[The natural dream: physiology of dreaming in the 18th century]

To give back dreaming to reason, to remove from it "that which is marvellous, supernatural and often terrible for the common man who studies it seriously", that is the intention of Jérôme Richard and Samuel Formey, who were both contemporaries of the philosophers of the Age of the Enlightenment. Relying on the medical theories of the time as well as on the explanatory models of physiology and psychology, they try to demonstrate "the true cause of dreaming" and the natural character of the oneiric phenomenon. The transmission of sensations, the working of memory and the association of ideas, the nature and power of imagination, the predetermined or random character of dreams constitute the framework of the questions from which the explanation of "all this apparent confusion" is developed.