In Essay on the Principle of Population,Malthus proposes the principle that human populations grow exponentially (i.e., doubling with each cycle) while food production grows at an arithmetic rate (i.e. by the repeated addition of a uniform increment in each uniform interval of time). Thus, while food output was likely to increase in a series of twenty-five year intervals in the arithmetic progression 1, 2, 3, 4, 5, 6, 7, 8, 9, and so on, population was capable of increasing in the geometric progression 1, 2, 4, 8, 16, 32, 64, 128, 256, and so forth. This scenario of arithmetic food growth with simultaneous geometric human population growth predicted a future when humans would have no resources to survive on. To avoid such a catastrophe, Malthus urged controls on population growth.
On the basis of a hypothetical world population of one billion in the early nineteenth century and an adequate means of subsistence at that time, Malthus suggested that there was a potential for a population increase to 256 billion within 200 years but that the means of subsistence were only capable of being increased enough for nine billion to be fed at the level prevailing at the beginning of the period. He therefore considered that the population increase should be kept down to the level at which it could be supported by the operation of various checks on population growth, which he categorized as "preventive" and "positive" checks.
The chief preventive check envisaged by Malthus was that of "moral restraint", which was seen as a deliberate decision by men to refrain "from pursuing the dictate of nature in an early attachment to one woman", i.e. to marry later in life than had been usual and only at a stage when fully capable of supporting a family. This, it was anticipated, would give rise to smaller families and probably to fewer families, but Malthus was strongly opposed to birth control within marriage and did not suggest that parents should try to restrict the number of children born to them after their marriage. Malthus was clearly aware that problems might arise from the postponement of marriage to a later date, such as an increase in the number of illegitimate births, but considered that these problems were likely to be less serious than those caused by a continuation of rapid population increase.
He saw positive checks to population growth as being any causes that contributed to the shortening of human lifespans. He included in this category poor living and working conditions which might give rise to low resistance to disease, as well as more obvious factors such as disease itself, war, and famine. Some of the conclusions that can be drawn from Malthus's ideas thus have obvious political connotations and this partly accounts for the interest in his writings and possibly also the misrepresentation of some of his ideas by authors such as Cobbett, the famous early English radical. Some later writers modified his ideas, suggesting, for example, strong government action to ensure later marriages. Others did not accept the view that birth control should be forbidden after marriage, and one group in particular, called the Malthusian League, strongly argued the case for birth control, though this was contrary to the principles of conduct which Malthus himself advocated."
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"Thomas Malthus (1766-1834) published his theory of population ("An essay on the principle of population") in 1798. In it he laid out the argument that there existed in the world a constant pressure towards population growth which was counteracted throughout history by "positive checks" that included "war, famine, and disease". He argued that food shortages, in particular, were inevitable as population grew because population could grow geometrically (build upon itself: 2,4,8,16...) whereas food production could grow only arithmetically (2,3,4,5...). Hence, according to this "Malthusian Equation", population would soon outstrip available food. A rise in population would soon be checked by a rise in the death rate. Malthus was a clergyman in the Church of England, and ultimately he argued that this balance was part of the Divine Order of the world . One consequence of this was that the Church of England opposed birth control up until the 1930s.
Much of his argument was directed at the relative growth of different classes within the population of England. Those who did not practice "preventative checks" on their family size would soon outstrip their means and so fall in status. For Malthus the only acceptable preventative check was delaying marriage until one was financially able to support a family. Birth control, inside or outside of marriage, he viewed as a "vice" (an "improper art") that threatened the moral order of society. Ultimately, in his view, poverty existed because of growth in family size caused by a lack of self restraint, and the poor, as a class, had entirely themselves to blame for their situation. Therefore he opposed "Poor Laws" that would provide support to the poor on the grounds that such support would only reinforce their lack of restraint at the expense of others in society. Such laws would undermine the fabric of society
In the world today one hears various echoes of Malthus: First, in the view that ultimately population growth is the cause of poverty, famine and environmental degradation; second, in the arguments of Garrett Hardin regarding the "Tragedy of the Commons"; and third, in the "welfare" debate in the United States in which some argue that welfare is the cause of single parenthood. Such views are termed "Neo-Malthusian".
Incidentally,
Malthus was by no means the first to think in "Malthusian" terms:
"What most frequently meets our view (and occasions complaint), is our teeming population: our numbers are burdensome to the world, [The earth] scarcely can provide for our needs; as our demands grow greater, our complaints against nature's inadequacy are heard by all. The scourges of pestilence, famine, wars, and earthquakes have come to be regarded as a blessing to overcrowded nations, since they serve to prune away the luxuriant growth of the human race."
Tertullian
(c. 155-220)De anima"
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