How does utilitarianism support Peter Singer’s argument for animal rights?

Peter Singer’s argument for animal rights is rooted in utilitarianism, an ethical framework that evaluates the morality of actions based on their ability to promote happiness or prevent pain.1

Singer advances his position through the principle of equal consideration of interests (PEC). This principle asserts that one must give equal weight in moral decision-making to the like interests of all beings affected by an action. Because both humans and many nonhuman animals are capable of experiencing pleasure and suffering, they share a fundamental interest in avoiding pain. Singer argues that the capacity to feel pain is the essential condition for having interests, and therefore, species membership is a morally irrelevant characteristic—much like race or sex.231

By applying this utilitarian standard, Singer contends that favoring human interests over the like interests of animals solely based on species is a form of speciesism—an irrational prejudice analogous to racism or sexism. Consequently, he maintains that all beings with interests deserve equal consideration, and it is ethically imperative to account for animal suffering in our moral decisions.213