 Philosophers in the Scottish Enlightenment argue that social order arises from aggregates of individuals interacting with one another, even if the individuals did not plan the order. “Nations stumble on establishments”, Ferguson 1767 writes, “which are indeed the result of human action, but not the execution of any human design”. Later attempts to develop a rigorous science of the social world also employ a similar picture of the components of society. J.S. Mill builds on Comte 1830–1842 to argue that social science is a branch of psychology. Society, according to Mill, is the aggregate of human minds, and the topic of the social sciences is to derive laws governing such aggregates. (Mill 1843) Altogether, his approach to social phenomena is “psychologistic”: he takes social phenomena to be built exclusively out of psychological states of individual people. (The interpretation and expansion of psychologism becomes an important topic in twentieth century individualism; see sections  3.1  and  3.2.)