Neurosurgeon Michael Egnor and I have been discussing the claims made in an article in Popular Mechanics last month in connection with our recent book, The Immortal Mind (2025). We ended up talking, as we often do, about the remarkable work of pioneer neurosurgeon Wilder Penfield (1891–1976) at the “Neuro,” the Montreal Neurological Institute-Hospital, especially with patients with epilepsy.

From the article: Penfield postulated that people often experienced certain emotions or conjured specific memories during seizures but were not overcome with abstract thought. That Penfield could not pinpoint the place where abstract thought exists in the brain, and that calculus is not conjured during seizures is proof, in Egnor’s eyes, of an immaterial mind distinct from the brain.

Michael Egnor: That’s just a gross misrepresentation. Penfield was not, specifically, trying to pinpoint where abstract thought comes from in the brain because nobody, including Penfield or anybody, thinks that abstract thought comes from a spot.

You can stimulate movement from the brain, you can stimulate arousal, you can stimulate perceptions, you can stimulate memories, you can stimulate emotions. But you can’t stimulate reason. That was Penfield’s point.

After hundreds of thousands of brain stimulations, and a total of 1,100 patients, he was able to stimulate an entire range of mental states. He was able to stimulate, specifically, movement, perception, memory, and emotion. He was never able to stimulate reason, or free will. That correlates roughly to what he called “mind action.”

And Penfield noted that that’s so weird. I mean, much of our mental activity every day is devoted to abstract thought. But neither a surgeon nor a seizure has ever been able to elicit abstract thought by stimulating the brain.

Now, one could say that abstract thought is complex, etc., you can’t do it by just a random stimulation. There’s no question that there’s some truth in that. But memories can be much more complex than abstract thought.

I can think that 1 plus 1 is 2. You know, a lot of 5-year-olds can do that. That’s not very complex, but that’s abstract thought. But people could have memories of detailed conversations that happened decades ago with all of the sensory input that they had at the time by a single stimulation of the temporal lobe. You can stimulate the temporal lobe, and a person has a memory of talking with their brother 40 years ago. That’s what Penfield did.

None of that was addressed. What they’re doing is making a caricature of Penfield’s arguments in a caricature of my arguments.

From the article: I asked Newsome about this. “It seems like a stretch,” he says. For one, more recent research has identified a location in the brain for numerosity, and some types of memory are thought to be diffused across the brain and not stored in a specific place—like the hippocampus, which handles episodic and spatial memories. And third, it was highly unlikely that a majority of people in the 1930s knew calculus.

Denyse O’Leary: Bill Newsome responded to the example of calculus as an instance of abstract thought that is not prompted by a seizure by saying that it was highly unlikely that a majority of people in the 1930s knew calculus. I got the impression that he was trying to get away from the main issue — the difference between abstract thought in general and other types of thought.

Egnor: What strikes me is the unbelievable lack of curiosity.

O’Leary: Well then, they’re leaving the field open for people who can better use curiosity.

Egnor: But the problem is they will spend their careers trying to discredit the people who are trying to better use it. The reason they’re ignoring it is not because they’re stupid. These aren’t stupid people. The reason they’re ignoring it is because it gets them into ideological territory in which they are deeply uncomfortable and they don’t want to find the truth.

As soon as these people start getting into these fascinating but tricky questions, if there’s anything that points away from materialism and away from atheism, they stopped dead in their tracks, and they spend the rest of their careers trying to discredit people who are willing to look at these questions.

Next: What do people who are conscious but lack a cortex demonstrate?