Preindustrial living standards are predictable based on knowledge of disease and environment. Differences in social energy across societies were muted by the Malthusian constraints. They had minimal impacts on living conditions. Since the Industrial Revolution, however, we have entered a strange new world in which economic theory is of little use in understanding differences in income across societies, or the future income in any specific society. Wealth and poverty are a matter of differences in local social interactions that are magnified, not dampened, by the economic system, to produce feast or famine.

Every socialist wishes to revolutionize society from the economic angle and all the blessings he expects are to come through a change in economic institutions. This of course implies a theory about social causation—the theory that the economic pattern is the really operative element in the sum total of the phenomena that we call society.