I do have a question regarding marginal cases. Do all 'innocent' humans have a right to life? For instance, why would a severely mentally retarded person (with mental capabilities similar to a dog), have a right to life, and the dog not?
Good question, Jeff. Any other questions?
Note that we are talking about somebody who is super-retarded. Not somebody who will learn to talk and read a little bit and maybe get a job cleaning up at McDonald's or bagging groceries. But somebody who doesn't have the cognitive capacity to speak, to understand more than a few words, to tell time, or probably even dress himself.
In principle, I think that Society Girl has a valid point when she says that "The libertarian principles that I have read on this blog and elsewhere, taken to there ultimate conclusion, should lead Cheerful to say the answer is 'a severely mentally retarded person has less rights.'"
Well, of course such a person has "less rights." An individual so limited is never going to learn to drive or live independently. Left to his own devices, like a normal adult, he will die in the streets. The question is whether he has more rights than a dog or other animal of equivalent mental capacity. As a first approximation, I think that Society Girl has a point. My conception of rights is based on mental capacity, and a severely retarded person with the mental capacity of a dog should, you could argue, have the same rights as the animal.
But libertarianism -- my version, at least -- is also a political theory, a theory about the rules necessary to govern the state. I would argue that all members of the species homo sapiens should have the right not to be killed, even if, in individual cases, they fall below the threshold of sapience. The reason I argue that is that I don't trust government officials to accurately make a determination that somebody really only has the mental capacity of a dog. In general I think we should err on giving more rights to the mentally retarded, because I don't trust the government to make accurate determinations in individual cases.
I will add that I think that if we ever manage to genetically engineer more intelligent chimps or gorillas, as in David Brin's "Uplift" novels, I do think they should have the same rights as humans. Likewise aliens of equivalent intelligence, or sapient artificial life forms.
Let me also respond to anonymous commenter who seems shocked by the whole discussion:
Yipes! If Libertarians have not worked out for themselves why (or whether) we ought not to torture animals for pleasure or profit it seems that some remedial homework is in order.
Well, I have worked it out for myself -- personally I refrain from torturing animals for pleasure or profit. Largely because it doesn't bring me any pleasure, and I have yet to come up with a way to make it pay. I suspect that very few libertarians actually favor animal torture. The question is whether the power of the state ought to be used to prevent it, and I honestly think that is a hard question.