Haus W.

"My German engineer, I think, is a fool [...] He thinks nothing empirical is knowable-I asked him to admit that there was not a rhinoceros in the room, but he wouldn't."
—B. Russell (letter to Lady Ottoline Morell, on meeting Wittgenstein)

"My propositions are elucidatory in this way: he who understands me finally recognizes them as senseless, when he has climbed out through them, on them, over them. (He must so to speak throw away the ladder, after he has climbed up on it.)"
—L. Wittgenstein (Tractatus Logico-Philosophicus)