A System of Logic was considered by John Stuart Mill to be, along with On Liberty, the work which he was best fitted to write. It is also his most difficult, and, for us, perhaps boring; yet it is crucial to an understanding of Mill. The first essential question concerning the moral sciences is: "Are the actions of man, like all other natural events, subject to invariable laws?" An affirmative answer implied the denial of man's uniqueness, his special position in God's creativity. In any case, Mill linked his Associational psychology, unmodified, to another element of his Utilitarian heritage—conjectural history—only this time updating the latter view. What he did was transmute his conjectural history into Auguste Comte's positive philosophy of history, with its law of the three stages, and emerge, under Comte's inspiration, with a form of social dynamics.