The first time I opened Peter Singer’s Animal Liberation, I was dining alone at the Palm, trying to enjoy a rib-eye steak cooked medium-rare. If this sounds like a good recipe for cognitive dissonance (if not indigestion), that was sort of the idea. Preposterous as it might seem, to supporters of animal rights, what I was doing was tantamount to reading Uncle Tom’s Cabin on a plantation in the Deep South in 1852.
Singer and the swelling ranks of his followers ask us to imagine a future in which people will look back on my meal, and this steakhouse, as relics of an equally backward age. Eating animals, wearing animals, experimenting on animals, killing animals for sport: all these practices, so resolutely normal to us, will be seen as the barbarities they are, and we will come to view “speciesism”—a neologism I had encountered before only in jokes—as a form of discrimination as indefensible as racism or anti-Semitism.
Even in 1975, when Animal Liberation was first published, Singer, an Australian philosopher now teaching at Princeton, was confident that he had the wind of history at his back. The recent civil rights past was prologue, as one liberation movement followed on the heels of another. Slowly but surely, the white man’s circle of moral consideration was expanded to admit first blacks, then women, then homosexuals. In each case, a group once thought to be so different from the prevailing “we” as to be undeserving of civil rights was, after a struggle, admitted to the...