While the second classification of complexity and contradiction
in architecture relates to form and content as
manifestations of program and structure, the first concerns
the medium and refers to a paradox inherent in perception
and the very process of meaning in art: the complexity and
contradiction that results from the juxtaposition of what an
image is and what it seems. Joseph Albers calls "the discrepancy
between physical fact and psychic effect" a contradiction
which is "the origin of art." And, indeed, complexity
of meaning, with its resultant ambiguity and tension,
has been characteristic of painting and amply recognized in
art criticism. Abstract Expressionism acknowledges perceptual
ambiguity, and the basis of Optical Art is shifting
juxtapositions and ambiguous dualities relating to form and
expression. Pop painters, too, have employed ambiguity to
create paradoxical content as well as to exploit perceptual
possibilities.