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Malthus didn't account for technology. We'll see how far that stretches.

Malthus reasoning is rock solid. Exponential population growth puts strain on finite resources. Malthus was a huge influence on Darwin. That premise - the tension between different growth rates of populations and resources - underlies the theory of natural selection, people on this forum will certainly get behind that. But call it Malthusian, and it's suddenly false.

It's also wrong to think that Malthus only just predicted doom. He used his model to explain a great deal of sociological phenomena (e.g. infanticide in china, delayed child rearing in wealthier societies, differences in diet between east and west).

It's not that Malthus was wrong. It was that he was only mostly correct. People today are nitpicking on the little bits and pieces where he was incomplete. He also wrote this at the start of the industrial revolution. He couldn't have known.



> Malthus didn't account for technology. We'll see how far that stretches.

The later you are in the exponential, the less technology can stretch it.

At a 1% annual growth rate, for example, we've about 3400 years before the mass needed for the bodies of all then living humans will equal the combined mass of the Earth and Moon.

Another 600 years and the mass of living humans equals the mass of Jupiter.

700 more years and the mass of all living humans equals the mass of the entire solar system.

2000 more years the mass of all living humans equals the mass of the entire Milky Way.

Less than 100 years after that we need to add the entire mass of the Andromeda Galaxy.

From that to needing the entire mass of the observable universe for human bodies is just another 5500 years (around 12300 years from now).

Coincidentally (at least I think it is a coincidence...) that's also about the time that without FTL travel we run out of space in the universe to hold everybody. Right now every human is on or very near Earth. Given no FTL, it follows that N years from now every human must be within N light-years of Earth.

Take the volume of a sphere of radius N light-years, and divide that by the number of people alive N years from now at 1% annual growth. That gives you how much space you have available per person.

Around N=12000 the available space per person to drops under 0.06 m^3, which is the volume of a typical human.

At 0.1% growth all the intervals above are about 10 times longer, so we hit the mass limit and the space limit at around 120000 years from now. 0.01% growth moves those both out to around 1.2 million years.

Exponentials are truly terrifying. They can be cute and cuddly when they are young, but the mature form eats everything.


Yikes. These numbers are mindblowing ...

I forget where I read this:

"Exponentials often end up being sigmoids in disguise."


Technology is a pretty big miss.

Interesting to note that a lot of ideas contemporary with Malthus were wrong. For example, it was thought that the popular use of contraception would result in people marrying younger, since men would not fear taking a wife early in their career (they could control when and how many children to have, in harmony with whatever economic resources they might have). It turns out that contraception had the opposite effect




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