French Eighteenth-Century Materialists and Natural Law

This article looks at the discussions of natural law by the eighteenth-century French materialists Julien Offray de La Mettre, Denis Diderot, Paul Thiry d'Holbach and Claude-Adrien Helvetius. It is particularly concerned with their discussion of moral values and their attempt to find a materialistic basis for them as part of their rejection of religion. The discussion brings out the differences between them and analyses their dialogues on this question, including the other materialists' rejection of La Mettrie's amoralism, which threatened to undermine their attempt to found a natural law taught by experience and based on human nature. Particular attention is paid to Diderot's many writings which grapple with the subject, beginning with his Encyclopedie article droit naturel, probably written in 1754. He discussed the question in many of his later writings, including in his annotations on the works of Helvetius, who based natural law on the general interest. These writings reveal a tension between Diderot's emphasis on the search for individual happiness and the interests of society as he, together with d'Holbach, attempted to provide a natural basis for morality and government from which to criticise existing institutions.