b. “If the opinion of which I have now stated is psychologically true, if human nature is so constituted as to desire nothing which is not either a part of happiness or a means of happiness, we can have no other proof, and we require no other, that these are the only things desirable. If so, happiness is the sole end of human action, and the promotion of it the test by which to judge of all human conduct; from whence it is necessarily follows that it must be the criterion of morality, since a part is included in the whole. And now to decide whether this is really so; whether mankind do desire nothing for itself but that which is a pleasure to them, or of which the absence is pa pain we have evidently arrived at a question of fact and experience, dependent, like al similar questions, upon evidence . . . . “ (Utilitarianism, ch. IV)
