AbstractDarwin's theory of evolution encompasses both nonanthropocentric and biocentric elements. T. H. Huxley, Peter Kropotkin, and Patrick Geddes accepted the general theory and attempted to make use of it in writing about social and political questions. Huxley and Kropotkin failed to incorporate the biocentric aspects of the theory of evolution into their understanding of evolution or their thinking about society; Geddes successfully integrated biocentrism and social theory. Their failures and successes provide important lessons for contemporary social theorists.