It would be scarcely fair to convict Malthus of error on the ground that he failed to foresee the astonishing development of transport and colonization which took place in the 19th century and has increased so enormously the area from which foodstuffs and raw materials can be drawn during that period. On the other hand, he did undoubtedly underestimate the importance of the reactions of industrial progress upon the output and cost of production of agricultural produce. There is some truth in the contention of those who disagreed with him that, while every addition to the population means another mouth to feed, it also implies another pair of hands. The law of increasing returns has operated very powerfully in industry and the influence of in ventions and new methods of cultivation have held in check that recourse to poorer soils which Malthus gleaned must result from any growth of population. Furthermore, progressive standards of living have contributed to raise the marriage age and lower the birth rate in western countries to a far greater extent than Malthus would ever have dared to contemplate. Even so, the decline in the death rate has been so great that the absolute rate of increase of population is still large in most countries, while in the East the Malthusian "principle" still seems to reign supreme.
Malthus's views influenced public opinion in the first half of the 19th century, yet later it had become common to disparage his doctrines as out of date. Since the European War of 1914-18, however, the spectre of over-population has returned and Malthus is coming into his own again.
A chance reading of the Essay, in which the phrase "struggle for existence" struck an answering chord, stimulated Charles Darwin to find the key to biological change in the process of natural selection brought about by this struggle for existence.
Malthus was also a writer of considerable importance for the development of economic theory. The close friend and correspond ent of Ricardo, he not merely stimulated the latter but himself made independent contributions to the theory of value. He is generally credited with being the first writer to formulate the law of diminishing returns as applied to agriculture, though he did not call it by this name and perhaps himself failed to realize the full significance of this conception. He combated the rigid Ricardian labour cost theory of value and adumbrated a theory which was much closer to that of most modern economists.
Besides his great work, the first edition of which was reprinted by the Royal Economic Society in 1926, Malthus wrote Observations on the Effect of the Corn Laws: An Inquiry into the Nature and Progress of Rent; Principles of Political Economy; and in Political Economy. His views on rent were of real importance.
For his life see Memoir by his friend Dr. Otter, bishop of Chichester (prefixed to 2nd ed. 1836, of the Principles of Political Economy), and Malthus and his Work, by J. Bonar (London, i885) ; see also Soetbeer, Die Stellung der Sozialisten zur malthusschen Bevolkerungs lehre (Berlin, i886) ; G. de Molinari, Malthus, essai pour le de population (Paris, i889) ; Cossa, Principio di popolazione T. R. Malthus (Milan, i895) ; and Ricardo, Letters to Malthus, ed.
Bonar (1887). (C. W. G.)