Goodman (1968, 1977, 1978) contributed basic theory about symbol systems that had an influence on semiotics
(Salomon, 1979a) and also added a cognitive (as contrasted to an aesthetic) dimension to the interpretation of art. In his
“theory of symbols,” he created a taxonomy of the major symbol systems used by human beings, including gestural
and visual graphics systems. The theoretical literature on semiotics and symbol systems is rich. The research to validate
the theories is, as yet, not so rich.