Destutt de Tracy (1754–1835) was one of the main figures of the French Revolution and of French philosophy. In his famous main work, he gives a comprehensive presentation of his philosophy, which he called ‹Idéologie‹. In it, he analyzes ideas in their elements, which originate only from sensory perception. Ideas which cannot be traced back to sensory data, such as that of religion, are for him unfounded. The highly explosive political nature of his sensualistic theory is demonstrated by the persecution to which he and his adherents, the Ideologen, (ideologists) were subjected.