Jean-Jacques Rousseau said this quote

“ Hold childhood in reverence, and do not be in any hurry to judge it for good or ill. Leave exceptional cases to show themselves, let their qualities be tested and confirmed, before special methods are adopted. Give nature time to work before you take over her business, lest you interfere with her dealings. You assert that you know the value of time and are afraid to waste it. You fail to perceive that it is a greater waste of time to use it ill than to do nothing, and that a child ill taught is further from virtue than a child who has learnt nothing at all. You are afraid to see him spending his early years doing nothing. What! is it nothing to be happy, nothing to run and jump all day? He will never be so busy again all his life long. Plato, in his Republic, which is considered so stern, teaches the children only through festivals, games, songs, and amusements. It seems as if he had accomplished his purpose when he had taught them to be happy; and Seneca, speaking of the Roman lads in olden days, says, They were always on their feet, they were never taught anything which kept them sitting. Were they any the worse for it in manhood? Do not be afraid, therefore, of this so-called idleness. What would you think of a man who refused to sleep lest he should waste part of his life? You would say, He is mad; he is not enjoying his life, he is robbing himself of part of it; to avoid sleep he is hastening his death. Remember that these two cases are alike, and that childhood is the sleep of reason.The apparent ease with which children learn is their ruin. You fail to see that this very facility proves that they are not learning. Their shining, polished brain reflects, as in a mirror, the things you show them, but nothing sinks in. The child remembers the words and the ideas are reflected back; his hearers understand them, but to him they are meaningless.Although memory and reason are wholly different faculties, the one does not really develop apart from the other. Before the age of reason the child receives images, not ideas; and there is this difference between them: images are merely the pictures of external objects, while ideas are notions about those objects determined by their relations. ”