Like all Marxists, these two are obliged to follow their masters voice. Capital, vol. 3, chapter 47: “ The possibility is here presented for definite economic development taking place, depending, of course, upon favourable circumstances, inborn racial characteristics, etc...” Engels: (Marx and Engels, Selected Works, Vol. 3, p. 502.): “We regard economic conditions as the factor which ultimately determines historical development. But race is itself an economic factor ... ”.