My friend Kleiner has been trying for years to get me to understand what final causes really are supposed to be. When I’ve talked about them in various classes, I’ve always called them the ‘pulling cause’: a final cause pulls the little acorn into becoming an oak, pulls the embryon into becoming a human, etc. I suppose I gained this understanding through studying early modern philosophers, who routinely ridicule the doctrine of final causes as a clear example of using some later state (i.e., adult oak) to explain the behavior of an earlier thing (acorn). That would be backward causation, and silly and stupid and wrong.
But Kleiner has insisted this ‘pulling’ account is all wrong, and now I think I get it. Aristotle never intends to use later states to explain earlier ones — in fact (I am told), he somewhere denies this is even possible. Instead, when Aristotle defines the four causes, he is identifying four ways in which we might try to account for a thing or its behavior. We might point to the stuff it’s made of, or the way its parts are organized, or what caused it to come into existence, or what the point of its behavior is. And the fact is, we do appeal to accounts of the last sort all the time. We ask, “Why is the dog circling before it lays down?” and “Why is the turle coming to shore?” and “Why do cuckoos lay their eggs in other birds’ nests?” and we expect some answer which points to the fruitfulness of this behavior. And when we do this, we don’t mean to commit ourselves to any sort of spooky backward causation. We are just identifying the function/role/purpose of that behavior. In evolutionary terms, when we’re explaining behaviors or features of organisms, we want to know what purpose the behavior or features serve, such that they were at one time selected for rather than against.
OK. Now consider this very interesting passage from Aristotle’s Physics, book 2, part 8:
“A difficulty presents itself: why should not nature work, not for the sake of something, nor because it is better so, but just as the sky rains, not in order to make the corn grow, but of necessity? What is drawn up must cool, and what has been cooled must become water and descend, the result of this being that the corn grows. Similarly if a man’s crop is spoiled on the threshing-floor, the rain did not fall for the sake of this – in order that the crop might be spoiled – but that result just followed. Why then should it not be the same with the parts in nature, e.g. that our teeth should come up of necessity – the front teeth sharp, fitted for tearing, the molars broad and useful for grinding down the food – since they did not arise for this end, but it was merely a coincident result; and so with all other parts in which we suppose that there is purpose? Wherever then all the parts came about just as they would have been if they had come to be for an end, such things survived, being organized spontaneously in a fitting way; whereas those which grew otherwise perished and continue to perish, as Empedocles says his ‘man-faced ox-progeny’ did.
“Such are the arguments (and others of the kind) which may cause difficulty on this point. Yet it is impossible that this should be the true view. For teeth and all other natural things either invariably or normally come about in a given way; but this is not true of the results of chance or spontaneity. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but we do to frequent rain in summer; nor heat in the dog-days, but only when we have it in winter. So if it is agreed generally that things are either the result of coincidence or for an end, and some things cannot be the result of coincidence, then it follows that they must be for an end; and that such things are all due to nature even the champions of the theory which is before us would agree. Therefore action for an end is present in things which come to be and are by nature.”
The view Aristotle describes, and then goes on to dismiss, is evolution through natural selection. EXACTLY. Some lucky folks happen to get sharp teeth up front, and flat ones in the back, and that works out well for them, and they out-eat everyone else, and the others perish, and the good teeth creatures have kids with good teeth, etc. But Aristotle dismisses this idea because, he says, if an event or thing comes about by chance, that simply means that it does not come about regularly. Anything that comes about regularly, he says, must come about for an end. And that means it is not chancy, but end-related.
I can’t figure out what this means. At first, what Aristotle seems to be ignoring is the possibility that something can first come about by chance, and then become regular (and so lose its chanciness). So the teeth come about, and then it proves to be useful, and so those with them outsurvive the others, etc. Or is he saying that the fact that the feature becomes regular itself indicates that there must be some purpose the feature is serving? That makes some sense. After all, it’s no accident that the animals with the usefully-arranged teeth flourish; it’s the fact that the teeth are useful that explains this. So, in this sense, their flourishing is not by chance. But then why is Aristotle saying there is anything wrong with the natural selection model? That seems to be exactly what the model is claiming. So who does he imagine his opponents to be? Maybe he is disputing the claim that a feature can only seem to come about for a purpose without really coming about for that purpose. But then that would mean that it is simply incoherent to say that the good dentition itself came about by chance, but turned out to be useful. I’m trying to see the incoherence about this, but I can’t. Can’t something come about for no end, but persist because of an end? Is the problem that he is taking the claim “that things are either the result of coincidence or for an end” too severely, and not allowing for mixed cases? That seems to be the problem, though I can’t see what would motivate him to propound this “law” so forcefully.