Wittgenstein is in practice generally thought to be some variety of “Ordinary-Language” Philosopher, that is, a philosopher who takes ordinary language (as opposed to scientific language, to “technical” language, or to its bastard child, “super-scientific” (“metaphysical”) language) to be our keystone in philosophy; and who thinks that philosophy can proceed therefore by means of paying careful attention to the way we normally actually speak, and prohibiting uses that conflict with the way we normally actually speak.

And indeed, what “ordinary/everyday language” is taken to be opposed to is critical. The key point of this chapter is however to suggest, contra what still tends to be the prevailing wisdom, that the crucial mistake in “Wittgenstein studies” has generally been to misidentify the contrast class that Wittgenstein intended. I call it “the crucial” mistake, for the mistake has (had) enormous consequences, as I shall seek briefly to demonstrate.

We should begin with the single most important passage in Philosophical Investigations for understanding Wittgenstein's employment of the term “everyday”:

The first thing to say about this famous passage is that it opens with a question; and that the sentence that follows does not answer the question (or at least, does not “reveal” it to have been a merely rhetorical question).