THERE HAVE BEEN long-standing troubles with the ways in which we categorize artists. Folk, outsider, visionary, self-taught, naive, grassroots: These words, by turns deployed, debated, rejected, and qualified, are weighed down by so much more than they delimit. Since the advent of modernism, such labels have been attached to various American artists who did not emerge via fine-art institutional pedigrees, and to diverse forms of artmaking that have been deemed peripheral to the prevailing aesthetics trafficked by the decidedly metropolitan, market-dominated centers of the self-proclaimed “art