Sonya Bahar and I have recently contributed to a large volume collecting arguments against the afterlife, edited by Michael Martin and Keith Augustine. William Hasker just reviewed it for NDPR. IMHO the review is not up to the usual NDPR standards.
Hasker dismisses the portion of the volume where our essay occurs as follows: “Non-specialists will find new and interesting details here, but the overall picture will be familiar to those who have followed the progress of the brain sciences. It is crystal clear that, in normal human life, mental function is dependent in an intimate and fine-grained way on brain function.”
Hasker does not engage in detail with any of the essays in the collection, with the partial exception of the essay by Augustine and Yonatan Fishman. His chief complaint is that while Augustine and Fishman correctly argue that the evidence that the mind depends on the brain impugns Cartesian dualism, there are other forms of dualism–such as Hasker’s “emergent dualism”–that, he claims, are consistent with such evidence.
As it turns out, Bahar and I explicitly argue against all forms of substance dualism. We don’t mention Hasker but we explicitly mention non-Cartesian dualism, of which his view is a version. In a nutshell, our argument is that mental functions take place within the brain in a way that rules out all forms of substance dualism. Neural activity is necessary for mental functions. Therefore, without a functioning brain, no mental functions are performed. (Hence, no mental life after brain death.)
One more point. Later in his review Hasker argues as follows:
If causal closure [of the physical] obtains, then evolutionary epistemology cannot be the explanation for human rationality. The reasoning is simple and compelling. If causal closure is true, then everything that happens in the brain has its complete explanation in prior physical events, no doubt mainly earlier brain-events. But this means that prior mental events play no role in determining the state of a person’s brain — and therefore, they play no role in the organism’s behavior. It follows, furthermore, that mental events and processes are irrelevant to behavior and are thus invisible to natural selection, which can only operate on physical structures and physical behavior. (emphasis original)
The only way that I can make sense of this argument is that Hasker begs the question by assuming that mental events are metaphysically independent of brain events–precisely the kind of claim that Bahar and I refute in our essay.