Stoat

I am reminded of Kurzweil's mantra; "We live in exponential times". (Whatever the hell that is supposed to mean.)

Anyway, food is a production process: we can add to the means of production but the means of production don't add to themselves. Wheat doesn't plant itself, milk doesn't make more milk, etc. But human babies go on to have more babies. Could that have been what Malthus was thinking?

Posted by: george.w | January 3, 2009 7:45 PM

I'll second phisrow. Malthus was writing in the 1790s and all the data leading up to his work probably supported his theory.

Paul Krugman commented on this earlier this year:

The fact is that Malthus was right about the whole of human history up until his own era.

Sumerian peasants in the 30th century BC lived on the edge of subsistence; so did French peasants in the 18th century AD. Throughout history population growth had always managed to cancel out any sustained gains in the standard of living, just as Malthus said.

It was only with the industrial revolution that we finally escaped from the trap.

[ Throughout history population growth had always managed to cancel out any sustained gains in the standard of living - err yes, thatss what *I*m saying: food proportional to population. So why then suddeny assume it would decouple in the future and become linear? -W}

Posted by: Jinchi | January 4, 2009 2:17 AM

But there was also an agricultural revolution in the 18th century, wasn't there (see Wikipedia: British Agricultural Revolution)? Scott (early 19th century) satirises the optimism in The Pirate

Posted by: nigel holmes | January 4, 2009 5:23 AM

"Almost nobody has any real technical understanding of why exactly Moore's law holds; but recent history and popular consensus both bear it out, so it is treated as wholly unremarkable."

Off topic but huh? We know why Moore's law (the estimate that area size of features on silicon chips would half every two years or so - thus density double) has been (vaguely, within fairly large limits) accurate over the past several decades. I mean "we" as in modern society did the engineering to make it happen, so how could we NOT know? Moore's law is an educated guess at engineering and production capability, based on knowledge of then current and possible technologies. It is not precise in any sense, or predicated directly on natural limits. In fact when the natural limits get felt Moore's law will likely then start to be less accurate.

Posted by: Markk | January 4, 2009 11:11 AM

I found the text of his reasoning, which amazingly doesn't refer to the peer reviewed literature. :-)

------------

Let us now take any spot of earth, this Island for instance,
and see in what ratio the subsistence it affords can be supposed to increase. We will begin with it under its present state of cultivation.

If I allow that by the best possible policy, by breaking up
more land and by great encouragements to agriculture, the produce of this Island may be doubled in the first twenty-five years, I think it will be allowing as much as any person can well demand.

In the next twenty-five years, it is impossible to suppose
that the produce could be quadrupled. It would be contrary to all our knowledge of the qualities of land. The very utmost that we can conceive, is, that the increase in the second twenty-five years might equal the present produce. Let us then take this for our rule, though certainly far beyond the truth, and allow that, by great exertion, the whole produce of the Island might be increased every twenty-five years, by a quantity of subsistence
equal to what it at present produces. The most enthusiastic
speculator cannot suppose a greater increase than this. In a few centuries it would make every acre of land in the Island like a garden.

-------------------------------

Writers of that time seemed to be paid by the word. The quick summary is that the amount of arable land is limited and can only be pushed so far in terms of production. Of course this skips all types of possibilities, which is a common fault of people making predictions about the future.

[Ah, thank you. Well there you have it I suppose. Argument from imagination -W]

Posted by: Nicolas Nierenberg | January 4, 2009 4:38 PM

Somewhere I have a copy of Malthus' longer form volume on the subject that I worked on for Project Gutenberg years ago. Anyway, comments up to this point seem to capture his thinking pretty well, such as it was. Obviously when human population is low, people and agriculture can grow exponentially together, under conditions that allow expansion of agriculture into new lands. When all the land is used up, though, that growth in food must stop. Malthus' point then was that human population at that point contiunes to grow inexorably until forcibly constrained by abject poverty, war, starvation, or other "vices", that bring them back into sync.

Posted by: Arthur Smith | January 4, 2009 6:17 PM

"that forecast that England would run out of coal by 1900."

Yeah, but they probably knew there was plenty of it under Wales. ;)

Posted by: Adam | January 5, 2009 11:44 AM