"Perception, then, emerges as that relatively primitive, partly autonomous, institutionalized, ratiomorphic subsystem of cognition which achieves prompt and richly detailed orientation habitually concerning the vitally relevant, mostly distal aspects of the environment on the basis of mutually vicarious, relatively restricted and stereotyped, insufficient evidence in uncertainty-geared interaction and compromise, seemingly following the highest probability for smallness of error at the expense of the highest frequency of precision."
-- From "Perception and the Representative Design of Psychological Experiments,"
by Egon Brunswik.

"That's a simplification. Perception is standing on the sidewalk, watching all the girls go by."
-- From "The New Yorker," December 19, 1959.

From "Principles of Neurodynamics: Perceptrons and the Theory of Brain Mechanisms", by Frank Rosenblatt, 1962.