J. S. Mill's “Proof” Of The Principle Of Utility

Abstract

In Chapter 4 of his essay Utilitarianism, “Of what sort of Proof the Principle of Utility is susceptible,” J. S. Mill undertakes to prove, in some sense of that term, the principle of utility. It has very commonly been argued that in the course of this “proof” Mill commits two very obvious fallacies. The first is the naturalistic fallacy (the fallacy of holding that a value judgment follows deductively from a purely factual statement) which he is held to commit when he argues that since “the only proof capable of being given that an object is visible, is that people actually see it. The only proof that a sound is audible is that people hear it: and so of the other sources of our experience. In like manner … the sole evidence it is possible to produce that anything is desirable, is that people do actually desire it.”1 Here Mill appears to hold that “X is desirable (=fit or worthy to be desired)”—a value judgment—follows deductively from “People desire x”—a factual statement. And the second is the fallacy of composition (i.e. an illicit transition from a statement about each several member of a collection to a statement about the collection as a whole) which seems to be involved in Mill'zs argument that since “each person's happiness is a good to that person … the general happiness (is), therefore, a good to the aggregate of all persons.”2