Malthus introduced exponential growth rates, but not equilibria; he assumed a runaway growth would lead to collapse. Logistic functions, which describe equilibrium-finding, were introduced by Pierre Verhulst.
John von Neumann and John Nash deserve some credit for founding game theory; in particular the strategies described are minimax strategies, introduced by von Neumann.
I agree that these aren't Malthusian, and some aren't even true. The ones that are true seem to exemplify incentives and constraints. When you have an incentive to do more, you do more until either the incentive (marginal_benefit - marginal_cost) or your ability to do a little more fades to zero. When the incentives or constraints change, the behavior adapts accordingly. A Malthusian collapse is a special case that is not relevant to most situations of incentives and constraints.
But the reason that Malthus' doom-mongering hasn't come to pass is because he failed to consider that there was sufficient incentive for people to find alternatives, such that they could skirt the constraints.
Malthus said that the carrying capacity of Earth is limited to X because of finite arable land (and so on). But then humans came up with irrigation, and crop rotation, and terracing, and selective breeding, and fertilizers and insecticides, and powered machinery, etc., all of which allowed the Earth to provide for ever-increasing numbers of people.
Malthus saw humanity as limited to subsistence dirt farming, but the people saw the ability to prosper, have large families, etc., as sufficient incentive to invent alternatives. The incentives didn't change, and the constraints only changed so far as did the body of human knowledge.
> But the reason that Malthus' doom-mongering hasn't come to pass is because he failed to consider that there was sufficient incentive for people to find alternatives, such that they could skirt the constraints.
No, his doom-mongering was wrong because the alternative to collapse he laid out as improbable - 'moral restraint' - turned out to actually happen, leading to the very strange phenomenon known as the 'demographic transition'. Which we still don't understand why it happened, how long it will last, or where it will break down and how, so I don't blame Malthus.
I do blame Internet commenters facilely writing off Malthus as falsified by technology. Go actually read his essays! No, some geometric improvements in irrigation and fertilizers do not disprove him. Agriculture is not expanding exponentially: what happened was the population stopped growing as fast as it could. That is all.
the population stopped growing as fast as it could. That is all.
No. Population growth has slowed, but not stopped.
Of the 7 Billion people alive today, how many of them are not better off than virtually anyone of Malthus' day 200 years ago? How many people have no access to antibiotics, running water, and a wealth of conveniences that they take for granted? Yes, there are many people that don't have these advantages. But today, much of the world is better off than virtually anyone from 2 centuries past.
So that's not all, there must be something else.
The Simon/Ehrlich wager did not involve population statistics at all. It involved changes in the prices of commodities.
In other words, Ehrlich (the Malthus disciple) lost the bet because in real life, people find substitutes for resources for which prices are increasing. Thus quantity demanded decreases, and eventually price decreases.
Our ancestors used to hunt whales into oblivion to get (amongst other things) blubber to fuel lamps. But as the whale population decreased, so did the supply of blubber, and thus prices rose. That led to people finding alternative means of lighting, and the end is that we don't hunt whales hardly at all anymore.
Thus, the fact that greater tension between resource availability and quantity demanded lead to increased prices. That causes somebody to say to himself "if people are willing to pay so much for resource X, they'd be willing to pay just a little less to me for an alternative". He figures out how, people switch, and the market for resource X declines.
Assuming, as Malthus did, that people breed at a rate above replacement whenever they have the means to do so(which turns out not to be true these days in many countries, and may turn out not to be true for the world as a whole soon), population growth will eventually reach a rate at which the world would be a ball of humans expanding faster than the speed of light. It's hard to imagine human ingenuity figuring out a way to make that happen. Exponential growth is a bitch. HN readers should understand this, because it's the same thing that makes exponential time algorithms unreasonably slow, no matte what hardware you throw at them.
A century or two of faster than usual technological growth does not falsify Malthus, nor does a hysterical follower like Ehrlich who made predictions that were obviously ludicrous when he made them (he predicted the extinction of marine animal life by 1980 in 1970, which is not justified by anything Malthus wrote). Declining birthrates in the face of prosperity does - if it lasts.
Note that although Simon won the bet, "if you re-round the same bet on a rolling basis.. [Ehrlich] has won by such a big margin in the last decade that it has more or less undone the price gains of the previous century." (quoting Peter Thiel in a debate with George Gilder: Accelerating or Decelerating? The Prospects for Technology and Economic Growth http://youtube.com/watch?v=XRrLyckg8Nc)
> The Simon/Ehrlich wager did not involve population statistics at all. It involved changes in the prices of commodities. In other words, Ehrlich (the Malthus disciple) lost the bet because in real life, people find substitutes for resources for which prices are increasing. Thus quantity demanded decreases, and eventually price decreases.
> The argument often circles back to the bet made in 1980 between the biologist Paul Ehrlich, who foretold catastrophic scarcity caused by overpopulation, and the economist Julian Simon, who argued that any short-term increase in resource prices caused by population growth will stimulate inventors and entrepreneurs to find new ways to exploit those resources, lowering prices in the long run. The two men picked five commodities and wagered on whether their prices, taken as an indicator of scarcity, would be higher or lower in 1990. Simon won, 5-0, even though the world’s population grew by 800 million during that decade.
>
>Malthusians have been trying to live down that defeat ever since, but, as Grantham points out in his July letter, if we extend the original bet past its arbitrary 10-year limit to the present day, Ehrlich wins the five-commodity bet 4-1, and he wins big if the bet is further extended to all important commodities. Grantham concludes that the longer-run story of the bet “proves, in fact, both that man is mortal and must make short-term bets, and, more importantly, that Ehrlich’s argument was right (so far).” That final parenthesis, a nod to uncertainty, leaves open the remote possibility that the apparent paradigm shift might still turn out to be just a bubble in commodity prices.
Or
> An equally weighted portfolio of the five commodities is now higher in real terms than the average of their prices back in 1980 (see chart).
>
> The Cornucopians might argue that today’s metals prices are due to the buoyancy of demand in the developing world rather than any cataclysmic shortages in supply. But the Malthusians might retort that man’s famed ingenuity has not stopped prices from rising in real terms over an extended period. Place your bets.
It is true, though, that there is a limit to how much people this planet can reasonably
sustain, and I'd say we're billions over that mark - the only reason the system still
works (barely) is because a large part of the world's population lives in poverty and
hunger.
Optimization will only get you so far. We simply can't optimize away the fact that there
is limited space on this planet and that we're pretty much out of it already. We can't
sustain 7 billion people, tendency growing. Not at a humane average living standard.
I don't think you deserve the downvotes; your point may be valid, even if pessimistic. Just because we've managed to overcome what seemed to be infeasible hurdles doesn't mean we will continue to do so. Of course, just because the new hurdles seem even less feasible doesn't mean we won't overcome them, either. The point being that you'll never know you're at the cusp until you're well into the valley on the other side.
Malthus was wrong about the long-run behavior of populations, but I think it's worthwhile to note that we can feed yesterday's population today. World hunger could have been a solved problem with all the advances that were made. But who has the right to tell you not to breed?
Well, the argument needed to be made because there are so many who subscribe to it.
But the important point that this misses is that the availability of any given resource isn't what's critical, since all throughout history it's been shown that human ingenuity has been able to find alternatives.
The critical factor is that human ingenuity. And because that human factor -- the availability of someone who can figure out that alternative, and who has the incentive to do so -- is growing with the growth of the population, are horizons are only broadening!
Contrary to Malthus, an increasing population is, in the long run, better for mankind's prospects.
I'm not at all sure the last part is true. It's difficult to do experiments in history, of course, but there are historical examples of quite fast-advancing societies with smallish, stable populations, and of not-making-progress societies with large and growing populations. Enough that I doubt any general causal relationship between population growth and technological advances or quality of life.
And the biggest growth is in places where it is least sustainable. However, as far as I understand hunger is not a problem of the quantity of the food, it is a problem of distribution.
I do hold somehow cynical view, that the bigger percentage of humanitarian aid should be in form of condoms, not food.
http://en.wikipedia.org/wiki/Pierre_Fran%C3%A7ois_Verhulst
John von Neumann and John Nash deserve some credit for founding game theory; in particular the strategies described are minimax strategies, introduced by von Neumann.
http://en.wikipedia.org/wiki/Minimax