Why do we die? Is death a punishment or a liberation? Is it something that in some sense should not happen to us, or is it natural? Is the death of a human being entirely of a piece with the death of any living thing and to be explained in the same way? Should we look for a moral explanation of death, or is it better to understand it naturalistically, as something inevitable or understandable, given our composition and structure? It is striking that Platonic answers easily come to mind for such questions, but Aristotle’s position is by no means as obvious. R.A.H. King in Aristotle on Life and Death aims to give us the Aristotelian view on ultimate matters through the methodological device of attending carefully to, in effect, Aristotle’s account of digestion. Some people today think that good nutrition is the key to avoiding death; King’s view is that a good account of nutrition in Aristotle holds the key to confronting what death meant to him.
King’s central idea is that of the life-cycle: every living thing is meant by nature to go through a cycle of growth, activity in its prime, and decay leading to death. The teleological, cosmological explanation of this is that everything aims to imitate the Prime Mover in its eternal felicity insofar as it is able; but no composite, and therefore nothing composed of body and soul, can remain in existence as an individual for ever. Yet composite things can exist without end as a species (‘numerically mortal but generically immortal’), thus individuals in a species of living things are meant to succeed one another in an endless cycle. The efficient causal explanation makes reference to the nutritive soul: a living thing grows, remains in its prime, and decays, depending upon whether its internal heat is increasing, kept at a steady state, or consuming itself on account of a failure in compensatory cooling, which typically occurs as a result of a hardening of the lungs — the lungs being the principle instrument of cooling in an animal.
Because living things can imitate the divine only through the species, and by reproduction, it is good that that they die; thus “it is hardly surprising”, King says, “that there are no texts in which Aristotle says that death is bad” (14). But living things do not die because there is some kind of artificial mechanism which, so to speak, pulls the rug out from under them when their time has expired. There is no internal time clock on Aristotle’s view, according to King, that tells the nutritive soul to initiate decay after an animal in its prime has enjoyed its due measure of life. Rather, “full functioning is possible only through the living being growing in such a way as to reach it, and such a grown body must decay, finally arriving at the failure of all function” (14).
Thus, on the Aristotelian view of decay and death as explained by King, Governor Lamm of Colorado was partially correct and partially mistaken when he once remarked, notoriously, that “the elderly have a duty to die and get out of the way, like fallen leaves”. It was not correct of him to regard death as something that might be imposed artificially, or regarded as an extrinsic requirement, but it was correct for him to liken the elderly (at least as regards their nutritive soul) to withering leaves.
One might quibble as to whether Aristotle never says that death is bad. In the Nicomachean Ethics he says that death is ‘the most fearful thing’, and he also says that fear always has as its object things that are without qualification bad (1115a8, 26). (That he also says that ‘it is thought that a dead man has neither good nor bad’, a27, is beside the point, because the badness of death would consist precisely in someone’s no longer being a subject of weal or woe.) Perhaps this is not a small point: if we were designed by nature to die, then why would we also be designed to fear death as the worst evil? And it’s not merely violent death in battle that people fear. If King’s account were correct, and death were as natural and good as new life and growth, then why wouldn’t we look forward to death as much as we look forward to reproduction? It won’t do to say that death is good for the species only by being bad for the individual, because reproduction, too, is good for the species while being, insofar as it requires sacrifices, bad for the individual; furthermore, as regards reproduction, we are capable of making what is good for others our own good. What these considerations suggest is that, for human beings, one wants a moral as well as a teleological and efficient causal explanation of death. For instance, if human beings are by nature ‘political animals’, then presumably by nature we are meant to regard our death as good only if on behalf of family, friends, and homeland — the species makes no claim on us except through these.
One might wonder, too, about the success of King’s explanation of decay as the necessary result of something’s having grown to reach its prime. Why is it necessary? It’s not clear that this gets explained. Yes, granted that decay must follow growth to maturity, it would be foolish and immature to welcome the latter but grumble at the former: decay would be a kind of price one pays after the fact for having lived at one’s full powers. But why must decay follow? King seems merely to criticize misguided explanations — the internal time-bomb, already mentioned; or the theory that our simply having matter implies that we must decay, since matter (as in the Timaeus) is not fully controllable.
King uses the image of a sand-castle and points out that one does not need to do anything for it to decay, one merely needs to stop repairing it; and similarly, he suggests, decay comes simply from the nutritive soul’s ceasing to do what it had been doing up to its prime, perhaps because once the living thing reaches its prime it has reached its goal and has nothing more to achieve. But the prime is apparently defined in terms of reproduction (“The achievement closest to the nature of a living thing that has reached maturity and is not damaged… is to produce another being like itself”, De Anima 415a27), and we do not see in all animals (although this does happen in some insects) that their dying off is linked to their having successfully reproduced and raised their offspring. And, in any case, why does the nutritive soul cease making the necessary repairs? If it must fail in its powers, then (again) why? We need to be given an account or shown why this question is feckless. “Generation provides a way in which the best end, relatively speaking, can be attained, but the price for this achievement is the other end, death” (15). Why must there be such a price? Why cannot mortal beings imitate the divine by coming into existence and then remaining so? “From the peak, one has to go downhill”(15) — this begs the question.
King wants decay and death to be a matter of the soul’s giving out because it has performed what it was meant to perform, akin to the exhaustion that precedes sleep. As we said, it is not to be attributed to “some mechanism in the living thing, as it were a time-bomb, but in the structure of the being in question, as something that comes to be”(16). But this seems not to give sufficient weight to Aristotle’s language, and it seems furthermore to involve a false contrast. Aristotle repeatedly refers to the nutritive soul as the principle of the decay ( phthisis) of a living thing just as much as of its growth (e.g. De Anima 411a30, 412a15, 413a25); presumably its causality is the same in both cases; but then to say that the soul simply fails in the one case seems incorrect, because something that fails is not in that respect a cause. Again, the alternative between a time-bomb and exhaustion seems a false alternative, because what is objectionable about the time-bomb is that it is extrinsic: nothing in a living thing could work in that way, not simply decay. So what is the objection if we say that the trigger is an internal principle of self-limitation?
Besides King’s stimulating remarks on the life-cycle, the book contains lucid and insightful explanations of fundamental notions in Aristotle’s theory of life (soul, form and matter, nutrition, mixture) as well as accurate explanations of the corresponding physiology. The book bears many of the marks of the dissertation from which it is derived. Some of these are extremely helpful, such as summaries at the beginning and end of chapters, and a welcome methodological explicitness; others are less so in a book for popular consumption and nourishment, such as 40 pages of footnotes, a rather large helping in a book of under 200 pages. For all that, King’s insightful and scholarly discussion is to be welcomed as a valuable contribution to Aristotelian philosophy of biology — and a careful reading of it might just aid in internal cooling and thereby prolong life.