1798: Darwin and Malthus
Under the Influence
As his detractors were only too happy to point out, Malthus's ideas owed a lot to his extensive reading of David Hume, Adam Smith, Robert Wallace and Joseph Townsend (for example, Townsend's Dissertation on the Poor Laws by a Well-Wisher to Mankind, 1786). In dismissing Malthus, Marx (Karl, not Groucho) complains: "If the reader reminds me of Malthus, whose 'Essay on Population' appeared in 1798, I remind him that this work in its first form is nothing more than a school-boy-ish, superficial plagiary of De Foe, Sir James Steuart, Townsend, Franklin, Wallace, &c., and does not contain a single sentence thought out by himself…" (Capital 1867). And so on, in equally dyspeptic terms. Marx had much more in common with Godwin, who had argued in his Political Justice (1793), "There is no wealth in the world except this, the labour of man. What is misnamed wealth, is merely a power invested in certain individuals by the institutions of society, to compel others to labour for their benefit."
Malthus, who was always seen by his friends as kindly and unassuming, frankly acknowledged that his "principle" was not wholly original; "I mean to place it in a point of view in some degree different from any that I have hitherto seen." That he succeeded is demonstrated by the hatred he brought on himself and by the respect with which he was treated by serious economists like David Ricardo.
Famously, reading Malthus's book (presumably its 6th edition, 1826) triggered in Darwin's mind the idea for a causal mechanism of natural selection. Darwin wrote in his Autobiography (nearly 40 years later), "… [the question] how selection could be applied to organisms living in a state of nature [as opposed to artificial selection, that is] remained for some time a mystery to me. In October, 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement Malthus on Population…."
We need to ask what Darwin may have meant by "for amusement." He had also used the term in a journal entry (August 1838): "Read of a good deal of various amusing books paid attention to Metaphysical subjects." The authors in question had been, among others, Edmund Burke, James McIntosh, Henry Lord Brougham, Dugald Stewart, Gotthold Lessing, David Hartley, Thomas Reid and David Hume. We have always known Darwin was a dour fellow, but this is not what we would call amusement. Our present meaning for the word—light entertainment, pleasurable but not serious—represents an evolution from the 17th- and 18th-century meaning of "musing; mental abstraction" by route of "distraction, or diversion of the attention, deception" and "idle, time wasting." One senses that Darwin used the word in the archaic sense and wryly—but perhaps also deprecatingly as Malthus had in a reference to Condorcet: "I refer the reader to the work itself, which will amuse, if it does not convince him."
Similarly, although the date when Darwin adroitly turned Malthus's ideas to the advantage of his own work is always set at 1838 (the authority being the Autobiography just quoted), he did not say he was then reading the book for the first time. Indeed, it is not credible that Darwin should have been previously unfamiliar with Malthus's ideas, at least. Poverty, the unemployed and the questions of Poor Relief were such a constant of early 19th-century life, that Darwin could hardly have missed the subject. His father was a capitalist and his father-in-law a major employer. Harriet Martineau, the radical social reformer, was a constant visitor to his brother's dinner table in London, and his Cambridge mentor The Reverend Henslow was a reform-minded clergyman. Darwin must have been exposed early, not only to the problem but also to Malthus's analyses.
From 1800 to 1830 "population" meant Malthus and his devastatingly simple principle. The Reverend William Paley (Natural Theology 1802), whose works Darwin virtually memorized as an undergraduate, was one of the first converts to Malthus's ideas (having earlier been very much on the Godwin side). Other authors who had referred variously to a struggle for existence or the struggle between species were known to Darwin. For example, De Candolle in 1820 wrote, "All the plants of a given country are at war one with another" (he meant species against species)—a statement that was repeated by Lyell in Volume 2 of his Principles of Geology (1832). This may well be in part what Darwin meant when he wrote that he had been "well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observance of the habits of animals and plants …" (Autobiography).
Whatever the antecedents, Darwin stated that in 1838, on reading Malthus's inexorable arithmetic, "it at once struck me that under these circumstances favorable variations would tend to be preserved, and unfavorable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work."