The issue is that of experience in the way that Diderot, as a non-systematic philosopher who favours a certain amount of empiricism, deals with the notion in his fictional production, Les Bijoux indiscrets, La Religieuse (The Nun), Jacques le fataliste (Jacques the Fatalist), extended to include Le Neveu de Rameau (Rameau’s Nephew) and Éloge de Richardson (In Praise of Richardson). After an analysis of a certain number of uses of the term “experience”, some of which demonstrate the philosophical purpose at the heart of the fictions, this article establishes the recurrence of the motif of experience in the novels and examines it rapidly. The notion is finally analysed from the point of view of the author and of the reader with a more formalist approach.