" The almost universal desire of people to trade with one another, not for
the selfless benefit of others or the society, but for the selfish benefit of
one’s own kin and kind; it is an unintended consequence that trade
establishes trust between strangers and lowers between-group enmity,
as well as produces greater wealth for both trading partners and groups. "

― Michael Shermer , Brain, Belief, and Politics (Cato Unbound Book 92011)