In a series of early essays, beginning with "Must We Mean What We Say?", Stanley Cavell offers a sustained response to the argument that ordinary language philosophy is nothing more than amateur linguistics, carried out from the armchair -- so that philosophers' claims about "what we say", and what we mean when we say it, are necessarily in need of proper empirical support. The present paper provides a close reading of Cavell and a defense of his argument that, since a (...) philosopher's descriptions of our use of words are supposed to be an expression of *self*-knowledge, they do not require, and indeed cannot possibly find, any empirical justification. This does not guarantee that these descriptions are immune to error, nor does it mean they describe a different range of facts from the ones that are the subject-matter of linguistics and lexicography. Nor, finally, does it follow from this argument that observation of the facts of ordinary usage, as revealed e.g. in linguistic corpora, is of no use to the philosopher of ordinary language. I close with a brief discussion of what the shared nature of linguistic communication shows about how to understand the "we" in "what we say". (shrink)