Tu cause, tu cause…
From Wittgenstein's Zettel—
413. One man is a convinced realist, another a convinced idealist and teaches his children accordingly. In such an important matter as the existence or non-existence of the external world they don't want to teach their children anything wrong. What will the children be taught? To include in what they say: "There are physical objects" or the opposite? If someone does not believe in fairies, he does not need to teach his children "There are no fairies": he can omit to teach them the word "fairy". On what occasion are they to say: "There are . . ." or "There are no . . ."? Only when they meet people of the contrary belief.
414. But the idealist will teach his children the word "chair" after all, for of course he wants to teach them to do this and that, e.g. to fetch a chair. Then where will be the difference between the idealist-educated children and the realist ones? Won't the difference only be one of battle cry?