In the recent debate between neurosurgeon Michael Egnor and philosopher David Papineau, “Atheist Philosopher and Christian Neurosurgeon Debate Materialism” at Theology Unleashed, there was sort of digression at 49:30 on the nature of thought. Dr. Egnor talks about what he learned from his experiences with treating epilepsy and Dr. Papineau responds.

Note: Dr. Papineau is a “physicalist.” On that view, “the mind is a purely physical construct, and will eventually be explained entirely by physical theory, as it continues to evolve.” (Philosophy basics) He is considered to be one of the best defenders of naturalism (nature is all there is), often called “materialism.”

Michael Egnor: There are three metaphysical questions that I think can be answered in an inferential way, by neuroscience, about the mind-brain relationship. The first question is, is the mind metaphysically simple? That is, can it be divided into parts? The second question is are there aspects of the mind that are immaterial? And the third question is, is free will real? [00:50:00] The immaterial one is a good one to start with.

Wilder Penfield, who was a pioneer in seizure neurosurgery in the mid-20th century, found that when he did “awake craniotomies” to treat seizure patients, these patients were fully awake during the surgery, with local anesthesia so they felt no pain (and I’ve done the same kind of surgery) that he could not evoke any abstract thought or intellectual content on stimulating the brain. He could invoke movement … he could evoke sensations, he could evoke emotions, and he could evoke memories. He could not evoke abstract thought.

Note: Awake craniotomy “Awake brain surgery, also called awake craniotomy, is a type of procedure performed on the brain while you are awake and alert. Awake brain surgery is used to treat some brain (neurological) conditions, including some brain tumors or epileptic seizures.” Why? “Surgery while you are awake reduces the risk of damaging critical brain areas that control speech and other skills.” – Mayo Clinic

Michael Egnor: He also noted that there are no seizures that evoke intellectual content, and I’ve seen the same thing. There are no forms of epilepsy where people have calculus seizures, or have logic seizures, or philosophy seizures. Seizures always evoke [00:51:00] either perceptions, movements, emotions, or memories. And Penfield asked, why is there an entire class of mental content that is never evoked by seizures, and can never be evoked by direct stimulation, and that is abstract thought? There’s much more to this, but that’s a place to start.

Arjuna [host]: David, you going to reply to that one?

David Papineau: Sorry, that’s your evidence? That’s your evidence for dualism?

Michael Egnor: [00:51:30] It’s one of them. Yeah, sure.

David Papineau: So Penfield put electrodes at specific places in the brain and stimulated them…

Michael Egnor: I do it too, and he’s right … You can’t evoke intellectual content. My question is why not?

David Papineau: Well, because intellectual content isn’t located at specific places in the brain. It’s distributed all over the brain. What do you expect?

Michael Egnor: Seizures are distributed all over the brain. Why don’t they evoke intellectual… Why [00:52:00] isn’t there a single case report in medical history? No, David, why isn’t there a single case report in medical history of a seizure that evokes intellectual content? A single one, David? …

David Papineau: I’m no neuroscientist, but I can think up the obvious explanation immediately, which is that intellectual thoughts involve complex structures in the brain, and epileptic seizures are incompatible with the presence of those [00:52:30] organized, complex structures. That’s an obvious explanation.

Michael Egnor: But that’s not true, David. That’s not true at all. … There are seizures that evoke complex memories, complex emotions. There are seizures that will make you walk around.

People have driven cars as a part of seizures. But there are mental states that are exceptionally simple. I can believe that one plus one is two. It’s a very simple mental state, and never, never in human history, has there been a report of a seizure [00:53:00] that has done that.

David Papineau: Well, I mean, look, if that’s true… It’s slightly surprising to me, but if that’s true, you’ve just demonstrated that thoughts like one plus one equals two are not simple mental states. They … Let me get your view straight. Which are the things that you can do under [00:54:00] seizure?

Michael Egnor: There are four things that seizures can evoke, generically speaking. David, let me tell you them. They can evoke perceptions, which are fairly simple. They can evoke motor movement, which can be complex… They call them complex partial seizures. They can evoke emotions, and they can evoke memories. And the memories can be very complex. You could have a memory [00:54:30] of your mother in the kitchen when you were eight years old… David, why hasn’t there ever been a seizure where the person, uncontrollably, thinks one plus one equals two? Never been reported in medical history?

David Papineau: Sorry, why has nobody ever sung My Way when they were having an epileptic seizure?

Michael Egnor: Right, people don’t sing songs either. That’s quite true. … What Penfield said, and what I’m saying, is that there’s an entire class of mental states that cannot be evoked physically. That stands as an argument against materialism. Penfield started out as a materialist. He ended his career as a passionate dualist, as I have also, because I’ve seen the same evidence.

David Papineau: Okay, that’s fine. That’s fine. If that’s your reason for being a dualist, [00:56:00] good luck to you. I’m sorry, I mean, I’m an intelligent person who is quite well known for changing their mind when they’re given a good countering argument, but I’m afraid that doesn’t make me feel I ought to be a dualist.

Arjuna [host]: So we’ve got another five minutes. I’m not sure if that’s time to start with another argument from neuroscience or not.

Michael Egnor: Well, I can do that. There’s wonderful work done by Adrian Owen, [00:56:30] who is a cognitive psychologist at Cambridge, in England, working at persistent vegetative state. Persistent vegetative state is a state where the brain is so massively damaged that the assumption has been…

Note: Adrian Owen is best known for discovering that people in persistent vegetative states (PVS), where they cannot move or respond, can have active mental lives.

David Papineau: I mean, this is going to be more of the same. I’m still curious about what Michael thinks about the way that intelligent thought can influence the movements of my muscles. That’s the bit I don’t get.

Note: A number of recent news items have addressed this question as a result of treatments for disabilities. For example, Paralyzed man writes, using only imagination and an algorithm. With implanted electrodes, the volunteer, 65, achieved 90 characters per minute. Also: Prosthetic hand controlled by thoughts alone? It’s here

and

High tech can help the blind see and amputees feel. It’s not a miracle; the human nervous system can work with electronic information.

No one knows how thoughts are generated but there is no question that they can control not only the body but also prostheses that can be attached through the nervous system.

There may be a followup debate. Stay tuned.

You may also wish to read the earlier portions of the debate:

Neurosurgeon Michael Egnor takes on philosopher David Papineau Round 1. In the debate, Egnor begins by offering three fundamental reasons why the mind is not the brain. Neuroscience caused Egnor to honestly doubt Papineau’s materialist perspective that the mind is simply what the brain does.

Round 2: Philosopher Papineau replies to neurosurgeon Egnor. Dr. Papineau is considered to be one of the best defenders of naturalism (nature is all there is), often called “materialism.” Papineau: Mental processes, including conscious processes, are one in the same as physical processes. I’m curious about how Michael Egnor would answer it.

Round 3: Egnor vs Papineau: The Big Bang has no natural beginning. In the debate between theistic neurosurgeon Michael Egnor and naturalist philosopher David Papineau, the question gets round to the origin of the universe itself. Egnor maintains that the Big Bang, which is held to have created the universe, is an effect with no physical cause. Papineau agrees.

Round 4: Egnor vs. Papineau Egnor defends the mind vs. the brain Philosopher David Papineau does not feel that neurosurgeon Michael Egnor is being “entirely helpful” at this point… It became quite the dustup actually. Egnor deals with the brain as an organ, not a theory, and doesn’t see it as equivalent to the mind. Papineau differs.

Round 5: Can traditional philosophy help us understand mind vs. brain? Michael Egnor asks us to look back to the traditional idea that the soul is the “form” of the body. In the Western world, the traditional view of the soul originated with Greek philosophers, chiefly Aristotle and Plato.

Round 6: Quantum physics: Is everything determined? Egnor vs. Papineau Physicalist philosopher David Papineau is clearly unhappy with the implications of quantum mechanics, as neurosurgeon Michael Egnor sets them out. As a physicalist, Papineau is quite sure that the universe is deterministic and he endorses the many-worlds (multiverse) theory.

Also: Philosopher: Consciousness Is Not a Problem. Dualism Is! He says that consciousness is just “brain processes that feel like something” Physicalist David Papineau argues that consciousness “seems mysterious not because of any hidden essence, but only because we think about it in a special way.” In short, it’s all in our heads. But wait, say others, the hard problem of consciousness is not so easily dismissed.