THE TRANSIENCE OF DEATH: Death, as the living understand it, is not antithetical to life but to birth since, like the latter, it is a momentary phenomenon rather than something that extends over a long period of time, the way life usually does. Once a person has died, the phenomenon of death is consummated and the corpse thereupon begins to decompose, leaving, after a number of years, scarcely a trace of its remains. Now where, in consequence of this process of decomposition, there is nothing or next to nothing remaining, the word 'dead' has no real applicability. One cannot refer to a hole in the ground with nothing in it as the hole of a dead person, even if it is still officially a grave by dint of the fact that a corpse was once buried there in some kind of coffin. And so it should be fairly obvious that 'the dead' are really very transient phenomena, nothing to work-up to the status of an antithesis to the living.
Montaigne's life, for example, came to an end in 1592, his corpse doubtless quickly began to decompose, and one would, I guess, be quite justified in believing that by 1610 the former essayist had been reduced to a skeleton, to which one normally applies an 'it' rather than a 'he'. Thus, strictly speaking, one cannot say of Montaigne that 'he has been dead for over four-hundred years' (since the process of death and decay only lasts as long as there is anything approximating to a 'he' discernible), but simply that 'he died in 1592'.
Consequently, as an opposition to life conceived as a period of time during which one is conscious of existing, we have the not-life, i.e. the period before birth and after death which embraces both foetus and corpse. As an opposition to life conceived in terms of that which lives, i.e. the animate, we have the inanimate. And, finally, as an opposition to birth we have - death.