J. S. Mill’s protest at ‘vulgar’ uses of the past gave way in the 1830s to an eclectic science of history which drew on Samuel Taylor Coleridge, the Saint-Simonians, and Auguste Comte. Book VI of A System of Logic (1843) sketched a theoretical outline of progress whose scientific conversion came about when it was connected, indirectly, to the ultimate laws of psychology. The triumph of sociology reflected Mill’s settled view that society was increasingly a historical phenomenon, shaped less and less by the psychological laws from which Thomas Hobbes, Bentham, and the ‘geometric’ reasoners had deduced their political ideas. This realisation, Barrell argues, pulled in two directions. While it provided a logic and vocabulary of historical relativism, its theoretical sketch of progress was neither relative nor concretely historical because it encompassed the ‘whole previous history of humanity’ as a progressive chain of causes and effects. This double consciousness, I have argued, can be profitably situated within German historicism, French science sociale, and English utilitarianism, all of which acknowledged the logical dissonance between historical facts and their theoretical reconstruction.