Abstract

I argue that No-Ought-From-Is (in the sense that I believe it) is a relatively trivial affair. Of course, when people try to derive substantive or non-vacuous moral conclusions from non-moral premises, they are making a mistake. But No-Non-Vacuous-Ought-From-Is is meta-ethically inert. It tells us nothing about the nature of the moral concepts. It neither refutes naturalism nor supports non-cognitivism. And this is not very surprising since it is merely an instance of an updated version of the conservativeness of logic (in a logically valid inference you don’t get out what you haven’t put in): so long as the expressions F are non-logical, you cannot get non-vacuous F-conclusions from non-F premises. However, the triviality of No-Non-Vacuous-Ought-From-Is is important and its non-profundity profound. No-Ought-From-Is is widely supposed to tell us something significant about the nature of the moral concepts. If, in fact, it tells us nothing, this is a point well worth shouting from the housetops. This brings me to my dispute with Gerhard Schurz who has proved a related version of No-Ought-From-Is, No-Ought-Relevant-Ought-From-Is, a proof which relaxes my assumption that ‘ought’ should not be treated as a logical constant. But if ought is not a logical expression then it does not really matter much that No-Ought-From-Is would be salvageable even if it were. Furthermore, Schurz’s proof depends on special features of the moral concepts and this might afford the basis for an abductive argument to something like non-cognitivism. As an error theorist, and therefore a cognitivist, I object. Finally I take a dim view of deontic logic. Many of its leading principles are false, bordering on the nonsensical, and even the reasonably plausible ones are subject to devastating counter-examples.