Today's Question

Potter Stewart, late Supreme Court Justice, and native of Jackson, Michigan, in his opinion on the 1964 obscenity case Jacobellis v. Ohio, stated that he could not define hard-core pornography, but knew it when he saw it.  Many intangible things in life could be defined so nebulously without much contention, but what do these things really mean, and what comprises their essences?  With that in mind, what is music?  Is anything music?  Are jack hammers and heart beats percussion?  Are humming power lines in the key of D rhythmic?  Are a group of  bull finches whistling their mating call a polyphonic lead?  How do you define music?