Theodor Adorno and Max Horkheimer, in Dialectic of Enlightenment [Dialektik der Aufklärung, first published in 1944], argue that Donatien-Alphonse-François, the Marquis de Sade (1740–1814), and Friedrich Nietzsche have brought the Enlightenment project of grounding morality in reason to an end. For Adorno and Horkheimer, Sade has revealed philosophy’s moral impotency, in particular “the impossibility of deriving from reason any fundamental argument against murder [...].”1 Marcel Hénaff, Susan Neiman, and Annie Le Brun have similarly suggested that Sade has demonstrated that morality (...) is no more philosophically justified than immorality.2 There is no doubt that there is much discussion of moral philosophy in Sade’s surviving works. But are these extraordinary claims of Sade’s sceptical powers justified? To answer this question, this paper sets out to identify the moral and meta- ethical claims made in Sade’s works, and to assess his arguments for those claims. (shrink)