Demographic "doomsday" misses the mark

To use your analogy: let's rather not get too complacent about figuring out the world isn't flat and risk placing all future bets on it being round.

There seem to be real concerns about whether the environment on Earth can sustain the impact of human society in its current form, and the population is an obvious lever to scale that impact.

I guess what's "surprising" is that birth rates are responding to the pressures I'm alluding to? Rather than just continuing runaway exponential expansion?

There is no underpopulation hysteria. However, the math around demographics is settled.

My peers who are skipping kids are mostly doing so because their other ambitions don't align with raising a family, which I totally get. It's a huge trade off, I hope it'll be worth it.

They do talk about whether the earth can sustain that population as a reason not to have children. They are correct to. Their children might be the generation who have to explain to their children what fish tasted like.

They often list overpopulation as a reason. But yes, it's not the only reason they give.

As an antidote to this kind of mindless negativity, just consider whether any individual human is happy to have been born. It seems very clear to me that most people enjoy being alive and so having children is moral on utilitarian grounds.

Additionally, it is reasonable in the 1790s to assume exponential population growth. It would not be until the 1830s that Verhulst would even model it as a logistic curve. Moreover, human population growth really was on a roughly exponential trajectory until very recently.

Obviously we did not experience such catastrophe. But it's also a bit wrong to call it "invalid" when it was a completely logical conclusion to make. If we're going to allow him to invent a magical technology that addresses it in 1798, then all reason goes out the window.

That's a bit unfair to Malthus though; sure it was the enlightenment, but all he could rationally go on was to assume that the last 2000 or so years of civilization would be similar to the next, in terms of food and population growth.

What would be abstract would be to make the assumption that unprecedented technological advancement would be made in the next hundred years, bordering on ( to what Malthus would be) magic. You can assume any problem will be solved if you also assume a technology will be invented to fix it. But that's not a reasonable approach to make if you have no reason to believe it is possible.

The world he was modeling in the 18th century is a very different world than we ended up getting. IMO it's neither right nor wrong, it's just a reasonable observation that made sense for the time.

It's somewhat analogous to Y2K, in that there were obvious problems that were going to happen. We didn't experience those negative outcomes because immense engineering effort solved the underlying problem. That doesn't mean Y2K was "invalid" or "wrong," just that the problem itself got addressed before it could blow up. Same with Malthus, chemistry and mechanization allowed us to solve the underlying issue of food production scaling slower than population growth.

Not really my point. Malthus was wrong about a future food crisis, but that doesn't invalidate the tools he used to make that prediction. Re-read the first line of my original post, it's pretty clearly about the theory and not his predictions.

The underlying idea is that population growth outpaced food production, and we know it is bad for food consumption exceed production.

> And you missed one point with your discussion of linear and exponential

You're also missing the forest for the trees: agriculture and population growth can be any two functions for the idea to work, so long as the agriculture function starts higher than the population function (technically there is a third function implicitly here connecting population growth to food consumption) and grows slower. Population growth was approximately exponential, and food production was approximately linear. This is a sufficient condition to forecast future changes. Pick any overfit function you'd like for food or population as it was known to Europe in the 1790s, and you will arrive to the same conclusion if you do not "cheat" and allow for magical technology advances in 50 years.

> How much more wrong does he have to be before you are willing to call him "wrong"?

Math would have to change to the point that subtracting consumption from production no longer leads to a negative number for me to consider him "wrong."

Now, I wouldn't say his model was relevant to famine after technology changed, because it no longer was useful for that particular thing. But the core notion of "if demand grows faster than supply, you will eventually hit a crisis when they intercept" is a pretty clear-cut conclusion to draw.

It is a bit odd for a thread to get this heated over a pretty simple economic theory that stopped being relevant a century ago. Is there some political side to Malthus I am missing?

No, it is not meant to work that way.

The situation were formed by pretty predictable and easy to model factors, and if the science have failed even with that, how can we right now trust it with the things that are obviously way harder to predict?

You think if, say tomorrow, all 1.4 billion citizens in China were teleported into the U.S., that there would now be 1.7 billion Americans, indistinguishable from the Americans that came before? Or, would it simply be 1.4 billion Chinese, alongside ~300 million Americans (if we're being generous...)?

Demographics and culture are obviously intrinsically tied, each individual migrant holds beliefs and values that have been forged and shaped over the span of the lives that they have lived in their country of origin. This is, and has always, been the case, its just more of a hot-button issue recently because:

A: We are currently getting an overwhelming amount of migration to stave off our own demographic issues, so the strain begins to have a more noticeable impact,

and B: Many of the migrants (from abroad) are coming from countries with cultures intrinsically incompatible with values Westerners have come to expect in their own countries (See: Sharia Law as contrasted with Women's Suffrage), so they stick out somewhat like a sore thumb when advocating to enact such policies and practicing such cultures.

At this point in many countries the institutions of power have been captured by the owners of capital and many of the issues facing modern society are a direct result of this.

People will always act in their best interest and along the interests of their class, and no class is more class conscious than the capital owning class. In the US, this informs policy, which is generally geared at making the capital owning class more money at the expense of everyone else.

I don't see any other reason for us to have such excess and have it all seemingly go to waste. We could solve world hunger right now with our advances in technology and [corporate] central planning but that would never happen under this economic system.