“If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.”
Source : John von Neumann's remarks as keynote speaker at the first national meeting of the Association for Computing Machinery (1947) as quoted in "Archaeology of computers: Reminiscences, 1945-1947" by Franz L. Alt, Communications of the ACM, Volume 15, Issue 7, special issue: Twenty-fifth anniversary of the Association for Computing Machinery (p. 694), July 1972.