Recently, neurosurgeon Michael Egnor received a letter from someone who had watched the video released in May, “Is The Soul Real?”

The viewer was puzzled by Dr. Egnor’s view that abstract thinking can function independently of the brain. What about people who develop dementia and, as a result, can’t reason or think abstractly? Doesn’t their plight show that abstract reasoning cannot really be independent of the brain?

Here’s the video that sparked the reader’s question. Dr. Egnor’s response is below:

Thanks for your question. The material processes of the brain (motor, sensory, memory and emotion) and the immaterial powers of the soul generally work together.

Think about learning calculus. You use your vision, muscles (to write equations) memory and emotion (to be motivated) as well as your capacity for abstract reason. If your vision, memory etc. don’t work well, your abstract powers will be weakened as well. You will have a lot of trouble doing calculus if you are blind, paralyzed, can’t remember anything, and bored.

People with Alzheimer’s have severe memory issues, along with motor, perception and emotional disabilities, and that curtails their powers of reason. – Michael Egnor

The two parts of the human mind

To picture the idea, think of the human mind as having two distinct parts that work together. One part (material processes) is what the brain does. That part comprises movement and senses, memory and emotion. All these powers are activities of the brain and they are directly affected by whatever happens to the brain. A blow to the head, a bit too much to drink, or a dementing illness can, predictably, greatly reduce or destroy their efficiency.

The powers of abstract reasoning and moral choice are elements of the human mind (soul) that do not simply arise from the brain. But to work in this world, they need the brain. That’s why human consciousness is such a conundrum for many researchers. They are trying to locate an immaterial reality in a material reality.

It’s a bit like trying to find justice in the Supreme Court building. Justice exists and it might be found in those halls. But it is not in any specific location there because immaterial realities do not depend on a specific location.

Our immaterial powers need our material powers — and yet…

The immaterial powers of our minds generally depend on the material powers of the brain for their action in the world, as Dr. Egnor notes. People who begin to suffer from dementia lose the sensory awareness and memory needed to make decisions. They often lose the motor ability to carry them out as well. They can be afflicted by inappropriate emotions too. So their immaterial powers are not very effective. Observers may even wonder if they still exist.

But the remarkable thing is that the immaterial powers sometimes come surging back despite the improbable circumstances. Two concepts that Dr. Egnor and I discuss in The Immortal Mind: (Worthy, June 3, 2025) are paradoxical lucidity and terminal lucidity.

Paradoxical lucidity

People who are coping with dementia sometimes suddenly become lucid, for reasons that are not currently known. Dr. Stephen Post, Director, Center for Medical Humanities, Compassionate Care and Bioethics at Stony Brook University, is the author of Dignity for Deeply Forgetful People. In a podcast with Dr. Egnor last year, he noted.

Michael Egnor: When you refer to paradoxical lucidity, what do you mean by that?

Stephen Post: Well, I’m talking about the roughly 80% of caregivers who self-report moments of absolutely surprising lucidity. They assumed that their loved one was gone absent a husk, a shell, incapable of being present in any significant sense. And yet lo and behold, that individual either is totally spontaneously or sometimes prompted by symbols, by personalized music, will actually come back into themselves.

Music is the most effective in this area. There’s a national movement called Music and Memory, and one of our medical students and myself, Angela Lo, did a study of personalized music using an iPod here at the VA nursing home on campus. And we were in a unit where there were probably 30 individuals. They were all sitting in chairs. None of them were speaking, they were ambulatory to some degree. We took them into the activities room.

These were all, of course, veterans and the big television on the wall with the furling flag in the wind, the music was “God Bless America.” I will tell you that 80% of these people actually stood up and sang a few lines, if not a whole verse, if not the whole song of “God Bless America.” And when they did that, they became somatically active. They were affectively present, they were capable of expressing all kinds of emotion that wasn’t that sort of distant flat look that you generally associate with deeply forgetful people. They were more there than not there.

Dr. Post has coined a word for this: rementia, as opposed to dementia — starting to remember again. One key question is, how to develop treatments that make it more common?

And terminal lucidity?

That’s when confused people suddenly become lucid shortly before dying.

If the mind were wholly dependent on the brain, it does not seem likely that these episodes of sudden lucidity would be happening at all — let alone as frequently as they do. There is still much to learn and there are many mysteries; we should approach them with an open mind.