By Andy Ho
SO LET us say you are contemplating pulling the plug on a loved one diagnosed with brain death. Such a patient appears to be unaware of his surroundings. It is assumed he cannot be aware of himself as himself. That is, he has lost his personhood. Doctors tell his next-of-kin: 'Mr Tan is no longer here. This is just his body, a shell. Mr Tan is gone.'
Clinical tests would establish that diagnosis robustly. But the diagnosis of brain death is quite different from the traditional notion of biological death that supervenes some time after the heart stops.
Brain death was a diagnosis first suggested in 1968 by a Harvard Ad Hoc Committee set up with the explicit aim of freeing up beds in intensive care units. Too many people in deep comas were occupying the beds for too long. According to the new idea, such patients were brain dead.
But even if brain death leads inevitably to biological death, the patient remains warm. He bleeds, urinates and defaecates. Live babies have been born to brain dead mothers.
The other organs and even small portions of the brain continue to remain alive, albeit with the aid of ventilators and nursing. So is it just a living corpse?
Unsurprisngly, the new idea caused much confusion. Hence, a Presidential Commission was established to nail down public policy on death. Eventually, the United States Congress passed the Uniform Determination of Death Act, which put the force of law behind the new idea.
However, the Commission said explicitly that it was not 'making a determination of... the death of cells, tissues and organs' but 'the social meaning of death' and 'the status of the human being' in brain death. The person is no longer here; his body has outlived his person.
This assumes that in brain death, one's subjectivity is gone for good. All that remains is a live cadaver. Yet brain death would mean the loss of personhood only if the mind and thus the person and the self are unequivically located in the brain only. This, however, needs to be proven.
Most of us understand intuitively that a person is someone with subjectivity. But most of us are unaware that no one knows how such consciousness arises from the brain and/or whatever other body parts may be involved in self-awareness. This is a problem which exercises philosophers and physicists, but not physicians, unfortunately.
Albert Einstein felt there were two theories. Brain death and the clinical tests that 'prove' it would comprise what he called 'constructive theory', something that just describes a phenomenon without really explaining it.
Quantum mechanics, however, was what Einstein called a 'principled theory', one that begins with principles that explain phenomena. Today, quantum physicists are trying to explain how one's consciousness of oneself can arise out of the same brute matter that makes trees trees and us us.
In Newtonian mechanics, matter was construed as being made up of progressively smaller pellets - molecules, atoms and then subatomic particles. In quantum mechanics, however, matter consists not of tiny pellets but probability waves. It is not just that the structure of matter is representable only in abstract mathematical terms. In fact, physical reality itself is ineffably abstract and mysterious.
How do the roll-of-the-dice probabilistic processes at the quantum level add up to become the definitive physical substrate that gives rise to our consciousness? No one knows. Some have suggested the idea of subsidiary form.
This is something that exists and acts as a unity but can do so only dependently. Thus the brain exists and acts as a unity, but can do so only within a human body. The higher entity, the body, is said to sublate the subsidiary one, the brain.
All entities are made up of subsidiary entities but the former cannot be explained by just summing up the latter. A sentient being like a chimpanzee, or a rational human, cannot be accounted for completely by just summing up their parts. While a neuron is just one big cell, the 50billion inside our skulls add up to a brain. And the brain must join up with other organs and, together, all must be sublated by the body to give rise to life, consciousness, feelings, emotions and self-awareness.
If the brain needs the whole body, in what sense is it the sole seat of the mind? To the Chinese, the 'xin' and to the Japanese, the 'kokoro' located somewhere in the centre of the chest is the seat of the emotions. To Malays, it is the liver.
Who knows? But if no one really knows how consciousness and self-awareness arise from our whole bodies, we cannot be sure that brain death is death of the self and the loss of personhood. For this reason, I believe we should think twice before pulling that plug.
[Comment: I admire Dr Ho's articles for the intelligent arguments and precise attention to empirical and scientific evidence. However in this article, it appears to me that all he offers are some vague doubts. True, we use "mind" and "brain" to mean different things, but there are no evidence other than cultural references (Chinese, Japanese & Malay) to suggest "heart" and "soul" exists or are seated in any other organs, whereas brain damage have changed personalities. I respect Dr Ho for his intelligence and the opinions that emerges from the percolation of data within his mind, but on this matter, I fear his opinion is coloured more by his personal conviction than by the scientific evidence.]