This paper explores Adam Smith’s conception of philosophy, especially its relationship to common life (politics/religion) and natural philosophy (science). First, it is offered a summary of Smith’s naturalistic interpretation of Newton’s natural philosophy contrasting it with Hume’s and Berkeley’s views. Then, Eric Schliesser turns to explain the dual political role of philosophy for Smith: as an adviser to statesmen, philosophy helps design an equitable, institutional framework; within the polity, philosophy can help vaccinate the citizens against the dangers of religion and factionalism. Finally, he analyzes Smith’s multi-faceted response to Rousseau, pointing out that Smith’s argument with Rousseau proceeds on at least two levels: one concerns the proper understanding of modern Republicanism; the other concerns the proper self-understanding of the theoretical viewpoint. Schliesser´s account seeks to undermine popular conceptions of Smith’s philosophy, i.e., those that see Smith as a straightforward defender of a market-place of morals and political economy. Rather —he argues in this paper— Smith offers an endorsement of commercial life, in part, as a means to philosophy. The debate with Rousseau is illuminated by a careful, new analysis of the oft-cited ‘deception of nature’ passage in The Theory of Moral Sentiments.