premise: They live similar lives, conduct similar courses, and with similar subventions go to similar conferences and give similar papers on every continent (much as David Lodge describes them in Small World ).  They are not as tightly knit as other fraternities, past and present (Knights Templar, Freemasons, Jesuits, Mafia, Ancient and Mystical Order of the Rosy Cross, corporate executives of Coca-Cola or Chrysler, or managers of labor unions).
hypothesis: Each member is wildly different and they share little in common.