§ 9. Next in order of importance, according to Mr. Spencer, comes the knowledge which aids indirect self-preservation by facilitating the gaining of a livelihood. Here Mr. Spencer thinks it necessary to prove to us that such sciences as mathematics and physics and biology underlie all the practical arts and business of life. No one would think of joining issue with him on this point; but the question still remains, what influence should this have on education? “Teach science,” says Mr. Spencer. “A grounding in science is of great importance, both because it prepares for all this [business of life], and because rational knowledge has an immense superiority over empirical knowledge.” Should we teach all sciences to everybody? This is clearly impossible. Should we, then, decide for each child what is to be his particular means of money-getting, and instruct him in those sciences which will be most useful in that business or profession? In other words, should we have a separate school for each calling? The only attempt of this kind which has been made is, I believe, the institution of _Handelschulen_ (commercial schools) in Germany. In them, youths of fifteen or sixteen enter for a course of two or three years’ instruction which aims exclusively at fitting them for commerce. But, in this case, their general education is already finished. With us, the lad commonly goes to work at the business itself quite as soon as he has the faculties for learning the sciences connected with it. If the school sends him to it with a love of knowledge, and with a mind well disciplined to acquire knowledge, this will be of more value to him than any special information.