Of human knowledge as a whole and in every branch of it, by far the
largest part exists nowhere but on paper,--I mean, in books, that
paper memory of mankind. Only a small part of it is at any given
period really active in the minds of particular persons. This is due,
in the main, to the brevity and uncertainty of life; but it also comes
from the fact that men are lazy and bent on pleasure. Every generation
attains, on its hasty passage through existence, just so much of human
knowledge as it needs, and then soon disappears. Most men of learning
are very superficial. Then follows a new generation, full of hope, but
ignorant, and with everything to learn from the beginning. It seizes,
in its turn, just so much as it can grasp or find useful on its brief
journey and then too goes its way. How badly it would fare with human
knowledge if it were not for the art of writing and printing! This it
is that makes libraries the only sure and lasting memory of the human
race, for its individual members have all of them but a very limited
and imperfect one. Hence most men of learning as are loth to have
their knowledge examined as merchants to lay bare their books.

Human knowledge extends on all sides farther than the eye can reach;
and of that which would be generally worth knowing, no one man can
possess even the thousandth part.

All branches of learning have thus been so much enlarged that he
who would "do something" has to pursue no more than one subject and
disregard all others. In his own subject he will then, it is true, be
superior to the vulgar; but in all else he will belong to it. If we
add to this that neglect of the ancient languages, which is now-a-days
on the increase and is doing away with all general education in the
humanities--for a mere smattering of Latin and Greek is of no use--we
shall come to have men of learning who outside their own subject