Slippery

In the European classical tradition, the piano, with its twelve precise divisions of the octave—inflexible, immovable—has dictated musical thinking for several centuries. Once developed, the piano quickly became a machine of almost tyrannical influence throughout the Western world. Its division of the octave into twelve intervals, each mathematically equidistant from its neighbors, forces one to regard pitches as discrete entities, like nations with strictly policed [borders]. A piano-generated melody goes from point to point with no expressive sliding in between. This is not a fault—Bach and Mozart built their entire work on the notion—rather, it is a stylistic choice. Since the advent of the black-and-white keyboard… Western instrumental music has had to state itself according to the twelve discrete, individual pitches of the scale, resulting in a more limited universe of emotional expression.

—John Adams, Hallelujah Junction, ch. 10, “The Machine in the Garden”