I think that in referring to "tribes" we are mixing a number of things here - nation states, ethnicities, ideologies, religious beliefs, etc. There are probably no "tribes" left anywhere on earth.
Ed Keith Hudson > We can even find examples of this "anomalous" behaviour in modern times -- > even extreme examples when the tribes are simultaneously at war! In the > recent conflicts in Bosnia, Serbs and Muslims who would be inflicting the > most savage cruelties on each other, would also be trading with each other > in the streets on the next day. For the first 12 months or so of WWII, the > British were supplying armaments, chemicals, and even battledress cloth to > the Germans! (In the latter case, the company bosses knew it (of course), > the governments knew it, and the workforces concerned knew it -- but it > continued for a considerable time before convenient intermediate ports were > no longer neutral.) > > In other words, the ability to trade is also a very strong force in human > behaviour.
