Grimm wrote:If someone shows up naked, that is clearly incorrect...
In this circumstance I think we could exchange "appropriate" for "correct" - and I would think of "appropriate" as being closer to the relative and subjective sense you've described. To me, "correct" has more of the implication of a tick or cross in a schoolbook, that is with an underlying notion of there being a recognizably "right" form. I think I would be more likely to say "He was dressed inappropriately for the party" than "He was dressed incorrectly..." How would you say appropriate and correct differ? Would you use them very differently, in the area of dress or language?
JeffQyzt wrote:we share a set of common landmarks in a sea of linguistic variation; "correct" use in a language is a consensus, not an absolute.
This is getting into philosophy of language rather than mere grammar, and I don't claim much knowledge of that. I think your comments, though, raise the question of who is involved: a consensus within which group? Not amongst, I presume, all speakers of a language. Language does change over time and space but there are, despite that, attempts to identify correct usages: plenty of books on spelling and grammar exist. If I want to identify a "correct" usage I don't appeal in some way to the consensus but look up a book. There are also widely used forms that I would call incorrect, and the fact that some consensus exists over their use - by which I mean, lots of people use them - does not make me think that they are correct: for example, "I should of known" is not uncommon but I would call it incorrect.