BRAIN, n. An apparatus with which we think what we think.

BRAIN, n. An apparatus with which we think what we think. That which
distinguishes the man who is content to _be_ something from the man
who wishes to _do_ something. A man of great wealth, or one who has
been pitchforked into high station, has commonly such a headful of
brain that his neighbors cannot keep their hats on. In our
civilization, and under our republican form of government, brain is so
highly honored that it is rewarded by exemption from the cares of
office.
-- Ambrose Bierce, "The Devil's Dictionary"