Again, my aim is not to say that using a word to mean one thing is "right" and using it to mean something else is "wrong" in some Platonic sense. It is, rather, to say that if you're not aware of what, exactly, the accepted usage is (and what less-widely-known usages are available, if any), and simply use words or phrases because you've heard them used in some vaguely similar context, then you will not be communicating what you think you're communicating, and that, furthermore, you may be unaware of the existence of certain conceptual categories.

Also, I see your two years' worth of Language Log posts and raise you the Less Wrong sequence "A Human's Guide to Words". "Words mean whatever people mean by them" is of no use for both effective communication and for using language as a tool to aid in cognition.

Many of the commenters here have taken my post to mean that I wish to legislate correct usage, or something to this effect. This is a failure on my part, in that I have not successfully conveyed my point, which I consider fairly straightforward, and will now attempt to briefly clarify:

Precision and accuracy are two different concepts. If we want to discuss them effectively, and also (this is sometimes overlooked) if we want to think about them effectively, then it helps quite a bit to have two different words for them. There is no intrinsic, fundamental reason why we absolutely must use "precise" to mean 'precise' and "accurate" to mean 'accurate', instead of vice versa. But given that we already have two words, is there any good reason not to say "precise" when you mean 'precise' and "accurate" when you mean 'accurate', rather than something else?

The Language Log article you linked in your other comment has this quote, which I more or less endorse:

And there are plenty of people of all political persuasions who have a passing concern about usage but don't find the diatribes of the right-wing critics particularly compelling (or the ones of the linguists, either, in my experience) — people who are genuinely attached to the distinction between disinterested and uninterested, but who are uncomfortable about using words like "permissiveness" and "the erosion of standards," and who are affronted by the condescending derision of minority dialects. As Lionel Trilling once put it, "I find righteous denunciations of the present state of the language no less dismaying than the present state of the language." But it's difficult to make a case for language criticism nowadays without irony — you wind up saying things like, "Well, I personally don't use disinterested to mean "uninterested," and I'm sorry that this one is going by the boards, since at a certain point I can't use disinterested with any assurance that most of my audience will get what I mean, but I for sure don't think it signals the end of civilization as we know it. What's for lunch?"