Undergraduate Economist

Perspectives of an economics student

On Malthusian Theory of Population

Posted by Alex M Thomas on May 23rd, 2008

This post revisits ‘An Essay on the Principle of Population’ written by Thomas Malthus in 1798. In my last post I briefly touched upon his population theory. Unfortunately, mainstream economics textbooks mention Malthus only for his ‘bad’ population theory. His other significant contributions like Differential Theory of Rent, his theory of money, his questions about the validity of Say’s law, etc are conveniently suppressed.

First, I would like to discuss why his theory is ‘good’ and then I would like to show how Malthus is viewed, interpreted and treated by various economists and students of economics.

Economics as viewed earlier and as viewed now (by a few) was a discipline which tried to understand the society (now known an economy) and also to come up with solutions for the problems that persist. His Essay was the first serious economic study of the welfare of the lower classes” during his times. He was also a clergyman who wanted to make the society perfect.

His two postulates were that “food is necessary to man” and that “the passion between the sexes is necessary and will remain nearly in its present state”. [Malthus 1798] Now we know that the first is a true premise and the second one is believed to be a law of nature. So, there are no issues with both his postulates. He also refers to these postulates as ‘laws of nature’.

Ceteris paribus, population growth will outstrip food growth. He also gives additional insights as to how population growth will necessarily be checked. His thought experiment based on the ‘true’ premises is therefore valid. At this juncture, one needs to understand the underlying assumption of diminishing returns to agriculture. Once this is understood, there is no reason to call his theory ‘bad’.

How can such a theory be useful to the society? It brings to the fore the need for improvements in agriculture through technological advances, so that food production can be increased. (Assuming increased food production implies lesser hunger, but Amartya Sen proved otherwise. But it is necessary to have sufficient ‘food’ to feed society) Family planning is undertaken so that no child goes hungry apart from other reasons. Such checks are welcomed by all. Also, they indirectly draw from Malthus- the need for all people to consume food. However, checks like the Chinese one child policy create social problems on a massive scale.

It is amazing that even when his theory is viewed in isolation (from his other works), it still holds good! With progress in education (school children get introduced to a lot of theories and facts at an early age) theories like Malthus’ seem obvious and hence pointless. This also reflects the way theories are taught in schools and colleges. Very often, the context of the theory is left out. Corn Laws, the then predominant Ricardian theories, etc are very often not mentioned or discussed.

Now, I shall put forth two different views on Malthus, the economist.

1)

In this famous work, Malthus posited his hypothesis that (unchecked) population growth always exceeds the growth of means of subsistence. Actual (checked) population growth is kept in line with food supply growth by “positive checks” (starvation, disease and the like, elevating the death rate) and “preventive checks” (i.e. postponement of marriage, etc. that keep down the birth rate), both of which are characterized by “misery and vice”. [Source] (Note the mention of (unchecked))

2)

Malthus believed that population would increase at a geometric rate and the food supply at an arithmetic rate.

Malthusian population theory was eventually dismissed for its pessimism and failure to take into account technological advances in agriculture and food production. [Source]

Conclusion

How should theories be taught? By this post, I only intend to question the current teaching and understanding of Malthus’ theories. Also, I wish to stress the importance of understanding and studying the ‘context’ (historical, political, social, cultural,etc) of a theory.

Now, economists (positive economics) are busy using scientific methods so as to universalise theories rather than provide solutions to hunger, poverty, unemployment and other socio-economic problems.

To sum up, Malthus stressed on the need to keep population and food production in such a way that everyone would be fed. I believe that this still holds true across the globe as one of the main concerns of economics.

Further Reading

1) 1) 1) Darwin and Malthus

2) 2) 2) Is India falling into the Malthusian trap?, C. J. Punnathara, The Hindu Business Line, April 9, 2008.

3) 3) 3) Malthus, the false prophet, May 15th 2008, The Economist.

4) 4) 4) The International Society of Malthus (further links from the society)

5) On GM Food and GM Mosquitoes

7 Responses to “On Malthusian Theory of Population”

  1. vishesh Says:

    wow alex! i think this blog will help me in my studies :) i was searching for a comprehensive source and here it is :)

    so finally the needed food is k[population]=production? or is it the other way about ?

  2. Crow Says:

    [school children get introduced to a lot of theories and facts at an early age, theories like Malthus’ [b]“seem obvious and hence pointless”[/b]. This also reflects the way theories are taught in schools and colleges. Very often, [b]“the context”[/b] of the theory is left out.]

    TRUE.

  3. Dr. Steven J. Balassi Says:

    As an Economics Professor, I wish all my students had such an interest in economics and how it can be used to better the world. I see many students majoring in economics because that is where the jobs are.

    About your post, how should theories be taught? There are too many economists who think they can find a magical mathematical formula to solve every problem. That explains why the field is so technical now. The reality is that math can not keep up because there are too many new variables. In other words, as the world grows, the math would need to change. You can take a simple theory from history and think it applies now, it may not. In the United States, we have been thinking that monetary policy is the solution to everything due to success of the Greenspan years. Now, our monetary policy is not working and Keynes is making a comeback.

    Keep an open mind and realize there is no one-size-fits-all solution to every problem.

  4. Alok Says:

    I believe that any strong believer of Darwin’s theories would accept the two basic postulates of Malthus that have been listed here (I found myself agreeing as I read them). After that it’s only about mathematics.

    Science has no room for emotions. How many of us follow that? Too few, I believe. And it is for this reason that such obvious facts of our existence are ignored.

    According to me, it’s all about Survival. Human beings have been endowed (due to evolution) with a capability to alter the surroundings (and hence the very rules of nature) so that they have come to the top of the food chain, and have modified it in a manner that ensures their survival. With this control, there is hardly any restraint on the human growth rate (which would otherwise have been stemmed by a predator).

    On the other hand, this very control has helped us in food production, but at the cost of human endeavour, which, no matter what, is a limited resource. Thus, food production remains limited and it is here that the concept of “Money”, as a substitute for the natural law of “survival”, chips in and creates a criteria for survival, that is human endeavour. So you see, it’s a circle, which itself has somehow come to simulate the laws of nature, although in a different way.

    Of course, I’m no economist, and this is just a speculative hypothesis I work with. So this isn’t meant to be serious.

  5. Fasten Says:

    Somehow i missed the point. Probably lost in translation :) Anyway … nice blog to visit.

    cheers, Fasten!

  6. Kerala Blog Roll » On the ‘Invisible’ Adam Smith Says:

    [...] Also, it is not surprising to see classical economists (Smith, Ricardo, Malthus, etc) being seen as ‘classical’ or rather irrelevant, because of either their naive assumptions or their bad theories. [...]

  7. Bookmarks about Malthusian Says:

    [...] – bookmarked by 2 members originally found by waternavy on 2008-08-19 On Malthusian Theory of Population http://alexmthomas.wordpress.com/2008/05/23/on-malthusian-theory-of-population/ – bookmarked by 6 [...]

Leave a Reply

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>