Mill’s defence of individual liberty rests on a conception of historical determinism that is crucial for his liberalism, but is generally misunderstood. The aim of the paper is to explore Mill’s complex view both of the historicity of human nature and of the historical factors that shape it. Avoiding the weaknesses of Bentham’s a-historical utilitarianism, Mill describes in On Liberty human beings as self-developing individuals. As a consequence, the role of society and history in that constant transformation cannot be understood (...) in naturalistic terms as in the natural sciences. In his Logic, Book VI, Mill develops his ambition to produce a “new” science of human behaviour or Ethology that would unite individual freedom and social factors in our understanding of history. (shrink)