Art must unquestionably have a social value; that is, as a potential means of communication it must be addressed, and in comprehensible terms, to the understanding of mankind.

Rockwell Kent

Workers of the World Unite, 1937

Rockwell Kent (June 21, 1882–March 13, 1971) was an American painter, printmaker, illustrator, and writer.

http://en.wikipedia.org/wiki/Rockwell_Kent