Redefining Reality - The Intellectual Implications of Modern Science

But the idea of using the body’s potential to maintain or regain
its functionality as a condition of personhood becomes even
more complicated when we consider life-support technology.
Are those who are on life-support machines still human in the
full sense of the word?
For many people, death is not bodily death, which can be forestalled
by the use of life-support mechanisms, but brain death.
This view is clearly related to the classical metaphysical picture
of dualism, in which people are made up of two different
things: material bodies and immaterial souls.
In the dualistic view, when someone is brain dead, the body is
still present, but the spirit or mind is gone. The idea that brain
death is human death is tied to this dualistic view of the body,
which has largely been abandoned in science.
Even if we think of the mind as emerging from the brain, the
mind plays a crucial role in being human. The mind is what lets
us plan and what gives us autonomy. When someone is brain
dead, there is not a self to project itself into the future.
Of course, the brain science we have looked at makes this
problematic, too, because, as we have seen, the brain often acts on
the action. If the brain is not the seat of autonomy, why should we
believe that brain death removes personhood? Perhaps in the future,
we will be able to resuscitate the brain in the same way that we
can resuscitate the heart. This is the thinking behind cryonics, the
preservation of one’s body or head after death by freezing.
Humans are made up of cells, and we have a natural life cycle of
birth, growth, aging, and death. This happens for the body as a whole
because it also happens for cells individually. With few exceptions,
our cells replenish themselves in the body by dividing, but this
process does not create two exact copies of the parent cell.
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