The author examines W.V.O. Quine's theory of the origin of moral values as presented in 'On the nature of moral values'. He points to some rather evident shortcoming of that theory. He is particularly worried by its vagueness and a deficient definition of altruism in Quine's theory. Then he tries to find out if it is possible to keep Quine's initial assumptions--especially behaviourism and naturalism--but clarify the vagueness and adopt a more satisfactory view of altruism.