I know exactly what I have photographed [in his series 'Equivalents', 1925 - 1934]. I know I have done something that has never been done... I also know that there is more of the really abstract in some 'representation' than in most of the dead representations of the so-called abstract so fashionable now.

In a letter about his 'Equivalents' to Hart Crane; as quoted in Photography as High Art, Hilton Kramer, (1982-12-19)., in 'New York Times'. p. 1. Retrieved 2008-12-26; as quoted on Wikipedia.