He explains to Eugénie that morality, compassion, religion, and modesty are all absurd notions that stand in the way of the sole aim of human existence: pleasure.

Their incest — and all manner of other sexual activity and taboos, such as sodomy, adultery, and homosexuality — is justified by Dolmancé in a series of energetic arguments that can ultimately be summarised by "if it feels good, do it".

The corruption of Eugénie is actually at the request of her father, who has sent her to Madame de Saint-Ange for the very purpose of having his daughter stripped of the morality that her virtuous mother taught her.

There is a lengthy section within the fifth dialogue titled "Yet Another Effort, Frenchmen, If You Would Become Republicans", in which the Marquis de Sade argued that having done away with the monarchy in the French Revolution, the people of France should take the final step towards liberty by abolishing religion too.

Know well that you cannot possibly liberate her from royal tyranny without at the same time breaking for her the fetters of religious superstition; the shackles of the one are too intimately linked to those of the other; let one of the two survive, and you cannot avoid falling subject to the other you have left intact.

Madame de Mistival is horrified to find that not only her husband arranged for their daughter's corruption but also Eugénie has already lost any moral standards that she previously possessed, along with any respect or obedience towards her mother.

Eugénie refuses to leave, and Madame de Mistival is soon stripped, beaten, whipped, and raped, her daughter taking an active part in this brutality and even declaring her wish to kill her mother.

Spanish director Jesús Franco has made two films based on Philosophy in the Bedroom: Eugenie… The Story of Her Journey into Perversion (1970)[5] and Eugenie (Historia de una perversión) (1980).