The culture of any period is a mixture of that which docilely caters to
passing whims and fancies and that which transcends these things--and
may also pass judgment on them. Whatever defers to current tastes
becomes an entertainment which achieves success immediately or not at
all, for there is no such thing as a stage-magic exhibition or a
football game which, unrecognized today, will become famous a hundred
years from now. Literature is another matter: it is created by a process
of natural selection of values, which takes place in society and which
does not necessarily relegate works to obscurity if they are also
entertainment, but which consigns them to oblivion if they are only
entertainment.
-- Stanislaw Lem. "Philip K. Dick: A Visionary Among the
Charlatans" Translated from the Polish by Robert Abernathy. Science
Fiction Studies # 5 (March 1975).
http://www.depauw.edu/sfs/backissues/5/lem5art.htm