It would appear that the western black rhino has bitten the dust.  Not a western black rhino, but the western black rhino.  There’s no more of them.

It’s sometimes hard to say exactly what causes an extinction – something like predation might be the effective cause, but if the population of a species is not under pressure from other directions, it might not in itself be enough: over-predation of a prey species causes a population crash in the predator, which allows the prey to recover, which allows the predator to recover, and so on.  For this reason, it’d be hard to say with absolute certainty that this species has been extinguished because of human activity.  All the same, whatever humanity’s precise role in the extiction of this rhino, it’s overwhelmingly likely that human activity has contributed in some significant way; and it’s highly likely that one of the main factors is the continuing demand for rhino horn as an ingredient in medicine.  (That’s certainly what PZ Myers infers, and it’s hard to deny the plausibility of the idea.)

What comes next is straightforward enough: a lament that this species of rhino has vanished, and all rhinos (and goodness knows what else as well) might go the same way, for the sake of supplying medicines that don’t work.  And it’s true that the sacrifice of a species on the altar of useless folk-remedies is a particular waste.  Not only have we lost something magnificent: we’ve lost it for absolutley no good reason at all.

But let’s imagine for a moment that rhino horn actually did have some medicinal property.  Would that mitigate the loss?  Let’s imagine, in fact, that the property is non-trivial: it’s in the league of being the cure for cancer, rather than the cure for athlete’s foot; and – for the sake of the argument – we’ll allow that whatever chemical it is in the horn that gives it this property is very hard to synthesise – meaning that we can only get it by hunting rhino.  (I know I’m stretching credulity here, but bear with me.)  So: in this situation, some great good relies on hunting rhino.  And perhaps those rhino will be hunted to extinction: call the say on which the last rhino dies “E-Day”.  That’d mean that whatever good we got from rhino horn would no longer be available after E-Day.  But we’d have it up until then, and it is a great good.

So the question is this: would it be permissible to hunt a species to extinction for the sake of providing a drug that will generate vast benefit to another – in this case, ours?

There’s a number of factors that might come into play here.  One is to do with the moral value of species qua species.  If we think that a species has a moral value beyond the aggregate of its members, then there might be something wrong with extinguishing it.  But, of course, the good that’d accrue to humans would have to be balanced against it.  Where we’d put the pivot on that scale is unclear; it might be that we have to sacrifice the rhino, or it might be that we have to sacrifice the good obtained.

On the other hand, we might deny that a species has any value beyond the value of the aggregate of its members.  On this basis, if it’s wrong to cause a member of a species to die, there would be no extra wrong involved in killing the last member of that species.  I’m more inclined to this view.  I think it’s compatible with this to think that we have reasons to care about species in abstracto, but that this is either an aesthetic reason, or something a bit more Kantian, to do with the idea that we don’t get duties based on the rights of a species so much as that we can talk about rights or quasi-rights as the footprint of duties that we hold, perhaps to ourselves.  Extinguishing a species, or destroying some other part of brute nature, for no reason might be, on this account, criticisable because it shows a tendency to arbitrary action.  We’d have to be able to show that there’s a vice to arbitrary action, but that looks doable.

But in my example, the destruction wouldn’t be arbitrary.  It’s conceivable that providing extra good for humanity might turn out to be a defensible thing to do.

One other thing that we ought to question, though, is how much of an obligation there is to provide that extra good for humanity.  If there is an obligation, then it might follow that, however unpleasant it is, we ought to hunt – to extinction, if that’s how things shake out.  At the very least, we’d have more of a defence.

But is there such a duty – in essence, a duty of beneficence?  I’m not sure.  I think that there’s a fairly straightforward duty not to cause harm; but to fail to provide benefit is not the same as to cause harm.  By not acting beneficently, we don’t make anyone worse off than he otherwise would be – we just fail to make him better off.  That doesn’t strike me as blameable.

The point is that beneficence often comes at a price; and so we always have to think about whether a particular instance of beneficence is worth it.  The (slightly strined) example in which benefiting humans means extinguishing another species might provide us with an example of a situation in which it’s not worth it.  (Extinguishing smallpox might be slightly different, inasmuch as that’s a species that is a direct threat in a way that rhinos aren’t.)

I’m at risk of going on for far too long here (you’ve missed that, haven’t you?) – the point I want to raise is that, if we’re concerned about the loss of a species like the rhino, the fact that it might have been lost in the name of ineffective medicine might make the loss worse, but it might not.  And if your inclination is to bemoan the fact that the loss of the western black rhino is attributable to a desire for ineffective pseudomedicines, that does at least imply that you’d be less upset if the treatments were effective.

And I’m not sure that that’s a defensible line to adopt.  It might be, but there’s a lot more argument that’d be required.