The relative meaning of two physical facts in an emotionally controlled relation always creates the phenomenon of a third fact of a higher order, just as two musical sounds, heard simultaneously create the phenomenon of a third, fourth or fifth. The nature of this higher third is non-physical. In a sense it is magic. Each such phenomenon always overshadows the material qualities and the limited meaning of the basic factors from which it has sprung. For this reason Art expresses the highest quality of the spirit when it is surreal in nature; or, in terms of the visual arts, when it is of a surreal plastic nature.

'Search for the Real in the Visual Arts', p. 41 - Search for the Real and Other Essays (1948)