There is always a certain difficulty involved in the instruction of young people, and it is this: the knowledge one imparts to them is such that one finds oneself constrained to outstrip their years. Without waiting for their understanding to mature, one is obliged to impart knowledge to them, which, in the natural order of things, can only be understood by minds which are more practised and experienced. It is this which is the source of the endless prejudices of the schools – prejudices which are more intractable and frequently more absurd than ordinary prejudices. And it is this, too, which is the source of that precocious prating of young thinkers, which is blinder than any other self-conceit and more incurable than ignorance. This difficulty, however, is one which cannot be entirely avoided, and the reason is this. In an epoch which is characterised by an elaborately complex social organisation, a knowledge of higher things is regarded as a means to advancement and comes to be thought of as a necessity of life. Such knowledge ought by nature, however, really to be regarded merely as one of life's adornments – one of life's inessential beauties, so to speak. Nonetheless, even in this branch of instruction, it is possible to make public education more adapted to nature, even though it will not be possible to bring it into perfect harmony with it. The natural progress of human knowledge is as follows: first of all, the understanding develops by using experience to arrive at intuitive judgements, and by their means to attain to concepts. After that, and employing reason, these concepts come to be known in relation to their grounds and consequences. Finally, by means of science, these concepts come to be known as parts of a well-ordered whole. This being the case, teaching must follow exactly the same path. The teacher is, therefore, expected to develop in his pupil firstly the man of understanding, then the man of reason, and finally the man of learning. Such a procedure has this advantage: even if, as usually happens, the pupil should never reach the final phase, he will still have benefitted from his instruction.