Thomas Malthus

Thomas Malthus was a positive influence to Charles Darwin. He wrote An Essay on the Principle of Population. Malthus says that if we don’t keep in check our food supplies, human population could double every 25 years. In other words, population size increases exponentially while food supplies remain relatively stable. He was arguing for population growth. He could also apply this to nonhuman organisms. This could be why there is a competition for food. Malthus' view that poverty and famine were natural outcomes of population growth and food supply was not popular among social reformers Malthus was a political economist who was concerned about, what he saw as, the decline of living conditions in nineteenth century England. He blamed this decline on three elements: The overproduction of young; the inability of resources to keep up with the rising human population; and the irresponsibility of the lower classes. To combat this, Malthus suggested the family size of the lower class ought to be regulated such that poor families do not produce more children than they can support. The central theme of Malthus' work was that population growth would always overpower food supply growth, creating perpetual states of hunger, disease, and struggle.

 What struck Darwin in Essay on the Principle of Population (1798) was Malthus's observation that in nature plants and animals produce far more offspring than can survive, and that Man too is capable of overproducing if left unchecked. He realized that producing more offspring than can survive establishes a competitive environment among siblings, and that the variation among siblings would produce some individuals with a slightly greater chance of survival. Darwin considered that some of the competitors in Malthus' perpetual struggle would be better equipped to survive. Those that were less able would die out, leaving only those with the more desirable traits

 Thomas Malthus' work helped inspire Darwin to refine natural selection by stating a reason for meaningful competition between members of the same species. "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 favorable 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".

Charles Darwin, from his autobiography. (1876).

Darwin was skeptical about publishing his book. He knew his work would cause a huge controversy. His wife Emma was very religious and was afraid that this would cause a problem for her. He in no way wanted to cause problems for her in the church community. He was also afraid that it would threaten his friend’s status quo and his so he hesitated.

http://www.ucmp.berkeley.edu/history/malthus.html