“I consider that a
man’s brain originally is like a little empty attic, and
you have to stock it with such furniture as you choose. A fool
takes in all the lumber of every sort that he comes across, so
that the knowledge which might be useful to him gets crowded
out, or at best is jumbled up with a lot of other things, so
that he has a difficulty in laying his hands upon it. Now the
skillful workman is very careful indeed as to what he takes
into his brain-attic. He will have nothing but the tools which
may help him in doing his work, but of these he has a large
assortment, and all in the most perfect order. It is a mistake
to think that that little room has elastic walls and can
distend to any extent. Depend upon it there comes a time when
for every addition of knowledge you forget something that you
knew before. It is of the highest importance, therefore, not to
have useless facts elbowing out the useful ones.”
Sir Arthur Conan Doyle, A Study in
Scarlet