Readers will be familiar with Stony Brook neurosurgeon Michael Egnor’s writings and podcasts. He is also author, along with Denyse O’Leary, of The Immortal Mind (Worthy, June 3, 2025), which he and Sean McDowell discuss here:

Says Sean:

Many scientists and doctors believe that there is no such thing as the soul. Dr. Michael Egnor is a neurosurgeon who presents the case that the brain alone does not explain the mind. Using modern neuroscience and his vast surgical experience, he believes there is a spiritual soul that transcends the brain, using fascinating case studies to prove his claim. Today, he’s here to discuss his new book, which comes out June 3.

Why Dr. Egnor Began to Doubt Physicalism:

Michael Egnor: As a neurosurgeon I began finding patients who had large parts of their brains missing. A good example was a little girl who was born with only about half her brain and I counseled her family that this didn’t look good. I couldn’t be sure how she would do but it didn’t look encouraging. 

And, as she grew up, I followed her and she was normal at every stage of development, in fact, rather bright. She’s now in her mid 20s and a vibrant, normal young woman, has a great job.

Her mother says she’s too smart for for her own good — and she has half a brain. I have a number of other patients with major parts of their brains missing who were really okay or really fine — and that didn’t fit any of the neuroanatomy textbooks that I that I read in medical school

Seven thousand operations and many such experiences later, Dr. Egnor is assembling a case for the reality of the immaterial human mind (or soul).

So What Is the Soul?

The popular idea of the soul, as a sort of “ghost,” dates from the 17th century. It is not, perhaps surprisingly, the traditional philosophical (or Christian) one:

Michael Egnor: We tend to think of souls as “ghosty” things that kind of inhabit our bodies. Like, they’re the same shape as us but they step outside of us and they’re translucent or something. And that that’s not really the classical way of understanding the soul. Thomas Aquinas (1225–1274) believed that the soul was, essentially, everything about you that makes you different from a dead body…

So the fact that I’m talking now is part of my soul because if I were dead, I wouldn’t talk. That I’m breathing is also part of my soul because if I were dead I wouldn’t breathe.

Plants and Animals Are Alive. Do They Have Souls, Too?

Michael Egnor: Plants have souls. Their souls make them grow and reproduce and and take nourishment and things like that. They’re living things.

Animals have souls. The [soul] makes my dog like food and walk around and bark and do dog things.

So How Is the Human Soul Different?

Michael Egnor: Our souls differ from the souls of any other living thing in that our souls are rational souls. That’s the “abstract thought” part that no other living thing has. That kind of soul is a spiritual soul. Therefore our soul is a spirit whereas other living things just have souls that run their bodies — souls that run the plant, souls that run the dog.

A spirit has many characteristics that are quite different. Our spirits have the ability to reason, to act freely, to do free will. Our spiritual souls are immortal… Spirits can’t disintegrate because they don’t have parts; they’re not made of matter.

That spiritual component of the human soul, which is by its nature immaterial and immortal, is what survives when a human body dies.

Readers may wish to quarrel with this understanding of the human soul. But it is only fair to point out that it is the traditional one. The popular “ghost in the machine” approach is much more recent, popularized by 17th-century mathematician René Descartes (1596–1650). When atheists deny the existence of the soul, they usually have this Cartesian idea in mind.

Note: Some readers might share prominent neuroscientist Christof Koch’s vehement dislike of the idea that beloved animals’ souls die with the body and thus they “do not go to heaven.” But there seems to be a misunderstanding here. Traditionally, human souls have been considered immortal by nature — that is, immortal regardless of the outcome for the soul. But the fact that animal souls are not thought to be immortal by nature would not preclude an animal from being recreated, as C. S. Lewis (1898–1963) has pointed out. That is a separate question. See, for example, “Do Any Dogs Go to Heaven? If So, Why?” for more on this point.

Pre-order The Immortal Mind, by Michael Egnor and Denyse O’Leary, and get a sneak peek exclusive excerpt from the book as well as the full digital book anthology Minding the Brain.

Cross-posted at Mind Matters News.