Peter Singer on the Expanding Circle

The circle of altruism has broadened from the family and tribe to the nation and race, and we are beginning to recognize that our obligations extend to all human beings. The process should not stop there. In my earlier book, Animal Liberation, I showed that it is as arbitrary to restrict the principle of equal consideration of interests to our own species as it would be to restrict it to our own race. The only justifiable stopping place for the expansion of altruism is the point at which all whose welfare can be affected by our actions are included within the circle of altruism. This means that all beings with the capacity to feel pleasure or pain should be included; we can improve their welfare by increasing their pleasures and diminishing their pains.

The expansion of the moral circle should therefore be pushed out until it includes most animals. (I say “most” rather than “all” because there comes a point as we move down the evolutionary scale—oysters, perhaps, or even more rudimentary organisms—when it becomes doubtful if the creature we are dealing with is capable of feeling anything.) From an impartial point of view, the pleasures and pains of non-human animals are no less significant because the animals are not members of the species Homo sapiens. This does not mean that a human being and a mouse must always be treated equally, or that their lives are of equal value. Humans have interests—in ideas, in education, in their future plans—that mice are not capable of having. It is only when we are comparing similar interests—of which the interest in avoiding pain is the most important example—that the principle of equal consideration of interests demands that we give equal weight to the interests of the human and the mouse.

The expansion of the moral circle to non-human animals is only just getting under way. It has still to gain verbal and intellectual acceptance, let alone be generally practiced. Yet the ecology movement has emphasized that we are not the only species on this planet, and should not value everything by its usefulness to human beings; and defenders of rights for animals are gradually replacing the old-fashioned animal welfare organizations which cared a lot for domestic pets but little for animals with less emotional appeal to us. In philosophy departments all over the English-speaking world, the moral status of animals has become a lively topic of debate, and the number of those calling for a change in our present attitude toward animals is growing. The idea of equal consideration for animals strikes many as bizarre, but perhaps no more bizarre than the idea of equal consideration for blacks seemed three hundred years ago. We are witnessing the first stirrings of a momentous new stage in our moral thinking.

(Peter Singer, The Expanding Circle: Ethics and Sociobiology [New York and Scarborough, Ontario: New American Library, 1982], 120-1 [first published in 1981])