We all listen to music according to our separate capacities. But, for the sake of analysis, the whole listening process may become clearer if we break it up into its component parts, so to speak. In a certain sense we all listen to music on three separate planes. For lack of a better terminology, one might name these: (1) the sensuous plane, (2) the expressive plane, (3) the sheerly musical plane. The only advantage to be gained from mechanically splitting up the listening process into these hypothetical planes is the clearer view to be had of the way in which we listen.
Source: Aaron Copland: A Reader (NY: Routledge, 2004): 3-7
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