Malthus vs. Malthusian Population Scares

This post is by Adam Martin, a post-doctoral fellow at DRI. The laws of economics are more powerful than the laws of physics. I once saw Deirdre McCloskey illustrate this by placing a $100 bill on the table. The laws of physics, she reminded the class, dictate that an object at rest tends to stay at rest. Economics tells us that errant $100 bills laying out in the open do not remain unattended for long. She assured the students that, were she to leave the room for several hours, economics would better predict Mr. Franklin's fate.

But how do the laws of economics fare against a tougher opponent: the laws of sexual attraction? Against them, economists--especially those march under the Malthusian banner--have been willing to cede more ground. Everyone knows, after all, that Malthus judged the "passions between the sexes" as both universal and powerful. Everyone knows that this passion leads to "geometrical" increases in population that inexorably outpace "arithmetical" increases in food. Everyone knows this is why economics is called the "dismal science." But what everyone "knows" is dead wrong.

This is not another argument about how ol' Tom-Bob got it all wrong. No, the problem with Malthus--a problem for both his self-proclaimed friends and foes--is that he we wasn't a Malthusian. Ross Emmett offers a detailed and trenchant analysis. Malthus was not arguing in a vacuum. He was responding to William Godwin's proposal to overthrow basic social institutions like private property and the family.  In a free love-fest where no one is responsible for the offspring resultant from their passions, Malthus argued, population growth would run amok. If individuals don't bear the cost of procreation, they will procreate too much. If they do bear costs of offspring, "preventative checks" such as birth control and delayed marriage will make population self-regulating. In his own words:  "Impelled to the increase of his species by an equally powerful instinct, reason interrupts his career, and asks him whether he may not bring beings into the world, for whom he cannot provide the means of subsistence." (An Essay on the Principle of Population, Chapter II). Reproductive choices respond to incentives. The laws of economics are more powerful than the laws of attraction.

Note that Malthus does not say that the incentives for procreation are automatically aligned with the common interest. If individuals do not bear the full costs of their offspring, such as any effects of Junior on the environment, they may make irresponsible decisions. But parents are no more socially responsible if they fail to account for the benefits their children will generate for others (such as new ideas on technology). What matters is that, when discussing population, we do not forget the basic lessons of economics. A top-down perspective on population that treats individuals like mindless lemmings will panic: "Unless we reduce the human population humanely through family planning, nature will do it for us through violence, epidemics or starvation."

Malthus gets right what both his followers and his more technocratic critics get wrong: the institutions within which individuals make reproductive decisions matter. The way to increase GDP per capita is not to cut the denominator. And while today’s scare tactics (Mali is “really in for a Malthusian disaster,”) and recommendations to stop having babies are not as monstrous as those of yesteryear, we should be wary of those who would intrude on one of the most personal and sacred choices individuals confront – whether to have a child. Nor is population sustainability a mere horse race between libido and technology. Consistent with the approach of classical economists, Malthus treats human nature as constant. Different institutions drive differences in fertility outcomes. In this we should all be Malthusians.