Malthus came to prominence for his 1798 publication, An Essay on the Principle of Population. He wrote the original text in reaction to the optimism of his father and his father's associates (notably Jean-Jacques Rousseau) regarding the future improvement of society. He also constructed his case as a specific response to writings of William Godwin (1756–1836) and of the Marquis de Condorcet (1743–1794). His assertions evoked questions and criticism, and between 1798 and 1826 he published six more versions of An Essay on the Principle of Population, updating each edition to incorporate new material, to address criticism, and to convey changes in his own perspectives on the subject.
The Malthusian controversy to which the Essay gave rise in the decades following its publication tended to focus attention on the birth rate and marriage rates. The neo-Malthusian controversy, comprising related debates of many years later, has seen a similar central role assigned to the numbers of children born.[27] The goal of Malthusian theory is to explain how population and food production expand, with the latter experiencing arithmetic growth and the former experiencing exponential growth.[28] The controversy, however, concerns the relevance of Malthusian theory in the present world. This hypothesis is inapplicable in a number of ways. First, the hypothesis is rendered irrelevant,[29] due to a disregard for technological advancement. This is because food production has increased as a result of technological advancements such as genetically modified organisms (GMOs).[30] Second, the mathematical model employed to formulate the hypothesis is incorrect since it was constrained to England's specific situation.[31] Other findings, such as food production exceeding population increase, may be borne out if the modeling could employ wide locations like Australia.[32] The Malthusian hypothesis is also limited by social change about family size,[33] as individuals tend to prefer a manageable family owing to economic restrictions. Food production can also outpace population expansion, due to the industrial revolution.[34] Another limitation of this theory is the belief that overall income is a key factor of population health,[35] implying that wealthy countries will have various solutions for their rapidly rising populations.[36] An expanding population can be considered as an increase of available human capacity for increasing food production.[37] The static aspect of the Malthusian hypothesis, which is based on the rule of decreasing returns,[38] limits its applicability. Finally, Malthusian Theory's failure to determine whether birth rates match death rates hampered its application,[39] because it was possible that the population was not rising as fast as food production due to the presence of deaths.
