§ 20. That we must proceed from the known to the unknown is something more than a corollary to the above;[193] because not only are new concepts formed by the combination of old, but the mind has a liking for what it knows, and this liking extends itself to all that can be connected with its object. The principle of using the known in teaching the unknown is so simple, that all teachers who really endeavour to make anything understood, naturally adopt it. The traveller who is describing what he has seen and what we have not seen tells us that it is in one particular like this object, and in another like that object, with which we are already familiar. We combine these different concepts we possess, and so get some notion of things about which we were previously ignorant. What is required in our teaching is that the use of the known should be employed more systematically. Most teachers think of boys who have no school learning as entirely ignorant. The least reflection shows, however, that they know already much more than schools can ever teach them. A sarcastic examiner is said to have handed a small piece of paper to a student and told him to write _all he knew_ on it. Perhaps many boys would have no difficulty in stating the sum of their school-learning within very narrow limits, but with other knowledge a child of five years old, could he write, might soon fill a volume.[194] Our aim should be to connect the knowledge boys bring with them to the schoolroom with that which they are to acquire there.[195] I suppose all will allow, whether they think it a matter of regret or otherwise, that hardly anything of the kind has hitherto been attempted. Against this state of things I cannot refrain from borrowing Mr. Spencer’s eloquent protest. “Not recognising the truth that the function of books is supplementary—that they form an indirect means to knowledge when direct means fail, a means of seeing through other men what you cannot see for yourself, teachers are eager to give second-hand facts in place of first-hand facts. Not perceiving the enormous value of that spontaneous education which goes on in early years, not perceiving that a child’s restless observation, instead of being ignored or checked, should be diligently ministered to, and made as accurate and complete as possible, they insist on occupying its eyes and thoughts with things that are, for the time being, incomprehensible and repugnant. Possessed by a superstition which worships the symbols of knowledge instead of the knowledge itself, they do not see that only when his acquaintance with the objects and processes of the household, the street, and the fields, is becoming tolerably exhaustive, only then should a child be introduced to the new sources of information which books supply, and this not only because immediate cognition is of far greater value than mediate cognition, but also because the words contained in books can be rightly interpreted into