In The Ethics of Psychoanalysis Lacan says: “So as to produce the kind of shock or eye-opening effect that seems to me necessary if we are to make progress, I simply want to draw your attention to this: if The Critique of Practical Reason appeared in 1788, seven years after the first edition of The Critique of Pure Reason there is another work which came out six years [!] afterThe Critique of Practical Reason a little after Thermidor in 1795, and which is calledPhilosophy in the Boudoir” (78). What is supposed to produce the shock effect is not the simple juxtaposition of dates, of course, but the implicitly Hegelian reading of history which makes those dates significant, and which comes out in full strength when Lacan says, in Kant avec Sade: “The Philosophy in the Boudoir comes eight years [!] after the Critique of Practical Reason. If, after seeing that the former agrees with the latter, we prove that it completes it, we will say that it gives the truth of the Critique” (Ecrits II 120; my translation). Lacan’s “proof,” however, is anything but rigorous or systematic; so his provocative statement will probably sound inspiring to Lacan enthusiasts and gratuitous to virtually anyone else. Which is a pity, because the statement is absolutely correct: it is indeed the case that Sade brought to their extreme consequences the characteristic premisses of Kant’s ethics, thus unfolding their truth in ways which the man Kant might even have vehemently resisted, but which were nonetheless necessary. Here I would like to provide more of a systematic and rigorous defense of this statement, though I make no claim as to how faithful my reconstruction might be to Lacan’s “intentions” (the irrelevance of this issue from the point of view espoused here will soon become apparent; hence it will also become apparent that it is an issue this point of view need not be concerned with).