Peter Singer on the Interests of Animals

Quote

"The capacity for suffering and enjoyment is a prerequisite for having interests at all."

— Peter Singer, Animal Liberation, Chapter 1 (1975)

Historical Context

The sentence appears at the beginning of Animal Liberation (1975), in the opening chapter where Singer lays out the philosophical foundations of his argument. The book was written at the height of the animal liberation movement and against the background of the rapid industrialization of animal agriculture, which in the decades after the Second World War had transformed farming into a system of mass confinement. Singer's aim was not merely to document cruelty — though the book does that with grim detail — but to show that the treatment of animals is a moral question that the dominant ethical traditions had failed to take seriously. To do that, he needed to establish that animals have moral standing, that their interests count in moral deliberation, and he needed a criterion for having interests that would not beg the question against them.

The sentence is the criterion. Singer's argumentative strategy is to find a ground of moral standing that is neither species-specific nor intellectualist — that does not quietly assume that only beings with language, reason, or a soul can matter morally. His candidate is sentience: the capacity to suffer and to enjoy. The claim that this capacity is a "prerequisite for having interests" is the foundation stone of the entire theory, because interests are the currency of moral argument: to say that a being has interests is to say that how it fares matters, that its well-being can be affected by what we do. Singer's move was to tie the possession of interests to the capacity for felt experience rather than to rationality, self-consciousness, or species membership.

Philosophical Interpretation

The sentence does two things. First, it identifies the ground of moral standing: interests. A being has an interest in something when that thing affects its welfare — when it can be better or worse off. Second, it gives the criterion for having interests: the capacity for suffering and enjoyment. A being that cannot suffer and cannot enjoy is not harmed by being made to suffer, and is not benefited by being made happy; its welfare is simply not at stake. On this criterion, a rock has no interests, a plant has no interests in any morally demanding sense, but any being capable of pain — a dog, a pig, a mouse — has interests, because pain is a harm to it whatever its species.

The philosophical work of the sentence is to make the boundary of moral concern turn on a capacity that animals share with us. Singer is careful to distinguish the capacity for suffering from the capacity for self-consciousness or the possession of a concept of a self with a past and future. The latter capacities may matter for the right to life, he argues, but they are not prerequisites for the moral significance of suffering. Pain is pain, whether it is felt by a human being or by a laboratory rat, and the principle of equal consideration of interests requires that comparable suffering count equally. This is the point of the sentence: because animals can suffer and enjoy, they have interests, and because they have interests, the utilitarian calculation must include them. The conclusion is that the routine infliction of suffering on animals in factory farms and laboratories stands in need of justification — and, in Singer's judgment, for the most part cannot be justified.

Related Concepts

The quote states the sentience criterion for moral standing — the claim that the capacity for suffering and enjoyment is what makes a being's welfare matter. It supports the principle of equal consideration of interests, which requires that the interests of all affected beings count equally. The argument connects to speciesism, the bias against the interests of other species, and to animal rights, the stronger conclusion drawn by some of Singer's successors. It also engages the utilitarian framework of weighing harms and benefits, and the expansion of the moral circle as the historical pattern of moral progress.

Learning Path

Begin with the site's answer on what animal rights is, and the companion page on speciesism, which define the terms of the debate. Read the site's answer on what utilitarianism is to understand the framework of Singer's argument. Then explore the expanding circle of moral concern and the question of where the boundary of moral standing should be drawn — a question that now extends to debates about artificial intelligence and the moral status of possible nonhuman minds.