Lynne Kiesling’s excellent post  on the Scottish Enlightenment is worth reading.
I read it just after reading this cover story  in the new National Geographic – a story asking if Darwin was wrong and answering, convincingly, “no!” The only flaw in the story that this non-biologist detects is that it too-uncritically repeats the common claim that T.R. Malthus was the great influence from social-science on Darwin’s thinking.
I’ve always liked Stephen Jay Gould’s revision of Malthus’s role in affecting Darwin’s thought. Consider these passages from one of Gould’s finest essays, “Darwin’s Middle Road,” appearing in Gould’s 1980 collection, The Panda’s Thumb .
Gould cites an article from a 1977 issue of The Journal of the History of Biology in which the author, Silvan Schweber, researched in detail Darwin’s reading just after the great naturalist returned from the Galapagos Islands on the Beagle. Here’s what Darwin read that Schweber found to be most influential on Darwin’s thought:
– Auguste Comte’s Cours de Philosophie Positive
– various works of the Belgian statistician Adolphe Quetelet
– Dugald Stewart’s On the Life and Writing of Adam Smith
About the first, Gould says that Darwin “was particularly struck by Comte’s insistence that a proper theory be predictive and at least potentially quantitative.”
About the second, Gould reports that Darwin got a much better statement of Malthus’s theory of population and food-supply growth.
About Stewart’s intellectual biography of Adam Smith, Gould has this to say: “[Darwin] imbibed the basic belief of the Scottish economists that theories of overall social structure must begin by analyzing the unconstrained actions of individuals.”
Gould goes on:
The theory of natural selection is a creative transfer to biology of Adam Smith’s basic argument for a rational economy: the balance and order of nature does not arise from a higher, external (divine) control, or from the existence of laws operating directly upon the whole, but from struggle among individuals for their own benefits.
The more you learn about the Scottish Enlightenment in general, and about Adam Smith in particular, the more struck you are by the out-and-out genius and vision of those great Scots.