François Châtelet (1925-1985) was a political philosopher and a historian of philosophy. He was married to Noëlle Châtelet, the sister of Lionel Jospin, who served as the Prime Minister of France from 1997-2002 under President Jacques Chirac.
Châtelet helped establish the department of philosophy at the University of Paris, Vincennes, in 1969, along with Michel Foucault and Gilles Deleuze, and co-founded the Collège international de philosophie (International College of Philosophy). The Vincennes campus was moved to Saint-Denis in 1980, and Deleuze and Châtelet were close colleagues in the department until the latter's death in 1985. Châtelet participated in several of Deleuze's seminars, including a presentation on Kant in the session of 21 March 1978.
Châtelet was diagnosed with lung cancer, caused by smoking, in 1982. He had a tracheotomy and remained confined to his house for the last two years of his life, bound to his oxygen machines. In 1982, Deleuze sent him a letter: "I often think of you at Evreux. After all, you are living proof of the existence of the soul, which is how you held on when your body gave way. I was struck how when you were suffering the worst you stayed so like your usual self: it was the only sign you could give us. You are a marvelous man....May you recover quickly. The different stages of your treatment, your convalescence, your invention of a new way of life, which will keep you safer, you will be able to manage all of that. It started with Normandy, but it also resembles an incredible interior voyage" (citied in François Dosse, Intersecting Lives, 351). Deleuze and his wife Fanny visited Châtelet almost every Sunday during the last two years of his life.
Châtelet's death seemed to have affected Deleuze. Deleuze's friend Jean-Jacques Lebel later recollected that Deleuze "wrote me a letter two weeks before his suicide in very shaky handwriting to tell me that he didn't want to live through what François had lived through" (Dosse, Intersecting Lives, 497)
Châtelet's books include Périclès et son siècle (Pericles and His Century), 1960; Platon (Plato), 1965; Hegel (Hegel), 1968; La philosophie des Professeurs (The Philosophy of Professors), 1970; Une histoire de la raison (A History of Reason), 1972. Châtelet's memoir, Les années de démolition (Paris: Hallier, 1975), was greatly admired by Deleuze. Châtelet also edited the eight-volume Histoire de la philosophie (History of Philosophy) (1972–1973). Deleuze's article "How to Recognize Structuralism?" (A quoi reconnait-on le structuralisme?") was included in the last volume in the series, Le XXème siècle (The Twentieth Century).
In 1988, after Châtelet's death, Deleuze published a short study on his work, Pericles et verdi: la philosophie de François Châtelet (Paris: Minuit, 1988)