If 'good' functions as an optative in unasserted contexts (e.g., premise (i)) but as a different semantic kind in asserted contexts (e.g., premise (ii)), then 'good' shifts meaning within the same argument
optative(Used to characterize how non-cognitivist theories treat evaluative terms in embedded/unasserted positions)
A semantic kind for expressions like 'X is good' when used in unasserted contexts, where the expression functions as an expression of desire or wish rather than a truth-apt claim
unasserted contexts(Philosophy of language and logic)
Linguistic contexts in which a sentence appears without being directly asserted, such as the antecedent of a conditional (e.g., 'If stealing is wrong, then getting others to steal is wrong')
In this argument “X is good” would have one meaning in premise (i)—in which it would be an optative—and another in premise (ii)—in which it would be a creature of some other semantic kind. (I have emphasized the point by putting the first occurrence in italics and the second in bold.) But an argument is only valid if the words involved retain the same meanings throughout the inference. If not, we have an instance of the fallacy of equivocation. So it looks as if any attempt to deal with Geach’s