Are Minds a Different Substance from Brains?

Neurosurgeon Michael Egnor recently debated naturalistic philosopher David Papineau on the mind/body problem. Egnor, a Catholic theist, believes that the mind and the body (i.e. the brain) are two distinct substances and that mind cannot be reduced to material stuff like the brain or it's functions.

Papineau is an atheist who believes that mind and brain are essentially the same thing, that what we call mind can be explained in terms of physical laws and processes.

A summary of Round One of the debate in which Egnor goes first can be read at Mind Matters. Egnor begins by explaining how his work in neuroscience is what led him to abandon atheism and become a Catholic in his mid-forties.

He adds that, "I had felt through much of my career that physics, biochemistry, biology, and particularly neuroscience, just didn’t make a lot of sense in a materialist paradigm."

He notes that he,

kept seeing patients who had largely missing brains or had brains split in half (for medical reasons, to treat otherwise intractable epilepsy) who lived normal lives. Whatever the mind is, it did not appear to be wholly dependent on the brain. And I learned a fair amount of neuroscience, but I found that I seemed to know less and less about the mind the more neuroscience I learned.

I’ve been doing neurosurgery now for the better part of 40 years, I’ve done 7,000 brain operations, and I’ve become convinced that there’s much more to the mind than the brain alone explains.

He then gives three reasons why he rejects the idea that the mind cannot be explained just in terms of the brain:

The first is that human mental states are characterized, in many instances, by the capacity for reason, by the ability to make logical inferences, to make logical connections, and a difficulty that materialism faces is that, while all of our logical reasoning entails logical connections between ideas, there are no logical connections between brain states.

Brain states are connected by physical laws, not by laws of logic, and that at least the identity theory brand of materialism, I think fails in this regard, because that is something about the mind, that is the ability to make logical connections, that is not present in the brain. The brain has no logic. The brain just has physics.

In other words, the brain performs electrochemical reactions along neurons, but electrochemical reactions do not employ logic. The provenience of logic is inexplicable in terms of material substance and the laws of physics.

The second reason why I think we can’t explain the mind entirely on the basis of brain states is the existence of qualia, what David Chalmers says is the Hard Problem of consciousness. I can see no reason to infer that any brain state would create first-person experience.

Brain states are third-person ontologies, so I don’t think qualia can be explained in a materialist perspective.

To grasp more firmly what Egnor is getting at imagine that you look at grass and see the color green. Where and what is the sensation of green? It's not in the grass but in your brain, but there's a problem.

The sensation is the product of a chain of chemical reactions that begin in your retina and are converted to an electrical signal transmitted along the optic nerve to your brain, but neither the light from the grass nor the chemical reactions it produces in the retina nor the electrical impulse that goes to the brain are "green."

Nor does the color green appear anywhere in your brain when you see the grass. So where is the green? What are we sensing when we experience the sensation of green? It doesn't seem explicable just in terms of anything in the brain. The same is true for pain, pleasure and all the phenomena of our sense experience.

And the third reason why I don’t think mind states can be explained materialistically is the phenomenon of intentionality.... the hallmark of mental states is that they’re always about something. They’re always pointed at something. There’s a goal to them.

And physical things never have any intrinsic about-ness. They’re simply collections of matter. So the salient characteristic of a mental state is that it’s about something. It has meaning. And you might say the salient character of a physical thing is that it’s never about anything, never has any meaning.

In physical terms the words you're reading are just chemical dots on a screen. They have no meaning in themselves, but they gain meaning when someone sees them. If all that's involved in this are meaningless physical patterns being apprehended by a material nervous system that consists of electrochemical reactions, where does the meaning come from?

This really is a perplexing question. Unfortunately, Papineau's response is to simply assert that there's really no problem here and the subsequent debate gets bogged down, as these kinds of debates often do, on an ancillary question.

Even so, Egnor's opening statement presents a powerful challenge to materialist philosophies of mind. You can watch his entire opening statement as well as the rest of the debate here: