Between the composition of the Essays on the Law of Nature and that of the Two Treatises Locke's life changed in many different ways. It is not here appropriate nor would it for these purposes be particularly illuminating to examine these developments at length. But the main axis of the change is of the greatest importance. It can be identified with some assurance in the geographical transition from Oxford to Thanet House and in the occupational transition from academic medicine to political and administrative service in the Shaftesbury household and thus at times in the national government. The academic world was deserted, at least as major focus of interest and activity, for the diplomatic and then for the political. Interpreting the world as an activity was henceforth always to be conducted as a part of the attempt, however modestly, to change it. It was not that the academic roles, the studentship at Christ Church, the medical research, the investigation of the cognitive basis of morals were abandoned. Rather, their rationale was subtly altered and the purchase of his mind upon the world correspondingly transformed. We do not really know just what caused this change. There is a good deal of circumstantial evidence and some points are clear enough—most notably Locke's lack of enthusiasm for remaining in a fully academic and more especially an ecclesiastical role.