From: Haines Brown, Central Connecticut State Univ. BROWNH@CCSUA.CTSTATEU.edu
Slightly revised. HB
I've always assumpted that the Wu and Yuezi were Tocharian, and that Tocharian-speakers survived well after the date of 2400 BC and probably until absorbed in to the Xiungnu confederation. Would someone kindly straighten me out?
As for the point about diffusionism, first, I've always considered the motives of its advocates suspect when the advocate happens to share the ethnic, linguistic, or racial identity of the originators of diffusing ideas.
Second, my understanding of "migration" is that today it is no longer felt typically to be a mass movement of peoples, but instead a "wave of cultural advance" in which the movement of a language or culture does not necessarily imply a mass organized movement of peoples (genes). The Xiungnu themselves are a classic example.
Third, my understanding of modern notions of scientific innovation (Mokyr's Lever of Riches, for example) emphasizes that innovation is a dialectical process in which a new development depends as much as outside factors as it does on internal ones; that both outside stimulus and inside adoption require equally innovative active participation. Put more usefully, I'd insist that innovation is an "emergent process" in which outcomes are constrained by initial factors, whether internal or external in origin, but are essentially novel, attributed not to the past, but primarily to the actors in an historical present.
Sorry for burdening you with this, but the implicit racism that is inevitably part of diffusionism and hopefully is contributing to its demise, raised my hackles ("hackles"? As on a fishing fly?).
Haines Brown (firstname.lastname@example.org)