RIVERSIDE — Descartes was fond of operating on live animals--dogs and other mammals. They were merely mechanisms, he explained, and although they might exhibit pain behavior, they could not feel pain. It was a classical question of metaphysics: whether animals had souls or were mindless contrivances instead. Descartes said they were beast machines.
Metaphysics outlived Descartes. And in recent years animal vivisection has come to be controversial, as once it was when practiced on human beings: prisoners and those in the minority. Some challenge the use of animals in laboratory research, because they argue animals also have souls and consequently minds sufficiently like our own to conceive of pain and experience it as we do. Others contend that we are mechanisms too and as such should not inflict on others what we wouldn't inflict upon ourselves.
It is this second sort of insistence that is more or less unique to modern humans, now that the difference between human beings and other mammals has become less conspicuous due to comparative neurology and a greater comprehension of biochemistry. With modern knowledge has come increasing uncertainty regarding the existence of a separate immaterial soul housed in flesh and bones, a soul divinely placed there to segregate us from the beasts. Metaphysically speaking, once we regard ourselves as indistinguishable from the other animals, it's all quite natural to question our hegemony over other species. It's a new dilemma that we face, in an era where the soul has lost its original meaning and its independence from the body.
That human beings are just another species is a philosophical hypothesis that matters quite a lot to the animals involved. If persons are mechanisms too, then maybe we should show other living mechanisms the same respect we show ourselves--at least for animals that are like us, such as vertebrates that dream. Such is the inverse of Descartes' dichotomy. Then again, if our relation to the other animals is only that of one animal to another, who is to say that we cannot be perfectly bestial, if need be? Or are we to re-import our superiority, as that of a more intelligent creation to a less-developed one? If that is the case, it seems perfectly reasonable to make use of some such animals, especially the dumber ones, for rational purposes of our own. And here we are back with Descartes again.
It is not particularly rational to conclude that as one animal to another, we must thereby exercise special constraint upon the other species, when they fail to exercise that constraint among themselves. Nor does it make much sense to be paternalistic to lesser creatures in a purely sentimental and capricious way, being kind to kittens and cruel to termites.
The trouble, as I see it, is that we wish to show our solidarity with other animals and at the same time to presume our rational superiority over them. If life were really brutish, then animals would go on eating other animals, using them and even abusing them, if we are all just beast machines. If we are in a special position of authority over other animals, due to a natural or divine superiority, then on what grounds are we to decide to make use of them, except from the viewpoint of our human interests?
We simply do not know if animals have souls, God knows. Nor do we know which mechanisms are sufficiently like humans to be protected by us as we protect ourselves. Nor do we know whether being almost human is the only way to justify giving animals our protection. That's the trouble with metaphysics. There always seem to be more questions than there are answers. Maybe in a century or so we might be able to make informed comparisons between our own neuroanatomy and that of gorillas or of whales, assuming any are alive by then. Only subsequent generations may know whether the slaughter of whales for commercial or even scientific purposes is akin to murder, and whether those groups who have opposed it, such as Greenpeace or the Sea Shepherd Conservation Society, which claimed responsibility for sinking two of Iceland's four whaling vessels last Sunday, are the unsung heroes of our time. In retrospect we might discover man's inhumanity to man's own kin. Yet even if we knew enough today to single out animals like ourselves, there will also always be other considerations to extend our protection to lesser species too, from fish to protozoa. So what are we to do today about tomorrow's knowledge, not to mention tomorrow's arguments about eating lowly chickens or feeding fish to seals?