Charles Devellennes looks at the the religious, social and political thought of the first four thinkers of the French Enlightenment: Pierre Bayle, Jean Meslier, Paul-Henri Thiry d'Holbach and Denis Diderot to explicitly argue for atheism as a positive philosophy. Atheism evolved considerably
over the century that spans the works of these four authors: from the possibility of the virtuous atheist in the late 17th century, to a deeply rooted materialist philosophy with radical social and political consequences by the eve of the French revolution. The metamorphosis of atheism from a purely
negative phenomenon to one that became self-aware had profound consequences for establishing an ethics without God and the rise of republicanism as a political philosophy. Culminating in the work of Diderot, atheism became increasingly critical of its own position. By the late 18th century, it had
already proposed to move past its positive formulation into a form of metatheism. Diderot, who sees atheism as both a critical tool to assess religious, social and political institutions and as an object of his own critique, foreshadows the rise of a post-Enlightenment conception of atheism.