Thought I saw the idea above, but kinda like trying to define pornography. When the US Spreme Court was asked to do so, the best the supposedly best nine legal/jurisprudential minds in the country could do for guidance is "you know it when you see it." (That and some nonsensical, community-based, idiosyncratic, sliding, festooned, subjective drivel).
And I always thought the Armstrong quote (or, another one, at any rate) was, in response to the question by a reporter what is jazz, "honey, if you gotta ask, you'll never understand."