Abstract

This paper wishes to offer a historical derivation of the mature Diderot’s fully materialistic, physiological theory of the soul, and to show the conflict between the theological concept of the soul as a principle of freedom, and the materialistic-deterministic concept of the soul, in his philosophical and literary oeuvre. In historical respect, Diderot formulated his mature position on the basis of Locke’s theory of ‘thinking matter’, of Toland’s idea that ‘action is essential to matter’, of Maupertuis’s theory of ‘spontaneous creative degeneration’. We present and analyze these theories one by one, together with Voltaire’s propaganda of the Lockean conception. Next, d’Alembert’s orthodox philosophy of the soul is examined, as this was Diderot’s immediate target in Le Rêve d’Alembert. The last chapters of the paper describe the afore-mentioned conflict within Diderot’s philosophy of the soul. We reach the conclusion that in Diderot’s theory, soul as a not fully determined substance still seems the ‘differentia’ of man from the rest of the living beings, though he would certainly argue that our freedom is very limited. A philosophical comparison with Kant’s account of human freedom closes the article