Whose theories of population growth helped Darwin form his theory?

Answer 1

Malthus.

Answer 2

If you mean his on the Origin of Species, then no-ones - Darwin was a geologist who on a two-year round the world trip observed that some species of animals existed in some areas, but not in other nearby areas, particularly in island groups. He reasoned that either God had created many species and placed them in extremely localised places, or that geographical separation and time caused animals to adapt to their differing environments and develop/change significantly. He concluded from his own observations that animal life is not static, but species evolve and chnage.

Answer 3

Malthus

Rev. Thomas Robert Malthus, FRS (February, 1766 – December 23, 1834), was an English demographer and political economist. He is best known for his pessimistic but highly influential views on population growth.

In 1805 he became Britain's first professor in political economy at the East India Company College at Haileybury in Hertfordshire. His students affectionately referred to him as "Pop", or "Population" Malthus. In 1818, he was selected as a Fellow of the Royal Society.

In An Essay on the Principle of Population, first published in 1798, Malthus made the famous prediction that population would outrun food supply, leading to a decrease in food per person.

He even went so far as to specifically predict that this must occur by the middle of the 19th century, a prediction which failed for several reasons, including his use of static analysis, taking recent trends and projecting them indefinitely into the future, which often fails for complex systems.

"The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race. The vices of mankind are active and able ministers of depopulation. They are the precursors in the great army of destruction, and often finish the dreadful work themselves."

"But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands. Should success be still incomplete, gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world."

Accprding to Malthus, Only natural causes (eg. accidents and old age), misery (war, pestilence, and above all famine), moral restraint and vice (which for Malthus included infanticide, murder, contraception and homosexuality) could check excessive population growth.

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Presumably the connection with Darwin and "survival of the fittest" is a matter of which members of a species survive when there isn't enough food, or some other disaster strikes down some members of a group. Why do those individuals survive and not others?

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Eight major points regarding evolution are found in the 1798 Essay:

Population level is severely limited by subsistence

When the means of subsistence increases, population increases

Population pressures stimulate increases in productivity

Increases in productivity stimulates further population growth

Since this productivity can never keep up with the potential of population growth for long, there must be strong checks on population to keep it in line with carrying capacity.

It is through individual cost/benefit decisions regarding sex, work, and children that population and production are expanded or contracted.

Checks will come into operation as population exceeds subsistence level.

The nature of these checks will have significant
effect on the rest of the sociocultural system—Malthus points specifically to misery, vice, and poverty. (See Frank W. Elwell, 2001, A Commentary on Malthus' 1798 Essay on Population as Social Theory, The Edwin Mellon Press for an extended exposition.)

It is this theory of Malthus—not some easily dismissed prediction—that has had huge influence on evolutionary theory in both biology [as acknowledged by Darwin and Wallace] and the social sciences [such as Spencer].

Malthus's population theory has also profoundly affected the modern day ecological-evolutionary social theory of Gerhard Lenski and Marvin Harris. He can thus be regarded as an element of the canon of socioeconomic theory.

The influence of Malthus

The influence of Malthus's theory of population was substantial. Michael H. Hart published a book called The 100: A Ranking of the Most Influential Persons in History in 1978 which placed Malthus at number 80 in this worldwide ranking. Ironically, Malthus did not make the top 100 Greatest Britons.

At Haileybury, Malthus developed a theory of demand supply mismatches which he called gluts. Considered ridiculous at the time, his theory was a precursor to later theories about the Great Depression, and to the works of admirer and economist John Maynard Keynes.

Previously, high fertility had been considered an economic advantage, since it increased the number of workers available to the economy. Malthus, however, looked at fertility from a new perspective and convinced most economists that even though high fertility might increase the gross output, it tended to reduce output per capita.

Malthus has been widely admired by, and has influenced, a number of other notable economists such as David Ricardo (whom Malthus knew personally) and Alfred Marshall.

A distinguished early convert was British Prime Minister, William Pitt The Younger. In the 1830s Malthus's writings strongly influenced Whig reforms which overturned Tory paternalism and brought in the Poor Law Amendment Act of 1834.

Concerns about Malthus's theory also helped promote the idea of a national population Census in the UK. Government official John Rickman was instrumental in the first modern Census being conducted in 1801.

Malthus was proud to include amongst the earliest converts to his population theory the leading creationist and natural theologian, Archdeacon William Paley whose Natural Theology was first published in 1802. Both men regarded Malthus' Principle of Population as additional proof of the existence of a deity.

Ironically, given Malthus's own opposition to contraception, his work was a strong influence on Francis Place (1771–1854), whose Neo-Malthusian movement was the first to advocate contraception. Place published his Proofs on the Principle of Population in 1822.

Malthus’s idea of man’s “Struggle for existence” had decisive influence on Charles Darwin and the theory of evolution. Other scientists related this idea to plants and animals which helped to define a piece of the evolutionary puzzle. This struggle for existence of all creatures is the catalyst by which natural selection produces the “survival of the fittest”, a phrase coined by Herbert Spencer.

Darwin, in his book The Origin of Species, called his theory an application of the doctrines of Malthus in an area without the complicating factor of human intelligence. Darwin, a life-long admirer of Malthus, referred to Malthus as "that great philosopher" (Letter to J.D. Hooker 5th June, 1860) and wrote in his notebook that "Malthus on Man should be studied".

Wallace called Malthus's essay "...the most important book I read..." and considered it "the most interesting coincidence" that both he and Darwin were independently led to the theory of evolution through reading Malthus.

Thanks to Malthus, Darwin recognised the significance of intraspecies competition between populations of the same species (eg. the lamb and the lamb), not just interspecies competition between species (eg. the lion and the lamb). Malthusian population thinking also explained how an incipient species could become a full-blown species in a very short timeframe.

The significance of Malthus's influence on Darwin was perhaps best highlighted by Robert M. Young (Darwin's Metaphor: Nature's Place in Victorian Culture, 1965), Professor of Psychotherapy and Psychoanalytic Studies at Sheffield University, England.

Founder of UNESCO, evolutionist and Humanist, Julian Huxley wrote of "The Crowded World" in his Evolutionary Humanism (1964), calling for a World Population Policy. Huxley was openly critical of Communist and Catholic attitudes to birth control, population control and overpopulation.

Today world organisations such as the United Nations Population Fund acknowledge that the debate over how many people the Earth can support effectively started with Malthus.

Julian's brother, Aldous Huxley, author of Brave New World, also seems to have been influenced by Malthusian theories on population. In Brave New World, the popular form of birth control is known as the Malthusian Belt. It is mentioned frequently by the females in the novel including the female protagonist Lenina Crowne.

Karl Marx's social determinism has its roots in Malthus’s theory as well. Marx however rejected Darwin’s biological determinism and instead embraced social determinism (in other words one’s decisions are made as a direct reaction to one’s circumstances).

He saw social ills as caused by unjust or faulty institutions and social arrangements in large part caused by capitalism.

Malthus continues to have considerable influence to this day. One famous recent example of this is Paul R. Ehrlich, author of The Population Bomb. Ehrlich predicted, in the late 1960s, that hundreds of millions would die from a coming overpopulation crisis in the 1970s, and that by 1980 life expectancy in the United States would be only 42 years.

Other famous examples are the 1972 book The Limits to Growth from the self-styled Club of Rome, and the Global 2000 report to the then President of the United States of America. Science-fiction author Isaac Asimov issued many appeals for population control reflecting the perspective articulated by people from Thomas Malthus through Paul R. Ehrlich.

Malthus is widely regarded as the founder of modern demography. Malthus had proposed his Principle of Population as a universal natural law for all species, not just humans. Instead, today, his theory is widely regarded as only an approximate natural law of population dynamics for all species. This is because it can be proven that nothing can sustain exponential growth at a constant rate indefinitely.

Nonetheless, Malthus continues to openly inspire and influence even futuristic visions, such as those of K Eric Drexler relating to space advocacy and molecular nanotechnology. As Drexler put it in Engines of Creation: "In a sense, opening space will burst our limits to growth, since we know of no end to the universe. Nevertheless, Malthus was essentially right."

Malthus's arithmetic model of food supply is almost universally rejected as it can be clearly demonstrated that food supply has kept pace with population for the past two centuries (see below).

The Marxist Critique of Malthus

The highpoint of opposition to Malthus's ideas came in the middle of the nineteenth century with the writings of Karl Marx (Capital, 1867) and Friedrich Engels (Outlines of a Critique of Political Economy, 1844), who argued that what Malthus saw as the problem of the pressure of population on the means of production was actually that of the pressure of the means of production on population.

They thus viewed it in terms of their concept of the labor reserve army. In other words, the seeming excess of population that Malthus attributed to the seemingly innate disposition of the poor to reproduce beyond their means was actually a product of the very dynamic of capitalist economy.

Engels called Malthus's hypothesis "...the crudest, most barbarous theory that ever existed, a system of despair which struck down all those beautiful phrases about love thy neighbour and world citizenship."