Fair is foul, and foul is fair;
Hover through the fog and filthy air.
Thus chant the three witches at the beginning of Shakespeare’s Macbeth. Now it’s clear enough that the witches weren’t talking about formalism; they had more sinister, bloodier business to attend to. But suppose for a moment that they were talking about formalism–in aesthetics in general, or about formalism in musicology, music theory, and composition in particular. What then might their words mean?