Our metaphorical system, by naming nonspatial experiences after spatial ones, imputes to sounds, smells, tastes, emotions, and thoughts qualities like the colors, luminosities, shapes, angles, textures, and motions of spatial experience. And to some extent the reverse transference occurs; for, after much talking about tones as high, low, sharp, dull, heavy, brilliant, slow, the talker finds it easy to think of some factors in spatial experience as like factors of tone. Thus we speak of "tones" of color, a gray "monotone," a "loud" necktie, a "taste" in dress: all spatial metaphor in reverse. Now European art is distinctive in the way it seeks deliberately to play with, synesthesia. Music tries to suggest scenes, color, movement, geometric design; painting and sculpture are often consciously guided by the analogies of music's rhythm; colors are conjoined with feeling for the analogy to concords and discords. The European theater and opera seek a synthesis of many arts. It may be that in this way our metaphorical language that is in some sense a confusion of thought is producing, through art, a result of far-reaching value--a deeper esthetic sense leading toward a more direct apprehension of underlying unity behind the phenomena so variously reported by our sense channels.What I don't know is whether this is something in Western culture alone. In fact, the very idea of Western culture is perhaps a mistake, especially when contrasted to anything else. So I don't that other non-Western culture don't hear musical timbres as colors, as we do, bright and dark. I don't know that other cultures don't combine visually elaborate costumes with music and dance in rituals (in fact, this is obviously false.) And I don't know why he thinks of space as such a separate category from other sensory experience so that he needs to think of this as a "reversal" when it is all part of the same process. Other than than, brilliant.
Synesthesia is probably at the root of all metaphor, and metaphor is universal.