crop of prejudice; for the subsequent lessons, which are learned from
real life in the world have to be devoted mainly to their extirpation.
_To unlearn the evil_ was the answer, according to Diogenes
Laertius,[1] Antisthenes gave, when he was asked what branch of
knowledge was most necessary; and we can see what he meant.

[Footnote 1: vi. 7.]

No child under the age of fifteen should receive instruction in
subjects which may possibly be the vehicle of serious error, such as
philosophy, religion, or any other branch of knowledge where it is
necessary to take large views; because wrong notions imbibed early can
seldom be rooted out, and of all the intellectual faculties, judgment
is the last to arrive at maturity. The child should give its attention
either to subjects where no error is possible at all, such as
mathematics, or to those in which there is no particular danger in
making a mistake, such as languages, natural science, history and so
on. And in general, the branches of knowledge which are to be studied
at any period of life should be such as the mind is equal to at that
period and can perfectly understand. Childhood and youth form the time
for collecting materials, for getting a special and thorough knowledge
of the individual and particular things. In those years it is too
early to form views on a large scale; and ultimate explanations must
be put off to a later date. The faculty of judgment, which cannot come
into play without mature experience, should be left to itself; and
care should be taken not to anticipate its action by inculcating
prejudice, which will paralyze it for ever.

On the other hand, the memory should be specially taxed in youth,
since it is then that it is strongest and most tenacious. But in