Thursday, October 22, 2015

Charles Darwin and Thomas Malthus

For our first assignment, we are discussing "Historical Influcenes." Here are my thoughts:

I believe the person who most influenced the development of Charles Darwin’s theory of Natural Selection is Thomas Malthus. One could say that the without the ideas presented in Malthus’ “Essay on the Principle of Population,” Darwin’s theory would have never come to exist.

Malthus was a 19th century English economist who became concerned with humankind’s ability to “outgrow” their resources. In his “Essay on the Principle of Population,” Malthus discussed animals’ ability to reproduce at exponential rates- rates that their resources could not support. This inevitably led to lower chances of survival for certain animals as they had to compete for their food. He posited that people would soon face the same challenges. He noted that people are capable of increasing their food production to support a growing population, but that the rate of increase would always be considerably less than the increase in population. He stated that dire consequences for this occurrence would include famine, poor health, and war stemming from competition for resources and food. Those who were successful in obtaining the food and resources needed for prosperous life will go on to reproduce and thrive, those who are not successful, will starve and die. This is essentially the ground work for Darwin’s theory of evolution.
Two key points that are the cornerstones of Darwin’s Theory of Evolution are supported by the ideas of Thomas Malthus. Like Malthus, Darwin believed that organisms have the potential to reproduce exponentially but are ultimately limited by the availability of resources. Though Malthus was focused primarily on human population, he states in his essay that if human population was left unchecked by limited resources resulting in disease, hardship, famine or self-constraint (birth control, marrying later in life), it would double every 25 years (An Essay on the Principle of Population, II.16).

These two ideas – that populations have the ability to grow exponentially and that they are only limited by resources- are the building blocks of the Darwin’s theory of evolution. Without the identification of what is limiting populations, Darwin would not have been able to theorize about the overall effects on a species; “who” successfully reproduced and why, a species’ ability to adapt, or the inheritance of desirable traits. In fact, Darwin even credited Thomas Malthus for the ideas presented in his essay.

From Charles Darwin’s Autobiography:

“In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long- continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work;”

                (http://www.gutenberg.org/files/2010/2010-h/2010-h.htm)

One final note on Malthus and Darwin that I found interesting: Malthus was an English cleric, a member of the clergy. Although he believed that resources were the inhibitors to human population growth, he sternly believed that this was God’s will. I find it ironic that Darwin’s theory was influenced so greatly by a non-secular scholar since Darwin’s work was heavily scrutinized by the religious community. Darwin postponed many of his publications as to not upset the church. In fact, the influence of the church could have even caused Darwin to lose credit for his theory of natural selection to Alfred Wallace. Ultimately, it was competition that led Darwin to publish his ideas (survival of the fittest?).


 Additional Web Sources:

http://www.gutenberg.org/files/2010/2010-h/2010-h.htm
http://www.econlib.org/library/Malthus/malPop1.html#Chapter II
http://www.econlib.org/library/Enc/bios/Malthus.html


7 comments:

  1. This is an excellent post. I agree with most of what you say, though I do think that it is possible for Darwin to have come up with his theory without the inspiration of Malthus. I think that though Malthus played a key role in getting Darwin to actualize his theory, Darwin did have so much inspiration from other people and I think he could very well have come up with the concept of natural selection without having the basis of Malthus's economic principle of the supply of resources versus the population. I do agree that it speaks volumes that Darwin cited Malthus as a great inspiration in creating his theory, hence my choice of Malthus for the original blog post.

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  3. Good sources.

    "Malthus discussed animals’ ability to reproduce at exponential rates- rates that their resources could not support. This inevitably led to lower chances of survival for certain animals as they had to compete for their food."

    Actually, Malthus noted that non-human populations tended to NOT outgrow their available resources. He contrasted this with human populations that seemed to not possess these natural population limiting factors and shot past their environment's carrying capacity with rapidly growing population sizes.

    "Those who were successful in obtaining the food and resources needed for prosperous life will go on to reproduce and thrive, those who are not successful, will starve and die."

    I'm not sure I would argue that Malthus went this far as to ask who was successful and who wasn't. Malthus used his observations to argue that humans needed to control their own reproduction to reduce the incidence of famine, war and disease. Other than noting that the poor seemed to suffer the greatest from these events, he didn't highlight differential access to resources. That was a logical step Darwin took after reading Malthus' work, to as the question of "who is surviving when resources are limited? Do all individuals suffer equally or are some more successful than others? If the latter, is it random or is there a pattern of greater success?"

    Great job highlighting the two key bullet points that apply to Darwin's work.

    I agree with your conclusion on whether Darwin could have developed his theory without Malthus. Good choice of supporting quote.

    "I find it ironic that Darwin’s theory was influenced so greatly by a non-secular scholar since Darwin’s work was heavily scrutinized by the religious community. "

    So do I. Malthus opposed the idea of evolution and likely would have been horrified to know that his work was so important to Darwin's theory of evolution by natural selection.

    "Darwin postponed many of his publications as to not upset the church."

    That was it? He didn't out of sensitivity to the church's feelings? :-) Let's think of how Darwin might have been negatively impacted by the church's influence by publishing his work. Could he have been hurt socially? Professionally? Might his family have been negatively impacted? His wife was very religious. Could his have influenced his decision to delay publishing? A scientist does not live in a bubble. His academic work and choices are often influenced by personal and social factors as well.

    "Ultimately, it was competition that led Darwin to publish his ideas (survival of the fittest?)."

    Good observation!

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    1. I think for your first point. my message might have been a little lost - but it was leading to the fact that resources limited population growth for animals. I should have worded it differently.

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    2. I think for your first point. my message might have been a little lost - but it was leading to the fact that resources limited population growth for animals. I should have worded it differently.

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  4. Thank you for being so clear in what you were writing about. I agree with what you had to say about Darwin and Malthus. I believe you took a lot of time thinking and writing abut this. You helped me understand everything in a better way.

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