Abstract

According to liberal egalitarian morality, all human beings are one another's moral equals. Nonhuman animals, by contrast, are not considered to be our moral equals. This essay considers two challenges to the liberal egalitarian view. One is the ``separation problem,'' which is the challenge to identify a morally significant intrinsic difference between all human beings and all nonhuman animals. The other is the “equality problem,” which is to explain how all human beings can be morally equal when there are some human beings whose psychological capacities are no higher than those of certain nonhuman animals. The focus throughout is on the ethics of killing but the arguments are of broader relevance. The essay reaches a skeptical conclusion about our ability to meet these challenges.