make a serious logical argument. This is what he said:
The evidential relation is not a physical relation. So if physicalism is true, evidence never has anything to do with what anyone believes. On that view, only spatial, temporal and causal relations have anything to do with anything that goes on in reality. So rather than being the correct conclusion of evidentialism, naturalistic materialism actually makes evidentialism impossible. If theism is true, then it is possible for beliefs to be based on evidence. Otherwise, it's metaphysically impossible. - ReppertPerhaps we should give Victor the benefit of the doubt, and assume that he's making a parody rather than a serious argument. Let's take it step by step.
Use obscure wording.
It's hard for someone to argue against you if they can't figure out what you're saying in the first place. What exactly is "the evidential relation"? Several people commented that the argument was not worded clearly. It was a fellow theist, Ilíon, who shed some light on the meaning. He explained that when evidence is presented, one must make logical inferences from the evidence to some conclusion about what that evidence entails. And of course, he maintains that any logical process is a non-material process.
Today, "one billiard ball hitting another" may, via physical cause-and-effect, cause you to respond "two" to the question, "How much is one plus one?" Tomorrow, "one billiard ball hitting another" may, via physical cause-and-effect, cause you to respond "applesause" to the same question. Which response is correct? Is either response even an answer in the first place?This seems to be a reasonable way to interpret Victor's statement. But that brings up step two in the process of making a bad argument.
Make unsubstantiated assumptions
So any logical process is non-physical? On what basis is such a claim made? I understand that theists believe that logic derives from the mind of God, but does that translate to logic being non-physical? We know that computers perform extraordinarily complex logical processes using purely physical means. We also know that when adding one and one, the answer doesn't arbitrarily change from "two" to "applesauce". Only in the absence of any physical basis for logic would it be possible to conclude that one plus one is applesauce, because there would be no way to ground logic in reality.
The notion that logic is anything but physical defies observation. Logic is nothing more than a recognition of physical reality. Children begin to learn logical relationships very young, even before they can express them in language, by observing the physical world around them. How do they do their first problems in addition? By counting on their fingers - a physical process. How do they come to accept the truth of any logical rule or axiom? By using physical examples to convince themselves that these rules always apply. Only later in their cognitive development do they gain the ability to abstract - to separate logical rules from their physical basis. Only then might it be possible for someone to claim that logic is not physical. But they ignore the reality. Logic just expresses rules about the way the physical world works.
Ignore the implications of your own argument
The presumption of the non-physical nature of logic is a theistic assumption that denies physicalism. How, then, is it possible to assume physicalism is true as part of the argument without also assuming what physicalism entails? Victor says "if physicalism is true, evidence never has anything to do with what anyone believes". Huh? What? If physicalism is true, then evidence has everything to do with what we believe. It is only on the assumption that physicalism is false that we could claim a chasm between physical evidence and beliefs inferred by logic. What Victor has done is to start out by making a blatantly theistic assumption that denies physicalism, and then stick to it even when his own argument assumes that physicalism is true.
Bad logic and bad assumptions make bad conclusions
So Victor wraps it up by concluding that physicalism makes it impossible to believe anything based on evidence, and theism is consistent with evidence-based belief. How bizarre. It is exactly the opposite of what we see every day. Physicalists don't believe in gods, because the physical evidence doesn't indicate the presence of gods. Theists believe in gods despite the physical evidence. It is only through the use of tortured logic and reality-defying assumptions that someone could come to such a ridiculous conclusion.
And Victor should be utterly ashamed to have this argument associated with his name and his PhD.