The greatest event in human history was the jump from a Malthusian economy to the modern world, starting in Europe around 1800. But what caused it? By Benjamin Friedman.

In A Farewell to Alms [2009], Gregory Clark, an economic historian at the University of California, Davis, suggests an intriguing, even startling answer: natural selection.

Focusing on England, where the Industrial Revolution began, Clark argues that persistently different rates of childbearing and survival, across differently situated families, changed human nature in ways that finally allowed human beings to escape from the Malthusian trap in which they had been locked since the dawn of settled agriculture, 10,000 years before.

Specifically, the families that propagated themselves were the rich, while those that died out were the poor. Over time, the “survival of the richest” propagated within the population the traits that had allowed these people to be more economically successful in the first place: rational thought, frugality, a capacity for hard work — in short the familiar list of Calvinist, bourgeois virtues. The greater prevalence of those traits in turn made possible the Industrial Revolution and all that it has brought. …

The heart of Clark’s analysis consists of a detailed examination of births, deaths, income and wealth in England between 1250 and 1800, as evidenced primarily by wills. Although the records are scant, he finds that on average richer people were more likely to marry than poorer people, they married at earlier ages, they lived longer once they were married, they bore more children per year of marriage, and their children were more likely to survive and to bear children themselves. The result was centuries of downward mobility, in which the offspring of richer families continually moved into the lower rungs of society. Along the way, their behavioral traits and attitudes became ever more dominant.

Clark’s hypothesis is interesting for at least two reasons. First, it provides an internal mechanism to explain the Industrial Revolution. No deus ex machina, like James Watt’s improving the steam engine, or the Whigs’ overthrow of James II leading to England’s Glorious Revolution, is necessary. Given the conditions at work in England nearly a millennium ago, changes naturally occurred that made an industrial revolution probable, if not inevitable.

Second, Darwinian evolution is usually seen as a process that works over very long periods of time, with consequences for humans that we can observe only by looking far into the past. By contrast, Clark’s explanation for the Industrial Revolution is a change in “our very nature — our desires, our aspirations, our interactions” — that occurred within recorded history, indeed within the last half-dozen centuries.

And it can be undone on a similar timescale. Current social policies encourage smarter women to have careers rather than kids.

If the traits to which Clark assigns primary importance in bringing about the Industrial Revolution are acquired traits, rather than inherited ones, there are many non-Darwinian mechanisms by which a society can impart them, ranging from schools and churches to legal institutions and informal social practices. But if the traits on which his story hinges are genetic, his account of differential childbearing and survival is necessarily central. …

People today suffer from obesity. We’ve forgotten that the main problem for people before 1800 was getting enough to eat.

Clark is thorough in explaining the perverse mechanics of the Malthusian world, in which food production and therefore population are strictly limited, together with the perverse implications that follow. (Catastrophes like the Black Death or failed harvests make people — those who survived, that is — better off by reducing the numbers competing for limited resources; improvements like sanitation or new medicines, or even charity, make everyone miserable.)

Will mankind continue to progress, or fall back into a Malthusian trap? Idiocracy or Star Trek?