Americans of recent generations will remember a game on the children's television show Sesame Street called “One of these things is not like the others,” which teaches young children to balance similarities and differences by establishing categories. Most people today would have no problem playing that game with these three tunes:

1. the Scottish fiddle dance tune “John Anderson My Jo,” probably derived from a bawdy song;

2. “MacLeod's Rowing,” a Piobaireachd (“pibroch”) for Highland bagpipe;

3. Jean-Baptiste Lully's air “Sommes-nous pas trop heureux” from the ballet L'Impatience (1661).

The last here certainly seems the odd one out. It is French and the other two are Scottish. More importantly, by today's usual reckoning standards, it is “classical”: part of a well-funded world of urban, sophisticated music-making – and part of a literate tradition in which authorship is clearly established, and pieces are communicated as fixed texts reflecting that author's apparent intentions. The other two tunes, meanwhile, are apparently varieties of “folk” or “traditional” music: part of a communal tradition, usually disseminated anonymously through oral communication, and thus undergoing constant minor variations and additions.

Facile categorizations such as those encouraged by the Sesame Street game are always problematic on closer view of course, and “folk” and “classical” are among the most problematic of all. For example, one could easily argue, as many writers now do, that the pibroch is a form of classical music.