Know the enemy -- the mechanism of death

A couple of weeks ago I linked to this article about British doctor Sam Parnia, who specializes in resuscitation of patients thought to be hours beyond the point of death.  Yesterday a reader sent me this one, which explores the phenomenon further.

What we're really seeing here is that our whole long-established concept of what death is, is mistaken.

We think of death as a sudden shift from one state to a qualitatively different state, which happens at a precise instant, the exact time of which is specifiable in principle, even if it's sometimes hard to pin down in practice.  Furthermore, death is irreversible -- that is, once death occurs, a person cannot be restored to the living state, short of a miracle (literally so, since one of the miracles attributed to Jesus in the Bible is returning a dead person to life).  If a person is said to be dead and later returns to life, it means we were mistaken and the person was not "really" dead in the first place.

All of this is wrong.  It doesn't accurately describe what really happens.

In most cases, death seems to be more analogous to what happens to a machine as it stops running after the failure of some critical part.  The heart or lungs or some other critical organ stop working, due to injury, or loss of energy (due, for example, to massive blood loss from an injury elsewhere), or exhaustion from the gradual decay of aging, or for some other reason.  Other processes which depend on the failed organ begin to slow down and stop; cells and systems which depend on those processes stop functioning.  Decay sets in, in the form of bacteria which start to consume cell components once the immune system stops keeping them in check, and chemical reactions which are no longer constrained to proceed in the ways normal cellular operations require.  At some point fairly early in the process, brain function is sufficiently disrupted that it can no longer sustain consciousness -- and in any case, traumatic injury often shocks the brain into unconsciousness anyway.  Eventually, so much damage has accumulated in the cells that there is no possibility of normal function being restored.

The point is, this is a fairly protracted process.  There is no sudden moment one can point to which constitutes the border between "being alive" and "being dead".  As so often is the case in nature, what seems to us to be an absolute distinction is in fact marked by a gradual transition.  We tend to think that "the moment of death" is the point where the process becomes irreversible -- but as the linked articles show, this point varies depending on the type of technology available.  As our knowledge and machines become more sophisticated, we can restore life in cases which, a few decades ago, would have been judged past the point of no return.  There is also the question of how much "life" can be restored.  Bodies can often be kept mechanically functioning even after brain damage is so severe that consciousness cannot be restored.  Such a person is "alive" in some senses, "not alive" in others.

(People used to define death as the moment the "soul" leaves the body, but this was simply another primitive misunderstanding.  Your consciousness, or "self," or whatever term you prefer to use for it, is not a "thing" distinct from the body, it's a set of processes which your brain is constantly running.  Like programs running on a computer which is suddenly unplugged or damaged so it stops working, these processes don't "go" anywhere when your brain stops working -- they just stop.  Whether they can be set going again, and how well, depends on whether brain function can be restored and how much deterioration has happened in the meantime.)

This raises the hope that the more advanced our medical technology becomes, the later after apparent "death" it will still be possible to restore life.  If we can develop the capabilities in nanorobotics that some futurists expect, it may even be possible to reverse a fairly advanced state of decay by re-arranging the atoms of decay by-products back into the organic compounds from which they came, molecule by molecule, cell by cell -- of course, such technology could prevent most forms of death from happening in the first place.

In any event, the more we know about what death is and how it happens, the better.  Death is the ultimate enemy of humans (hence the post title), and the better we know the enemy, the more victories we can win against him, and the closer we come to achieving his total defeat.