The Marquis de Sade was the first modern atheist who openly declared in writing his willingness to push atheism to its logical conclusions. He certainly embraced the arguments put forth by Diderot, d’Holbach and their like, but he wasn’t willing to stop where they stopped. Rather he applied the wickedly cutting logic of passion to get to the heart of what a godless reality would be.
The other atheists of the 18th century insisted on maintaining a concept of universality even though they had rejected its basis. For them, there was a universal reason that all could come in time to understand, and thus a universal moral order (even if it had freed itself from some of the more personal intrusive aspects – Diderot in particular had no use for the absurd and hypocritical sexual morality of his time) based on this reason. Sade recognized that a reality without god couldn’t possibly have a universal reason – there was no basis for it. Rather each of us has her own reasons, which Sade was convinced sprang from our passions.
Passion is the key to Sade’s concept of atheism. If he accepted the logic of the arguments of Diderot, d’Holbach and La Mettrie, this was because they agreed with the logic of the passions. And Sade, with a psychological perception far exceeding that of Kraft-Ebing, Freud, Havelock Ellis and their like, recognized that the passions were utterly singular (thus doing away completely with the concept of perversion – if each passion is unique, none can be any more or less perverse than any other) and that thus their logic, though quite rigorous, was like the passions specific to particular unique individuals. This does not mean that broader conclusions cannot be drawn from this logic; it simply means that those conclusions will mainly involve the undermining of all alleged universal values. If we are capable of imagining limitless variations of the passions, an infinity of desire, then there is no place for an infinite being who places limits on them. Such a being becomes an absurdity, simply an expression of the fear human beings have of the surging power of their own passions. This theme threads through all of the better known works of Sade, and is far more important to understanding his atheism than the rational arguments he puts into the mouths of his characters.
But it is precisely this which makes Sade frightening. This infinity of the passional imagination is an abyss into which Sade plunges us showing us the darkest possibilities of our own imaginations without offering us the safety nets that the sexologists and psychoanalysts offer with their identities grounded in the concepts of perversion or neurosis. Sade makes it very clear that these concepts are also attempts to deny the true singularity of passion which, for him, with the infinity it grants to the human imagination, is the greatest guarantee that there is no god, no infinite being capable of placing boundaries on the human mind.
But though Sade takes us into this abyss, he does not lead us out. For Sade, though we are each unique, with passions and proclivities that cannot be classified because they have no precise correspondence in anyone else, we remain slaves to these passions and proclivities. They are not so much ours as we are theirs. In this, Sade is very much a child of his age (though in a quite unique way). His atheism also tends toward a sort of determinism in which one cannot help but carry out the passions “nature” has given them. Though this does not undermine Sade's atheism, it does weaken it, in that it still leaves you and I stuck in the hands of things apparently greater, more powerful, than ourselves... If these seemingly greater things--our own unique passions and proclivities--do not need to be destroyed, they do need to be mastered and made our own. Otherwise the question remains open: have we really overcome all gods?