rangement as this would employ the youthful power of the memory to
best advantage, and supply excellent working material to the faculty
of judgment, when it made its appearance later on.

A man's knowledge may be said to be mature, in other words, it has
reached the most complete state of perfection to which he, as an
individual, is capable of bringing it, when an exact correspondence is
established between the whole of his abstract ideas and the things he
has actually perceived for himself. This will mean that each of
his abstract ideas rests, directly or indirectly, upon a basis of
observation, which alone endows it with any real value; and also
that he is able to place every observation he makes under the right
abstract idea which belongs to it. Maturity is the work of experience
alone; and therefore it requires time. The knowledge we derive from
our own observation is usually distinct from that which we acquire
through the medium of abstract ideas; the one coming to us in the
natural way, the other by what people tell us, and the course of
instruction we receive, whether it is good or bad. The result is, that
in youth there is generally very little agreement or correspondence
between our abstract ideas, which are merely phrases in the mind, and
that real knowledge which we have obtained by our own observation. It
is only later on that a gradual approach takes place between these two
kinds of knowledge, accompanied by a mutual correction of error; and
knowledge is not mature until this coalition is accomplished. This
maturity or perfection of knowledge is something quite independent of
another kind of perfection, which may be of a high or a low order--the
perfection, I mean, to which a man may bring his own individual
faculties; which is measured, not by any correspondence between the
two kinds of knowledge, but by the degree of intensity which each kind
attains.

For the practical man the most needful thing is to acquire an accurate
and profound knowledge of _the ways of the world_. But this, though
the most needful, is also the most wearisome of all studies, as a man
may reach a great age without coming to the end of his task; whereas,
in the domain of the sciences, he masters the more important facts
when he is still young. In acquiring that knowledge of the world, it
is while he is a novice, namely, in boyhood and in youth, that the
first and hardest lessons are put before him; but it often happens
that even in