Tag Archives: Limits

The model that ate Europe

arXiv covers modeling on an epic scale in Europe’s Plan to Simulate the Entire Earth: a billion dollar plan to build a huge infrastructure for global multiagent models. The core is a massive exaflop “Living Earth Simulator” – essentially the socioeconomic version of the Earth Simulator.


I admire the audacity of this proposal, and there are many good ideas captured in one place:

  • The goal is to take on emergent phenomena like financial crises (getting away from the paradigm of incremental optimization of stable systems).
  • It embraces uncertainty and robustness through scenario analysis and Monte Carlo simulation.
  • It mixes modeling with data mining and visualization.
  • The general emphasis is on networks and multiagent simulations.

I have no doubt that there might be many interesting spinoffs from such a project. However, I suspect that the core goal of creating a realistic global model will be an epic failure, for three reasons. Continue reading

Faking fitness

Geoffrey Miller wonders why we haven’t met aliens. I think his proposed answer has a lot to do with the state of the world and why it’s hard to sell good modeling.

I don’t know why this 2006 Seed article bubbled to the top of my reader, but here’s an excerpt:

The story goes like this: Sometime in the 1940s, Enrico Fermi was talking about the possibility of extraterrestrial intelligence with some other physicists. … Fermi listened patiently, then asked, simply, “So, where is everybody?” That is, if extraterrestrial intelligence is common, why haven’t we met any bright aliens yet? This conundrum became known as Fermi’s Paradox.

It looks, then, as if we can answer Fermi in two ways. Perhaps our current science over-estimates the likelihood of extraterrestrial intelligence evolving. Or, perhaps evolved technical intelligence has some deep tendency to be self-limiting, even self-exterminating. …


The fundamental problem is that an evolved mind must pay attention to indirect cues of biological fitness, rather than tracking fitness itself. This was a key insight of evolutionary psychology in the early 1990s; although evolution favors brains that tend to maximize fitness (as measured by numbers of great-grandkids), no brain has capacity enough to do so under every possible circumstance. … As a result, brains must evolve short-cuts: fitness-promoting tricks, cons, recipes and heuristics that work, on average, under ancestrally normal conditions.

The result is that we don’t seek reproductive success directly; we seek tasty foods that have tended to promote survival, and luscious mates who have tended to produce bright, healthy babies. … Technology is fairly good at controlling external reality to promote real biological fitness, but it’s even better at delivering fake fitness—subjective cues of survival and reproduction without the real-world effects.


… I suspect that a certain period of fitness-faking narcissism is inevitable after any intelligent life evolves. This is the Great Temptation for any technological species—to shape their subjective reality to provide the cues of survival and reproductive success without the substance. Most bright alien species probably go extinct gradually, allocating more time and resources to their pleasures, and less to their children. They eventually die out when the game behind all games—the Game of Life—says “Game Over; you are out of lives and you forgot to reproduce.”

I think the shorter version might be,

The secret of life is honesty and fair dealing… if you can fake that, you’ve got it made. – Attributed to Groucho Marx

The general problem for corporations and countries is that there’s a big problem attributing success to individuals. People rise in power, prestige and wealth by creating the impression of fitness, rather than creating any actual fitness, as long as there are large stocks that separate action and result in time and space and causality remains unclear. That means that there are two paths to oblivion. Miller’s descent into a self-referential virtual reality could be one. More likely, I think, is sinking into a self-deluded reality that erodes key resource stocks, until catastrophe follows – nukes optional.

The antidote for the attribution problem is good predictive modeling. The trouble is, the truth isn’t selling very well. I suspect that’s partly because we have less of it than we typically think. More importantly, though, leaders who succeeded on BS and propaganda are threatened by real predictive power. The ultimate challenge for humanity, then, is to figure out how to make insight about complex systems evolutionarily successful.

Maya fall to positive feedback

NASA has an interesting article on the fall of the Maya. NASA-sponsored authors used climate models to simulate the effects of deforestation on local conditions. The result: evidence for a positive feedback cycle of lower yields, requiring greater deforestation to increase cultivated area, causing drought and increased temperatures, further lowering yields.

Mayan vicious cycle







An SD Conference article by Tom Forest fills in some of the blanks on the other problems:

… this paper illustrates how humans can politically intensify resource shortages into universal disaster.

In the current model, the land sector has two variables. One is productivity, which is exhausted by people but regenerates over a period of time. The other… is Available Land. When population exceeds carrying capacity, warfare frequency and intensity increase enough to depopulate land. In the archaeological record this is reflected by the construction of walls around cities and the abandonment of farmlands outside the walls. Some land becomes unsafe to use because of conflict, which then reduces the carrying capacity and intensifies warfare. This is an archetypal death spiral. Land is eventually reoccupied, but more slowly than the abandonment. A population collapse eventually hastens the recovery of productivity, so after the brief but severe collapse growth resumes from a much lower level.

The key dynamic is that people do not account for the future impact of their numbers on productivity, and therefore production, when they have children. Nor does death by malnutrition and starvation have an immediate effect. This leads to an overshoot, as in the Limits to Growth, but the policy response is warfare proportionate to the shortfall, which takes more land out of production and worsens the shortfall.

Put another way, in the growth phase people are in a positive-sum game. There is more to go around, more wealth to share, and population increase is unhindered by policy or production. But once the limits are reached, people are in a zero-sum game, or even slightly negative-sum. Rather than share the pain, people turn on each other to increase their personal share of a shrinking pie at the expense of others. The unintended consequence-the fatal irony-is that by doing so, the pie shrinks much faster than it would otherwise. Apocalypse is the result.

Making climate endogenous in Forest’s model would add another positive feedback loop, deepening the trap for a civilization that crosses the line from resource abundance to scarcity and degradation.

Another Look at Limits to Growth


Industrial output in Limits to Growth runs vs. history


The Growth Bubble


Letâ€™s today step out of the normal boundaries of analysis of our economic crisis and ask a radical question: What if the crisis of 2008 represents something much more fundamental than a deep recession? What if itâ€™s telling us that the whole growth model we created over the last 50 years is simply unsustainable economically and ecologically and that 2008 was when we hit the wall â€” when Mother Nature and the market both said: â€œNo more.â€


There’s plenty of speculation about the problem ahead of time:
Google news timeline - housing bubble

Google news timeline – housing bubble


Sound familiar so far?




On Limits to Growth





