Peter Singer is a professor of philosophy at Princeton University who is has famously made a case for legalizing infanticide and who is also well-known for his advocacy of animal rights. In the recent issue of Free Inquiry, the organ of the Council for Secular Humanism, Singer chides his fellow humanists for their overall failure to shed the prejudice of speciesism which, he claims, has been inherited from Christian forebears.
He writes that Christians believe that "God gave human beings dominion over the natural world, and God doesn't care how we treat it....Nature itself is of no intrinsic value," in the Christian view, "and the destruction of plants and animals cannot be sinful." This, of course, is the sheerest flapdoodle, but more on that later.
Singer chastises humanists for holding to the Christian idea that humans are at the center of the moral universe and for thinking that values are grounded in the welfare of humans rather than in the "welfare of all beings capable of having a welfare at all." There is, Singer asserts, "no non-religious reason why the pains and pleasures of non-human animals should not be given equal [moral] weight with the similar pains and pleasures of human beings."
As an atheistic Darwinian, this is a very peculiar argument for the Princeton professor to make. It may be that there's no non-religious reason for not treating animals as the moral equal of humans, but the salient point is that there's no non-religious reason why one should do it. Searching the article for reasons why he believes humanists are wrong to exploit animals, the only thing one finds is his claim that they should reject this sort of behavior because it's based upon Christian dogma and, the implication is, anything Christian is ipso facto wrong.
Singer is in an awkward position here. He wants to make the case that exploitation of animals is immoral, but as a Darwinian he has no basis for making such a claim. What grounds does Darwinian survival of the fittest give us for condemning the mistreatment of animals? The only ethic one can derive from evolution is that one should look out for one's own interests. The principles of evolution are silent, as they must be, about the means employed to insure one's survival. If human survival is accomplished through behaviors that involve cruelty to other creatures, evolution affords us no basis for passing judgment. Darwinian evolution, to the extent that it endorses any ethic over any other, simply endorses the view that might makes right.
Singer's complaint against the mistreatment of animals distills to this: He likes animals and it makes him sad to see them treated badly, and he wishes others would feel the way he does. As an atheist that's the most he can say. To suggest that others are immoral if they don't feel the way he does is silly. Indeed, an animal abuser could reply that it is Singer who is immoral for not believing that animals should be killed for sport and pleasure, and his argument would be no less compelling than Singer's.
One of the oddities of what people like Singer are trying to do is that in seeking to convince people that they should discard every vestige of religious dogma, they make it clear that they themselves wish to retain the concept of moral judgment. Yet moral judgment is incoherent apart from religious assumptions, specifically the assumption that there exists a personal God.
It needs to be stressed that the only basis we have for saying that it is wrong to treat animals unkindly is the Christian doctrine that animals, and nature in general, belong to God who has given us stewardship over them. He grants us the right to derive pleasure from them in various ways, but he expects us to treat them with respect and care and to avoid inflicting gratuitous pain and harm. We have, therefore, an obligation, a moral obligation, to be diligent in our care of his creation.
We're in the position of the babysitter who has been told to feel free to help herself to the refrigerator, but such a privilege does not entitle her to go on a destructive rampage throughout the house. Take away the belief that God exists and has made us stewards over his creation, however, and adopt instead the view that all of life is just an amazing fluke in a vast, empty cosmos, and the notion that there exists some imperative to treat animals, or other humans for that matter, in any particular way becomes ludicrous.