But humans differ from animals in morally significant ways. Yes they do, Singer readily acknowledges, which is why we shouldn’t treat pigs and children alike. Equal consideration of interests is not the same as equal treatment, he points out; children have an interest in being educated, pigs in rooting around in the dirt. But where their interests are the same, the principle of equality demands they receive the same consideration. And the one all-important interest humans share with pigs, as with all sentient creatures, is an interest in avoiding pain.
