4.06 Only thus can a sentence be true or false, in that it is a picture of reality.

Correspondence theory of truth again, presumably not being endorsed though, given Frege’s criticism of it and W’s own explicit rejection of it later (and, indeed, perhaps implicitly immediately above). It (or something very like it, cf. Glock) seems to be being endorsed here, but it is so only if “a picture of reality” means something, which presupposes that comparing a proposition with reality is an idea with sense. But has this idea been given any sense yet?