From Maya Deren:

(All of this goes for photography as well, I think).

Nothing can be achieved in the art of film until its form is
  understood to be the product of a completely unique complex:
  the exercise of an instrument which can function,
  simultaneously, both in terms of discovery and invention.

 This dialectical complex, in turn, provides the emotional tension which propels any given work. To lean too heavily to one side or the other of this polarity is to take an easy way out and risk aesthetic impoverishment. Rather, the contradictory nature of cinema should be wholly embraced. Out of greater difficulty comes a potential for greater reward:

  This very profusion of potentialities seems to create
  confusion in the minds of most film-makers, a confusion which
  is diminished by eliminating a major portion of those
  potentialities in favor of one or two, upon which the film is
  subsequently structured. An artist, however, should not seek
  security in a tidy mastery over the simplifications of
  deliberate poverty; he should instead have the creative
  courage to face the danger of being overwhelmed by fecundity
  in the effort to resolve it into simplicity and economy.