Population Wars: Adam Martin replies to Global Population Speak Out

by Adam Martin I appreciate the thoughtful GPSO reply to my blog post. But I respectfully decline the offer to sign their pledge. Here is why:

Projections of population into the future that fail to account for the power of changing incentives are intellectually sterile explanations and policies that deny the rational response of individuals to incentives will prove impotent or worse.

Why are market-oriented economists so confident that population will be self-regulating? Well, under a regime of property rights, as we use up any scarce global resources, they will become relatively more scarce. This will put upward pressure on their prices. The first response is for individuals to cut back their consumption, but that's not the most important adjustment (that's only short term, after all).

The more important response is the one Julian Simon pointed out: the increase in resource prices creates an incentive to find more efficient means to use them or to come up with substitutes. Innovation of what we use and how we use it is the best path we know of to sustainability in development. Institutions such as property rights, the family, and, yes, even money are preconditions for aligning incentives with conservation and unleashing systematic resource-saving innovations.

Here both our deepest moral commitments, as well as sound economics, overlap with the professed beliefs of GPSO: certainly women should not have reproductive decisions forced upon them. So the message is not that nothing can go wrong. Absent secure individual rights, individual responsibility, and free markets, quite a bit can: first and foremost for the victims of injustice. However, simply admitting that these problems are real is a long way from endorsing statements like this (from the email I was sent):

the current size and growth of human population [is] a sustainability issue no less crucial than over-consumption in developed nations and all the resultant emissions, habitat loss and toxic pollutants. [emphasis in original]

I want to raise two problems with these sorts of statements. First, admitting that population growth can have adverse consequences is a long way from admitting that anyone has the knowledge to determine the "right" population size, even roughly. Statements like the one above, not to mention the affiliations of some of GPSO's signees--convince me that they believe otherwise. And I'm not arguing that sustainable population size is a difficult calculation to make, I'm arguing that it's meaningless. Sustainability means a balance between what present and future individuals want to do and can do. When human capacities and desires are by their nature heterogenous and changing over time--as in the long run that sustainabilitistas worry about--then what counts as sustainable is simply not knowable unless one knows current and future capacities and desires.

Second, I want to raise the question as to whether a "public discussion addressing the size and growth of human population" is compatible with those individual rights. If governments decide what the right population size is, and the actions of free and responsible individuals give rise to a different population size, either the population target or individual rights must be sacrificed. I believe--I hope--that the GPSO signees would abandon their plan. History has shown too many willing to do the opposite. It is for this reason that, while I obviously do not believe women should be coerced, I cannot sign onto "population justice" as defined by GPSO.

If it is excessive procreation we are worried about, we would do well to remember the words of Henry Simon: "Academic economics is primarily useful, both to the student and to the political leader, as a prophylactic against popular fallacies."

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.