Mathematics, trigonometry, chemistry, psychoanalysis, music, and what not have been related to cubism to give it an easier interpretation. All this has been pure literature, not to say nonsense, which brought bad results, blinding people with theories. Cubism has kept itself within the limits and limitations of painting, never pretending to go beyond it.

As quoted by Marius de Zayas, in 'The Arts', New York, May 1923 - "Picasso Speaks," 1923