"It is necessary to be given the prop that all elementary props are given." This is not necessary because it is even impossible. There is no such pro… - Ludwig Wittgenstein

"Tell me," Wittgenstein's asked a friend, "why do people always say, it was natural for man to assume that the sun went round the earth rather than that the earth was rotating?" His friend replied, "Well, obviously because it just looks as though the Sun is going round the Earth." Wittgenstein replied, "Well, what would it have looked like if it had looked as though the Earth was rotating?"

Der Satz der Mathematik drückt keinen Gedanken aus.

That ∨, ⊃, etc., are not relations in the sense of right and left, etc., is obvious.