You can never watch Blade Runner too many times, and I’m due for another viewing. In D. E. Wittkower’s anthology Philip K. Dick and Philosophy, there’s an article by Ross Barham which makes some remarks about the movie’s famous “replicants” and their relationship to human beings which are interesting though, in my view, mistaken. Barham considers how we might understand the two kinds of creature in light of Aristotle’s four causes, and suggests that this is easier to do with replicants than with human beings. This is, I think, the reverse of the truth. But Barham’s reasons are not hard to understand given modern assumptions (which Aristotle would reject) about nature in general and human nature in particular.
Barham suggests that, where replicants are concerned, a four-cause analysis would look something like this: their efficient cause is the Tyrell Corporation and its engineers; their material cause is to be found in the biological and mechanical constituents out of which they are constructed; their formal cause is the human-like pattern on which the Tyrell Corporation designed them; and their final cause is to function as human-like slave laborers.
With human beings, Barham says, things are different. Here, he thinks, the analysis looks like this: their efficient cause is, proximately, their parents, and remotely, evolution; their material cause is the biochemical matter out of which they are constituted; and their formal cause is the “blueprint” to be found in their DNA. But with human beings, Barham says, it’s not so clear what their final cause is.
Now, you might think that his reason for saying this has something to do with attributing our remote origin to evolution rather than divine creation. You might think, in other words, that he is supposing that if God didn’t make us, then we must not have a purpose or final cause. But that is not Barham’s reason -- and it’s a good thing, since that would not be a good reason for saying it. For Aristotelians, at least where true substances are concerned -- water, lead, gold, copper, trees, birds, spiders, human beings, etc. -- you don’t need to know anything about their remote origins in order to know their teleological features or final causes, any more than you need to know their remote origins in order to know their formal or material or (immediate) efficient causes.
For example, you don’t need to know whether God made acorns in order to know that they are “directed at” or “point toward” becoming oaks. You don’t need to know whether God made trees in order to know that their roots are “for” taking in water and nutrients and giving the tree stability. You don’t need to know whether God made spiders in order to know that their webs have the function of allowing them to catch prey. You don’t need to know whether God made copper in order to know that copper has a tendency to conduct electricity. Etc. All you need to do is to observe how birds and spiders tend to act when in their mature and healthy state, what acorns and copper tend to do under various circumstances, etc. The causal powers a thing exhibits are the key to understanding its finality or “directedness.” (Recall that, contrary to the standard caricature, most finality or teleology in nature involves nothing as fancy as biological function. It typically involves just a mere “directedness” or “pointing” toward a certain standard outcome or range of outcomes.)
Barham is aware that for Aristotle, to know a natural object’s teleological features, one needs to observe how it characteristically behaves, and that this is as true of human beings as it is of anything else. He is also aware that for Aristotle, what is characteristic of human beings is that they exhibit rational powers, so that living in accordance with reason is, for Aristotle, our final cause.
So far so good. But now comes Barham’s mistake. He thinks Aristotle’s answer faces the following difficulties. First, Barham thinks that there are alterative candidates for our final cause or natural end that are no less plausible than rationality. His examples are agency, the capacity for morality, and love. Second, he notes that we often act irrationally and suggests that replicants can be no less rational than human beings are -- in which case rationality is neither necessary nor sufficient for being a human being. Third, he seems to think that a problem with any proposed characteristic (rationality, moral behavior, love, or whatever) is that there are instances of human beings who don’t exhibit it -- so that (Barham seems to conclude) none of them can be the final cause of human beings as such. (In fairness to Barham, in some cases it’s not clear whether these are objections Barham himself endorses, or merely objections he thinks are implicit in Blade Runner.)
Longtime readers no doubt know already how I would respond to objections of this sort. (They will also be familiar with the Aristotelian and Scholastic notions to be deployed below -- notions I’ve spelled out and defended in many places, and most systematically in Scholastic Metaphysics.)
First, that we often act irrationally does not entail that we are not rational. Indeed, you cannot act irrationally unless you are rational, in the relevant sense of “rational.” To be irrational is not the same thing as to be non-rational. Rather, to be irrational is to reason badly, or to let one’s emotion cloud one’s reason, or to be impaired somehow (by mental illness or brain damage, say) so that one is prevented from exercising one’s reason -- all of which presupposes that one does indeed havereason. Contrast a spider, say, which is not irrational precisely because it does not even rise to the level of reasoning badly. A spider is instead non-rational.
Second, agency, morality, and love are not really in competition with rationality as candidates for our characteristic activity, certainly not on the analysis an Aristotelian like Aquinas would put forward. For these are all themselves just special cases of rationality. Consider Aquinas’s view that will follows upon intellect. Will is “rational appetite,” the tendency to be drawn toward what the intellect sees to be good. To be “rational,” then, is for Aquinas to have a will as well as an intellect. Now, agency, in the sense here in question, is just the capacity to behave in light of reason -- that is to say, to have a will. Morality is just a matter of an agent’s pursuing what the intellect perceives to be good for him and avoiding what it perceives to be bad. Loving a thing is just willing what is good for it. So, the Aristotelian can take Barham’s alleged alternatives not to be true alternatives to rationality at all, but indeed to be instances of rationality.
Third, that some human being doesn’t actually exhibit one of the features in question -- for example, that there are sociopaths unmoved by moral considerations, or that severely brain damaged people cannot exercise reason -- doesn’t entail that these features are not part of the nature of all human beings after all. To appeal to one of my stock examples, dogs are of their nature four-legged, even if there are occasional dogs which, due to injury or genetic defect, are missing a leg. For to say that dogs are of their nature four-legged does not mean, on an Aristotelian understanding of the nature or essence of a thing, that every single dog will in fact have four-legs. It means that any dog in its mature and undamaged state will have four legs. Even three-legged dogs by nature have four legs -- that is to say, being four-legged is what they naturally tend toward. It’s just that in a three-legged dog this tendency has been frustrated.
Similarly, a human being who is so severely brain damaged that he can no longer reason, or so psychologically aberrant that he is utterly unmoved by the demands of morality, is still someone who by nature tends toward rational activity and a sense of guilt at doing evil. It’s just that, as with the damaged dog, the manifestation of the natural tendencies has been blocked. (Note that this does not make them any less human, any more than a three-legged dog is any less a dog. An imperfect or damaged dog is in no way a non-dog, and an imperfect or damaged human being is in no way non-human. You have actually to be an X in the first place in order to count as an imperfect or damaged X.)
What about the suggestion that Blade Runner’s replicants, like humans, have rationality? Here things are a little more complicated, but only because replicants are, of course, fictional. There is no “fact of the matter” about what a replicant is; hence it’s not entirely clear what to say about them. What we are told about them makes the situation highly ambiguous. On the one hand, superficially they seem to be like robots or androids. And in that case I would say that they are metaphysically on all fours with computers, clocks, toaster ovens, etc. That is to say, they have mere accidental forms rather than substantial forms, and are thus not true substances. On the other hand, on closer consideration they are far more human-like than the stereotypical android or robot is. Not only are they at least partially made out of biological material, but they are so close to human beings in their appearance that it seems that a physical inspection (including an X-ray or the like) wouldn’t reveal something to be a replicant. Hence Rick Deckard (Harrison Ford) has to administer a complex psychological test to determine whether Rachael (Sean Young) is a replicant. But then replicants seem to have an organic unity that indicates that they have substantial forms rather than merely accidental forms, and thus are true substances. (I have discussed the difference between substantial and accidental form in many places, such as here, here, and here. For the full story, see chapter 3 of Scholastic Metaphysics.)
Now, either way we interpret them, replicants will not be true counterexamples to the Aristotelian claim that what is distinctive about human beings is that they are rational animals. For suppose that replicants have only accidental forms, and thus are not true substances. They are in this case merely mechanical systems, like computers running software or clocks which have been designed to display the time. And in that case, for reasons I’ve stated many times (e.g., recently, here) they would from the Aristotelian point of view no more literally have rationality than a statue of a man literally has eyes. They would merely behave as if they had it. The rationality would all be observer-relative -- a projection of the human programmers of the replicant’s imitation brain, rather than something really in the replicant itself.
Suppose instead, though, that replicants have substantial forms and thus are true substances. Then it is much more plausible to say that they have genuine rationality, as well as true sensation, appetite, locomotion, and the other functions we share with non-human animals. But in that case they would be rational animals -- in which case they would be human beings. True, they would be human beings with very exotic origins, but that is a question of where they came from, and that is a different question from the question of what they are. On this scenario, they would be more like clones of human beings (even if not exactly like clones) than they would be like robots or androids, and clones of human beings would certainly be human beings. But if replicants are just exotic human beings, then, once again, they are not counterexamples to the claim that being rational is what is distinctive of human beings.
Of course, all of this presupposes the Aristotelian metaphysics of substance, but the point is that, contrary to what Barham implies, that metaphysics has ample resources to deal with the purported counterexamples he thinks Blade Runner is offering us.