 Dumber brahmins and merchants will have no children at all and die out Do you have a cite for that? I don't know a thing about the current reproductive structure in India, but this was a question about the past. I don't know what Brahmins did to earn a living in the past, or if success translated into increased number of children. It is not immediately obvious that religious occupations demand tremendous intelligence, or if intelligence, or that religious occupations have high IQ elasticity. 