 It is held that what we ought to do is that action, among all that are possible, which [is likely on the available evidence] to produce the best results on the whole [according to some contextually specified standard of goodness]; and this is regarded as constituting a definition of ought. I hold that this is not a definition, but a significant proposition … It might be proved, in the course of moral exhortation, that such and such an action [is likely on the available evidence to] have the best results [according to some contextually specified standard of goodness]; and yet the person exhorted might inquire why he should perform the action. The exhorter would have to reply: “Because you ought to do what [is likely to] have the best results [according to some contextually specified standard of goodness].” And this reply distinctly adds something. The same arguments by which good was shown to be indefinable can be repeated here, mutatis mutandis, to show the indefinability of ought. (RoE: 101/Papers 4: 573, somewhat modified)