The world's foremost proponent of infanticide, Peter Singer, argues in the Guardian
in favor of granting legal rights to great apes
and perhaps other animals. Among the rights these animals should possess, he claims, is the right to life. Yet, the same Peter Singer has written that killing a baby is no more problematic morally than killing a fish since neither are, in his view, "persons." I wonder if Singer would support ape infanticide? He does support ape euthanasia, of course. Just as he does people with Alzheimer's.
Singer also wants to grant a right not to be "tortured." Of course, such a right would only apply against humans. If a pack of chimpanzees attacked another pack, torturing and killing, as sometimes happens--no one would suggest that they be "punished" for the "crime," since no crime would have occurred. If humans did that, it would be immoral and criminal, not only because of the pain caused to the animals but because the act amounts to lower than human action. Similarly, if a lion tore a chimp apart, Singer would not suggest that the lion face trial and imprisonment. This is because neither chimps nor lions are moral beings. (Singer's suggestion that apes resent not having favors returned, and so have a sense of justice, is hardly equivalent.)
Of course, we should punish any human who tortures an animal. That is because we are the only beings in the known universe who can--and should--be held accountable for our actions. But the issue Singer is interested in isn't really preventing torture, properly understood, but rather at interfering with necessary medical research.
Singer claims that great apes are not used in research any more. But chimps were unquestionably needed to create the Hepatitis vaccine. It appears increasingly likely that HIV came from chimpanzees
who harbor a very similar virus (SIV) and yet, don't get sick from it. This means there is undoubtedly much to learn from performing humane experiments on these wonderful animals to help us find effective treatments or a vaccine for HIV, as two examples.
I don't believe we should use chimps in research lightly. But in an appropriate case to prevent substantial human harm or promote substantial human benefit, and when there is no other reasonable choice, we need to be free to experiment on these wonderful animals--subject always to proper standards of care.