Peter Singer grapples with this quandary as with all the other challenges so far issued. One doesn't write a galvanising philosophical treatise without covering all the bases simply because there are a legion of academic critics poised to sink their teeth (no puns) into one, bearing pens tipped with poison. I noted this in my opening post that set the murtadeen achatter:http://www.councilofexmuslims.com/index.php?topic=12576.msg349470#msg349470
Endeavour to procure the book 'cause it saves one a good deal of time that might be profitably channelled into sending hate mail to my wife so we may have angry sex when she returneth.
Galloping on to your query ...
Agreed, the trousered ape has been dismembering animal flesh with vim and gusto since the first advanced gorilla put on knickers, organised a hunting pack, and set out to collar a delicious meal. Conversely, for countless eons primitive man was ferociously hunted by much bigger and more powerful land animals in a titanic forest-shaking struggle for supremacy that makes all other battles appear like a family squabble. Man, for so long a time the hunted, became the triumphant hunter.
But one finds it curious in the extreme that men should contend that we model our moral behaviour on savage beasts in light of the fact we consider them so morally inferior as to be fit only for slaughter. More to the point, wild beasts are so biologically constructed that they can do no other but to feed on flesh. Humans, more cerebrally developed, can survive without meat. Men's carnivorous diet is the residual artifact of our hunter-gathering phase.
In his capacity to display moral concern for the welfare of unrelated beings man is morally superior to most (though perhaps not all) living creatures. Is this an instance of speciesism? No, it is a recognition of scientific fact. In connection with some higher primates man, by virtue of the complexity of his emotional life, the depth of his compassion, the sophistication of his (tragically flawed) ethical code, occupies a superior moral plane that is one of degree, and not kind. How then may we define speciesism? Like racism and sexism, it is predicated on the notion that because a class of beings do not belong to our tribe, our sex, our race, our nation, our species, they are entitled to little moral concern.
Ethics invites us to extend the sphere of our moral circle to encompass previously excluded groups. One by one man has slowly but surely admitted formerly subject people into his domain of moral concern driven in living memory by movements like the suffragettes and the civil rights struggle. Animal Liberation invites us to extend our moral circle, ever expanding and ever dynamic, anew.