I’m surprised that so many people nowadays seem to misunderstand the proverb “honesty is the best policy.” They treat it as though it meant something like “honesty is good” or “you should always be honest.” It does not.
The word “policy” as used in the saying does not mean something generic like a way of acting. Instead “policy” here has its older sense of “advantageous conduct,” “prudence,” “cunning,” “shrewdness,” or “craftiness.” To say that “honesty is the best policy” is to recommend honesty on strategic rather than moral grounds.
Those who miss this will typically fail to understand the phrase when they come across it in contexts where it is used correctly, and they will be baffled by lines such as Richard Whately’s: “It is undoubtedly a just maxim, that in the long run ‘honesty is the best policy’; but he whose practice is governed by that maxim is not an honest man.”
Discussions of the phrase often credit Edwin Sandys for coining it (although he uses it as though it were already a common phrase), but miss the fact that he too is using it pejoratively, expressing the hope that “this over-politick and too wise order may reach a note higher than our gross conceits, who think honesty the best policy.”
I’m sure my linguistic-descriptivist readers (or at any rate those who think they are descriptivists; no one can actually be a consistent linguistic descriptivist, and what passes for descriptivism is really just an unargued democratised prescriptivism) will say “maybe the phrase used to have a purely strategic meaning, but it no longer does.” But in linguistic matters I am an epistocrat rather than a democrat. When a term or phrase has two uses, and one is generally favoured by those aware of both uses, while the other is generally favoured by those aware of only one, I reckon there is a (defeasible) presumption in favour of the informed users, even if the uninformed users are a majority. (This would be an example of the division of linguistic labour that Putnam talks about.)
Likewise, when a term or phrase has a very specific and useful meaning, I oppose wrecking it by giving it some watered-down and boring meaning that any number of other terms or phrases could suit as well, just as I would oppose wrecking a delicate precision screwdriver by using it as an icepick. (Hence my similar resistance to wrecking the meaning of “decimate.”)
An intelligent prescriptivism is not about resisting linguistic change at all costs; it is about resisting bad linguistic changes while embracing good ones. Those who favour avoiding “he” as the generic human pronoun, for example, are likewise prescriptivists, advocating change for good prescriptivist reasons. What Aristotle says about the judgments of the virtuous agent, what Hume says about the standard of aesthetic taste, and what Mill says about higher vs. lower pleasures are all good models for understanding proper linguistic prescriptivism.