Three hundred years ago, slavery was widely accepted. That one human could enslave another was not viewed as something innately immoral. In Roman times, it was considered acceptable to have gladiators fight each other to the death for the enjoyment of the crowds. Many societies condoned human sacrifice. All of these practices, of course, are totally rejected by civilized society. Over at National Review, Matthew Scully argues that our carnivorous practice of meat consumption will go the same way.

Scully quotes an earlier article by noted columnist Charles Krauthammer: “surely some contemporary practices will be deemed equally abominable by succeeding generations. The only question is: Which ones? I’ve long thought it will be our treatment of animals. I’m convinced that our great-grandchildren will find it difficult to believe that we actually raised, herded, and slaughtered them on an industrial scale — for the eating.”

Whether or not Scully’s assumption that meat-eating will become the ethical equivalent of slavery and child sacrifice is true is irrelevant. The mere fact that society assumes something to be immoral does not, of course, make it so. But Scully’s arguments suffer from a deeper flaw. Throughout the article, he seems to blur the distinction between animal and human. “You don’t have to see comparisons to Dachau,” Scully writes, “to understand that all these little creatures deserve better than this.” Dachau, of course, was the first of the Nazi concentration camps.

There are, to be sure, legitimate arguments in favor of abstention from meat consumption. And, of course, cruelty to animals ought to be abhorred. Krauthammer, for his part, eloquently argues against trapping animals in zoos and aquariums for human enjoyment. But Krauthammer is careful to distinguish between man and animal. “I firmly believe that man is the measure of all things… I cringe at medical experimentation, but if you need to study cats’ eyes in order to spare some humans from blindness, do it.” It is this crucial distinction that distinguishes his argument from Scully’s.

As humans, we are responsible to treat animals with care, not cruelty. But the lines must not be blurred. Elevating animals to quasi-human status is but a small step to demoting other humans and considering them quasi-animals.