“ Never show a child what he cannot see. Since mankind is almost unknown to him, and since you cannot make a man of him, bring the man down to the level of the child. ”
 Jean-Jacques Rousseau, Emile, or On Education (1762). copy citation

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“It is easy to convince a child that what you wish to teach him is useful, but it is useless to convince if you cannot also persuade. Pure reason may lead us to approve or censure, but it is feeling which leads to action, and how shall we care about that which does not concern us? Never show a child what he cannot see. Since mankind is almost unknown to him, and since you cannot make a man of him, bring the man down to the level of the child. While you are thinking what will be useful to him when he is older, talk to him of what he knows he can use now. Moreover, as soon as he begins to reason let there be no comparison with other children, no rivalry, no competition, not even in running races.” source