Art in its most primitive state is a simple imitation of nature. But it quickly becomes imitation of nature in the wider sense of this idea, that is, not merely imitation of outer but also of inner nature. In other words, art does not then represent merely the objects or the occasions that make impressions, but above all these impressions themselves, ultimately without reference to their What, When, and How. Inference of the original, external object is here perhaps of only secondary importance due to its lack of immediacy. In its most advanced state, art is exclusively concerned with the representation of inner nature. Here its aim is just the imitation of impressions, which have now combined, through association with one another and with other sense impressions, to form new complexes and new motives, new stimulil. At this state, inference of the external stimulus is almost certain to be inadequate. At all stages the imitation of the model, of the impression, or of the complex of impressions is only relatively faithful. This is true, on the one hand, because of the limits of out abilities; on the other, because, whether we are conscious of it or not, the material [the medium] in which the imitation is presented differs from the material or materials of the stimulus, so that, for example, visual or tactile sensations might be represented in the material of auditory sensations.
–Arnold Schoenberg, Theory of Harmony, p. 18
Wow. If there’s one thing that never fails to satisfy me in the extreme, it’s the succinct, concise technical writing of an expert. To read someone summarize an activity into which I endlessly pour myself is as mystifying as it is illuminating.