I have portrayed life as replicator-based self-perpetuation, and human beings as (possibly developing) members of the species Homo sapiens. I considered several ways of understanding what we are and the conditions under which we persist before retreating to agnosticism on the matter. In this chapter I discuss death. It seems apparent that a death is the ending of a life, but in several respects the term ‘death’ is unclear and ambiguous. My first task, taken up in the first section, is to clarify it. In the next section I consider criteria by which we can recognize that an individual's death has occurred. It turns out that the criteria that have been adopted in the United States and in the United Kingdom are not accurate, and it is difficult indeed to see what to put in their place.

DEATH CLARIFIED

In order to clarify what death is, I will begin by distinguishing it from aging. Aging is not the same thing as death, but the two phenomena overlap in fascinating ways. Then I will discuss what it is for a life to end: is it, for example, a process a thing can undergo or is it the completion of that process? I will also contrast life's ending with its suspension; if, like a clock's movement, our vital processes are interrupted but may be restarted, have we died? Next I will consider how ceasing to exist is related to dying: may we cease to exist deathlessly, or die without ceasing to exist? The answer is not as obvious as it might seem.