Diderot ou le matérialisme désenchanté.Philosophie biologique et épistemologie.

The famous image of the «matérialisme enchanté» of Diderot, conceived by E. De Fontenay around the end of the 70s of last Century, outcome of the intellectual movement of 1968, has positively inspired an enthusiastic generation of researchers and interpreters of the philosopher of Langres, first and foremost the master of the fragment and the rhapsody, the musician of words. Reference figu - re for the whole libertarian thought which seeks support in the history of ideas. However, this approach has, long time, prevented to recognize the profound unity and systematicity hiding in the thinking of Diderot in the two aspects of epistemology and the representation of the world of life. Our paper tries to shed light on the fundamental pillars of this unified philosophy, from the point of view of a disenchanted materialism acting with great energy to achieve l’Entzauberung der Welt (M. Weber), the disenchantment of the world that characteri - zes the trial of natural sciences of the modern age. Four pillars of this materia - lism of Diderot: the ontological monism, the methodological monism, the refusal of final causes and of Newton’s corpuscularism, with important and consequential effects in the context of practical philosophy and politics («fatalisme», the materiality of the soul, the anti-despotism, and atheism). Following this line it will come to realize the originality of philosophy of Diderot, leading to a new theory of knowledge, based on the idea of nature in perpetual transformation («trasformisme») and on a new concept of «individu». This materialism of Diderot has yet to be discovered and properly appreciated.