Coyne recently gave a talk at Williams University in Maryland where he elaborated on this consequence of a materialist worldview. Neurosurgeon Michael Egnor comments on Coyne's views in a piece at Mind Matters where he opens his critique with this:
When the history of modern materialism is written, it will be a catalogue of almost incomprehensible folly. The striking irony is that many of the most strident claims by materialists are not merely empirical and logical nonsense; much of materialism is self-refuting.It's self-refuting, Egnor argues, because if all that's going on when we think or when we choose is electrochemical processes in the neurons in our brains, how can those processes be true or false? A chemical reaction is neither true nor false, it has no truth value at all.
Thus the claim that "materialism is true" is nonsense. It's what philosophers call a category mistake. Truth is a property of propositions, not chemical reactions.
Egnor employs this same criticism against Coyne's claim that our choices are not free but are determined by physical causes:
[T]he assertion that materialism is true is the implicit denial that materialism, or anything else, can be true.It might be more correct to say that if a materialist claims either that materialism is true or that determinism is true, the objective truth value of the claim is purely coincidental, arising as it does from a neurochemical matrix in the brain which does not possess the ability to intentionally generate truth claims. In other words, it might actually be a true description of the world, but if so, it's just a lucky coincidence that it's true.
Coyne’s assertion—determinism is true and free will is an illusion–is a proposition. That is, he has made a statement that can be true or false. If Coyne is right, then his own denial of free will is wholly the product of physical and chemical processes—action potentials, neurotransmitters, and the like. But physical processes are not propositions.
The secretion of dopamine at a synapse is neither true or false. It is merely a secretion of dopamine.
Thus, Coyne’s claim that his own ideas are wholly determined by physical and chemical processes is inherently a claim that his ideas have no truth value—they are neither true nor false. Coyne himself, and his (material) “ideas,” are just chemicals in motion.
So when Coyne denies free will based on his belief in determinism, he is telling us that his claim lacks truth value. And in that, and that only, he is right.
Whether anyone in Coyne's audience was persuaded to believe that it's true or not is not because Coyne's claim corresponds to the way the world is but because the neurochemical matrix in the listener's brain produced a decision to believe or disbelieve.
In any case, there's something peculiar about a university professor presenting a lecture in which he implicitly asserts that the position for which he's arguing, the claim he wants his audience to believe, is really neither true nor false, yet that's pretty much what Coyne and other determinists do.