One theological argument, of course, is that social problems are inevitable because human nature is sinful. One might think this should have settled the matter for Robert, who after all had been ordained, at around age 22, in the Church of England. But he also had studied mathematics, and shown scientific inclinations; neither he nor his father seem to have regarded their debate as essentially theological. 

Searching constantly for stronger arguments, Robert eventually hit on an idea so persuasive that he decided to publish an essay laying it out in detail. Thus it was that in 1798 he gave the world one of its great books, An Essay on the Principle of Population. The gist of his case was that humans, like other forms of life, tended to reproduce in numbers greater than could be easily supported by available resources. This mismatch between population and resources generated poverty, crime, and greed. True, periods of relief occasionally would occur after plagues had sharply reduced population, or technological breakthroughs had abruptly increased available resources (especially food); but the power of population was so great that soon there again would be too many people. Population might eventually stabilize, but it would do so at a level above that of "easy support." Relief from social problems, then, would be rare and temporary. 

A key point in Malthus' argument--which has been under nearly non-stop debate for two centuries now--has been widely overlooked: his claim that population tended to stabilize at a level greater than what resources could easily support meant that there would be not only social problems, but also nearly constant pressure for culture change. As he wrote toward the end of the Essay, the press of population "is constantly acting upon man as a powerful stimulus, urging him to the further cultivation of the earth, and to enable it consequently to support a more extended population" (1976:121). The possibility that population pressure could help explain cultural evolution would lie in neglect for a long time indeed; when scholars at last latched onto it, they would label it, ironically enough, an "anti-Malthusian" approach! 

Picture Credit: By kind permission of the Master, Fellows and Scholars of Jesus College, Cambridge.