July 1, 2017

TOO LATE TO SAVE TERRI SCHIAVO:

A MAP OF THE SOUL (Michael Egnor, 6 . 29 . 17, First Things)

I'm a neuroscientist and professor of neurosurgery. The mind-brain question haunts me. Neurosurgeons alter the brain on a daily basis, and what we find doesn't fit the prevailing view that the brain runs the mind as computer hardware runs software.

I have scores of patients who are missing large areas of their brains, yet who have quite good minds. I have a patient born with two-thirds of her brain absent. She's a normal junior high kid who loves to play soccer. Another patient, missing a similar amount of brain tissue, is an accomplished musician with a master's degree in English.

How can this be? It wasn't until I read Thomas Aquinas that I began to understand.

Aquinas began by reaching back to an earlier thinker. Following Aristotle, he posited that the human soul has three kinds of powers. It has vegetative powers, which serve physiological functions such as heartbeat, respiration, and metabolism. It has sensitive powers, such as sensation, perception, memory, sensitive appetite, and locomotion. The vegetative and sensitive powers are caused by matter, in a purely physical way.

But the human soul also has intellect and will, powers of a wholly different kind. With our intellect, we can think of universal concepts, such as mercy and justice and abstract mathematics. With our will, we can act on abstract principles. Because thinking of abstract concepts entails thoughts removed from particular things, Aquinas reasoned, intellect couldn't be a material thing. Intellect and will are immaterial powers.

Aquinas taught that our soul's immaterial powers are only facilitated by matter, not caused by it, and the correlation is loose. His insight presaged certain findings of modern neuroscience.

Wilder Penfield, an early-twentieth-century neurosurgeon who pioneered seizure surgery, noted that during brain stimulation on awake patients, he was never able to stimulate the mind itself--the sense of "I"--but only fragmented sensations and perceptions and movements and memories. Our core identity cannot be evoked or altered by physical stimulation of the brain.

Relatedly, Penfield observed that spontaneous electrical discharges in the brain cause involuntary sensations and movements and even emotions, but never abstract reasoning or calculation. There are no "calculus" seizures or "moral" seizures, in which patients involuntarily take second derivatives or ponder mercy.

Similar observations emerge from Roger Sperry's famous studies of patients who had undergone surgery to disconnect the hemispheres of the brain. This was done to prevent seizures. The post-operative patients experienced peculiar perceptual and behavioral changes, but they retained unity of personal identity--a unified intellect and will. The changes Sperry discovered in his research (for which he won a Nobel Prize) were so subtle as to pass unnoticed in everyday life.

In the past decade, British researcher Adrian Owen has found using fMRI imaging that some patients with such severe brain damage that they are considered to be in a persistent vegetative state are actually capable of sophisticated thought. The "comatose" patients' brain scans show that, in reply to questions by an examiner, the patients are in fact thinking and imagining.

Posted by at July 1, 2017 6:16 AM

  

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