Its mind would henceforth be accustomed to thoroughness and clearness; the child would rely on its own judgment, and be free from prejudices. And, in general, children should not get to know life, in any aspect whatever, from the copy before they have learnt it from the original. Instead, therefore, of hastening to place mere books in their hands, one should make them gradually acquainted with things and the circumstances of human life, and above everything one should take care to guide them to a clear grasp of reality, and to teach them to obtain their ideas directly from the real world, and to form them in keeping with it--but not to get them from elsewhere, as from books, fables, or what others have said--and then later to make use of such ready-made ideas in real life. The result will be that their heads are full of chimeras and that some will have a wrong comprehension of things, and others will fruitlessly endeavour to remodel the world according to those chimeras, and so get on to wrong paths both in theory and practice. For it is incredible how much harm is done by false notions which have been implanted early in life, only to develop later on into prejudices; the later education which we get from the world and real life must be employed in eradicating these early ideas. And this is why, as is related by Diogenes Laertius, Antisthenes gave the following answer: έρωτηθεις τι των μαθηματων ἀναγκαιοτατον, έφη, "το κακα ἀπομαθειν." (_Interrogatus quaenam esset disciplina maxime necessaria, Mala, inquit, dediscere_.) * * * * * Children should be kept from all kinds of instruction that may make errors possible until their sixteenth year, that is to say, from philosophy, religion, and general views of every description; because it is the errors that are acquired in early days that remain, as a rule, ineradicable, and because the faculty of judgment is the last to arrive at maturity. They should only be interested in such things that make errors impossible, such as mathematics, in things which are not very dangerous, such as languages, natural science, history, and so forth; in general, the branches of knowledge which are to be taken up at any age must be within reach of the intellect at that age and perfectly comprehensible to it. Childhood and youth are the time for collecting data and getting to know specially and thoroughly individual and particular things. On the other hand, all judgment of a general nature must at that time be suspended, and final explanations left alone. One should leave the faculty of judgment alone, as it only comes with maturity and experience, and also take care that one does not anticipate it by inculcating prejudice, when it will be crippled for ever.