Opinion publique e nozione di affaire nella Francia del XVIII secolo: Voltaire difensore di Calas

This article focuses on the famous case of Jean Calas’s trial and on the defense made by Voltaire after Calas’ death. Voltaire’s complex operation succeed in mobilizing public opinion and was resumed in the well known Traité sur la tolérance, an early example of the typical scheme of the affaire. Through the analysis of the public opinion in France during the XVIII century, we will demonstrate the ambivalence of Voltaire’s thoughts in relation to this concept: one one side reign of the irrationality, when linked to the local reality, on the other, source of truth when enlightened and universal.