When I first got Plantinga’s latest book, I was a little unsure of what to say about the version of evolutionary argument against naturalism (EAAN) he presents there. I’ve long been irked by Plantinga’s apparent lack of curiosity about what scientists who work on the evolution of the mind would say about his argument. On the other hand, in the latest version of the EAAN, the half-baked thought experiments are gone, and instead we get a goofy claim about what “materialism” entails:

Suppose materialism were true: then, as we’ve seen, my belief will be a neural structure that has both NP [neuro-physiological--Hallquist] properties and also a propositional content. It is by virtue of the NP properties, however, not the content, that the belief causes what it does cause. It is by virtue of those properties that the belief causes neural impulses to travel down the relevant efferent nerves to the relevant muscles, causing them to contract, and thus causing behavior. It isn’t by virtue of the content of this belief; the content of the belief is irrelevant to the causal power of the belief with respect to behavior (p. 336).

Plantinga argues that therefore, if materialism is true, then there’s no reason for evolution to produce reliable belief-forming mechanisms, and therefore it’s unlikely that evolution would produce reliable belief-forming mechanisms. This strikes me as utterly bizarre. As far as I can tell, it makes no more sense than saying that if materialism were true, it is by virtue of the arrangement of subatomic particles that our digestive system digests food, and therefore whether or not those particles are arranged into a stomach, intestines, etc. is irrelevant with respect to digestion, and therefore evolution is unlikely to produce those organs.

My guess is that that is what most non-eliminative materialists would say in response to Plantinga. In fact, hardcore non-reductive materialists like Hilary Putnam would say that the higher level explanation is crucial, and the lower level explanations aren’t even really explanations. Plantinga shows no curiosity about any of this; there’s not the slightest mention of how materialist philosophers might respond to his central claim. And that looks like a bigger problem than ignoring evolutionary biologists.

But… I recently (more recently than I read Plantinga’s book) re-read Stephen Pinker’s How the Mind Works, which talks about the cognitive revolution in psychology, which happened decades ago, and which in the mind of many psychologists has demystified things like beliefs and their relationship to the brain.

Because of this, I don’t think there’s any reason to see the relationship between the brain and beliefs as any less a scientific issue than the relationship between atoms and macroscopic objects. And it means that by ignoring what materialists might say about his argument, Plantinga isn’t just ignoring other philosophers, he’s also ignoring scientists. As I explained in my previous post, that really shouldn’t be acceptable anymore.