“Social Darwinism” means almost as many things as there are people who have written on it; but this paper takes it to be a generic term for theories of human social development and maintenance which are in some way inspired by biological evolutionary theories—this “inspiration” could take the form of seeing human sociality as a straight extension of the animal (and perhaps plant) domain, or it could involve some sort of analogy. In discussion of the roots of social Darwinism two names invariably appear—that of Charles Darwin himself, obviously, and that of Herbert Spencer. Here, however is the end of agreement. Who was the more important and influential, divides scholars right down the middle; as also do the questions of who really came first and whether their doctrines were essentially the same.

Because there is so much disagreement, no one has yet adequately argued to precisely the right conclusion. To anticipate, this paper argues that both Darwin and Spencer represent fundamental advances (or, less normatively, shifts beyond) their common major source, Thomas Robert Malthus; and that although there was overlap (and undoubted mutual borrowing) their positions were fundamentally dissimilar. Consequently, a search for the roots of Social Darwinism yields two sources, Darwin and Spencer respectively, and that what came from these sources was different. This essay begins with a brief discussion of Malthus's views, paying special attention to his relevance to social Darwinian lines of thought, considers the views of Spencer and Darwin on human social structures, and concludes by comparing the two thinkers, noting their similarities, but arguing that these are far outweighed by their differences.