All of Malthus’ predictions have come true. They just did so in his past, not future. Malthusian model is the standard one to describe evolution of human populations up until 17th century or so. If you are familiar with scientific literature, with economic history, with population genetics etc, the Malthusian model is pretty much the consensus view these days. See, for example Gregory Clark’s “Farewell to Alms” or Shennan’s “First Farmers of Europe”.
The biggest fail of Malthus was that he made his argument at exactly the worst possible time, when the growth in productive capacity has for the first time in history exceeded the growth in population. However, since at his time, the past was much more of a mystery than it is now, predicting the past was almost as difficult back then as predicting the future. Since his predictions have been completely validated by the historical and archeological record we have since then recovered, this must be credited to him.
So what words you are using for astronomers and their theories of stars and galaxies? After all, almost all of the events they observe and test their theories on have happened in the long, long past. If you don’t call it “prediction”, then what?
The crucial issue is not when the event happened chronologically, but rather whether you have knowledge of the event. If you have knowledge, then indeed it is not prediction. However, in Malthus time, there was very, very little historical econometric data available.
The point here is that if you judge Malthus by quality of his predictions for immediate future, then yes, they turned out badly. However, that’s not because his model was wrong, but rather because some of his assumptions, that have been valid for entirety of the past history before him, have just stopped being valid anymore.
Thank you, I think that's very useful historical context. Yes Malthus had useful and valuable insights, but also yes we have since discovered mechanisms and processes that can largely mitigate these risks which he could not have foreseen.
Yes, we quite obviously have much higher carrying capacity, thanks to improvements in farming technology and in expanding farming into places that haven’t been farmed before. Right now, Europe has more forests and less farmland in use than it had during medieval times, despite having much higher population.
We devised ways to mitigate the problems associated with population growth, but we have not solved it: the fundamental logic of Malthus is still very much valid. The carrying capacity of Earth may be much larger than he thought: it may be 50 billion, or 100, or 500 (but probably not 1 trillion), some people surely have created an analysis to get a good estimate given current technology and available land. But, make no mistake, it is very much finite. The good news is that with current trends in population growth, we aren’t likely to hit it in the next few hundred of years.
The real death knell is that technological growth grows with population, which means that until some kind of discontinuity is hit the population won't ever be able to hit the carrying capacity before the capacity is increased again. Is there a way to support a trillion people? I can't see one, but technological progress has been doubted before, and rarely correctly.
Mitigate, or offload? Instead of facing a global famine, we're causing a global ecological catastrophe. The world didn't end, but species are rapidly going extinct, and it's only a matter of time before it comes back to bite us.
I have no opinion about your broader argument (that Malthus' model is accurate with respect to his past) but the way you choose to express it simply makes no sense.
You can't use the word "prediction" if you're unwilling to make a distinction between the past and future.
Of course you can. The crucial distinction is not about actual chronology, but rather about your state of mind. The scientific method is about predicting the outcomes of experiments, natural or artificial ones. It works just as well regardless of whether the thing you are trying to predict happened in the past or is yet to happen.
Otherwise, the whole field of astronomy wouldn’t be possible, as it by its nature is all about observing the past, and building models to explain and predict other events that happened in the past. If you grant that astronomy is a scientifically sound pursuit, why is astronomy observing and testing their theories on events that happened thousands or millions year ago in another galaxy fine, but observing and testing econometric theories on events that happened hundreds or thousands years ago make no sense? How is archeology, or ancient population genetics supposed to work, if you only allow scientific method to be applied to future events?
You're making a tortured semantic argument. We were talking about whether Malthus is still relevant, whether we can still use him to make predictions. Malthus being "correct up until the 17th century" is beside the point.
You've also made bizarre arguments elsewhere in this thread. Apparently Malthus can't be proven wrong because the Earth can't support an infinite number of people. That's true, of course, but it's not a model. It's the statement of an obvious fact.
> We were talking about whether Malthus is still relevant, whether we can still use him to make predictions.
We can, and we do, just not for human population in future. Again, Malthusian models are completely standard way to model past human populations, and also animal populations.
> Apparently Malthus can't be proven wrong because the Earth can't support an infinite number of people. That's true, of course, but it's not a model. It's the statement of an obvious fact.
Yes, that's why Malthusian model is so popular: because it is obviously correct, and because its assumptions cover very wide range of observed past and future conditions. We live in pretty unique circumstances when they don't: we both had the technology grow carrying capacity faster than the population had grown, and also we had population growth slow down a lot, and then go down to shrinking regime.
I expect these trends to continue in my lifetime, and probably in the lifetime of my children -- but not forever. Instead, I believe that in around 200-300 years we will return to high-fertility regime, that will require governmental measures to curb, if we want to preserve the quality of life. However, I have much less confidence in this prediction than I do in the validity of Malthusian model.
> Yes, that's why Malthusian model is so popular: because it is obviously correct
It's not correct right now, for humans, which is what we were talking about.
> and because its assumptions cover very wide range of observed past and future conditions
Ah yes, those magical "observed future conditions".
> We live in pretty unique circumstances when they don't
There are no grounds for insisting that we "live in unique circumstances". That statement is either a tautology (like your interpretation of Malthus) or it's meaningless.
> I believe that in around 200-300 years we will return to high-fertility regime, that will require governmental measures to curb, if we want to preserve the quality of life.
I like science fiction as much as the next person but that's all this is.
The biggest fail of Malthus was that he made his argument at exactly the worst possible time, when the growth in productive capacity has for the first time in history exceeded the growth in population. However, since at his time, the past was much more of a mystery than it is now, predicting the past was almost as difficult back then as predicting the future. Since his predictions have been completely validated by the historical and archeological record we have since then recovered, this must be credited to him.