  Of course, this proposal by Hare makes salient what has always been the gravest objection to a prescriptivist analysis of practical “ought”s (and “must”s): moral judgments cannot entail imperatives; for the content of a moral judgment can occur, whereas an imperative cannot occur, embedded in various contexts, such as an “if”-clause (forming a conditional antecedent), or a “that”-clause (giving the content of a belief or assertion). The objection was made strongly by Peter Geach in an article (1965) citing Gottlob Frege; so it has come to be known as the “Frege-Geach” objection.  Hare’s response is to be found in Hare (1970). His solution to the problem as it arises with conditionals derives from Gilbert Ryle’s notion of “inference tickets” (1950). The role of the quasi-English “If get drunk every evening, work in a bar” is to yield an implicit prescription to work in a bar out of any prescription to get drunk every evening. To press the utterer of (a) on what he is hypothesizing, and what might make it true, is therefore out of place. What looks like a truth-apt proposition with a complex structure is really playing a quite different role: it is not a proposition, but a kind of rule.