post about my book while I was gone, and asked a good question: in defending degrees of respect, with humans entitled to more, how much do I really diverge from Tom Regan's seminal book The Case for Animal Rights? Though Regan thinks every animal (or rather, every "subject of a life") has the same inherent value, and so has the same prima facie right to be treated with respect, he allows that in certain special situations, we ought to give priority to (normal) humans over (normal) animals. Given that concession, is there really any more than a verbal difference between my view and his?
In fact, I think there's much more than a verbal difference. That becomes clear when you consider the nature of the special situations in which Regan thinks that individual differences (between subjects of a life, human or animal) could make a moral difference. Angus calls them situations of "unavoidable choice," but that suggests you'd be in such a situation much more often than Regan believes.
The override situations Regan discusses are exactly five. Each one is very carefully analyzed to make it clear why it's an override situation. That's not to say he's committed to just 5 override situations and not 6 or 7 or 8, but we should go very slowly when we postulate others. When you realize you're in one of these situations, it will sometimes make good moral sense to take into account differences, but not otherwise.
Here are Regan's override situations--
(1) Self defense.
(2) Punishment of the guilty.
(3) Innocent shields.
(4) Innocent threats.
(5) Prevention cases.
Human rights are overridable in these situations just as much as animal rights, and Regan talks mostly about human rights to explain cases (1) - (4). Thus, most of his discussion of how animal rights may be overridden focuses on prevention cases. But it's particularly when you focus on the whole list of override cases that you appreciate that he's talking about strange, exceptional circumstances.
"Prevention" is a technical term here. Not just any situation where a bad is to be prevented qualifies as a "prevention" case. Here's Regan's famous example--four men and a dog are in a lifeboat. There's too much weight and all will die if no one goes overboard. It's key to this being a special case that all on board are at risk--nobody's a bystander. Furthermore, if nothing is done, all will die. In that singular situation, Regan thinks we ought to pay attention to differences. We ought to throw a normal dog overboard rather than a healthy 25-year old human because (he says) the dog has less to lose.
Differences could enter into the other situations as well. Suppose we're in situation (3). Bad guys are shooting at us. They've deliberately surrounded themselves with innocents. May we take them out, even at risk of killing innocents? If we can, the next question is when to do it. Suppose (this is my example, not Regan's) they shoot from a nursery school in the morning and from a zoo in the afternoon. Regan would presumably say we should fire back in the afternoon. The animals have less to lose.
So Regan does think human-animal differences require us to prioritize human lives in some cases, but the crucial thing to see is that these are very singular cases. He does not think that human-animal differences make for differences in inherent value or the strength of human vs. animal rights. He doesn't think that, across the board, humans have priority over animals.
Suppose we are facing a plague that could kill a million human beings. It doesn't affect dogs at all. Scientists discover, however, that the liver of a dog contains a miraculous cure. By killing one dog, we can save a million. Can we do it? Definitely not, on Regan's view. This is not a prevention case, because the dog is not at risk. It's also not self-defense: the dog is not attacking us. It's not any of the override situations. The dog's right to be treated with respect protects him from being used to solve a problem that has nothing to do with him. You can even picture this scenario taking place on a sinking lifeboat, and Regan will still say the dog cannot be sacrificed. (See The Case for Animal Rights, pg. 385) Regan is an abolitionist about animal research: we should do none at all, no matter what.
Another situation that's "none of the above" is one in which we simply need to eat an animal to survive (the caveman example in my book). That's just like the research case, and isn't one of the five override cases. So Regan's theory does not permit him to think this is morally acceptable either. (And what matters is the theory. Oddly, and without enough explanation, he briefly defends eating animals for survival on pg. 351.)
My view, by contrast, is that human-animal differences do make across the board differences in how we may treat them. They do create differences in inherent value between different species, and they do affect how much respect we owe to members of different species. It's not just in the very peculiar override cases Regan discusses that differences matter.
How do they matter? Which differences matter? There's more on this in my book, but some readers will think: vague, not enough detail! Maybe I should have quoted Aristotle--"Our discussion will be adequate if we make things perspicuous enough to accord with the subject matter." I'm skeptical that any perfectly clear, detailed, and precise view about the grounds of respect would really be believable.