But what is the source of this strength that leaves us fearless before the source of fear, dismayed before the source of dismay? From what power does joy suddenly find that strength which enables it to resist the corrosive effect of a tragedy to which it is exposed? Such is the essential question to which we must finally propose an answer. This is what a barely 21-year-old Clement Rosset reports the experience and analysis of in this unpublished essay, which prefigures in an original way many of his later reflections, and in particular this one: the impossibility of giving a reason for the tragic, lucid joy of existence. Clement Rosset (Carteret, 1939) taught philosophy from 1967 to 1998 at the Faculty of Nice. Among his main works: The major force (1983), The Real and its double, essay about illusion (1976), Logic of the worst (PUF, 2008). His Absence as prodigy was published by The Belles Lettres in 2017, as well as Where Paradise is (2018). Santiago Espinosa (Mexico City, 1978) is a philosopher and translator. He is the 2015 recipient of the CNL’s Cioran Fellowship. Encre Marine has already published from him The inexpressive musical (2013), To see and to hear (2016), Methodology of appearances (2017) and The Unthought (2019). Mais quelle est la source de cette force qui nous laisse sans peur devant la source de la peur, sans desarroi devant la source du desarroi ? A quelle puissance la joie trouve-t-elle soudain cette force qui lui permet de resister a l'effet corrosif d'une tragedie a laquelle elle s'expose ? Telle est la question essentielle a laquelle nous devons enfin proposer une reponse. Voici ce dont un Clement Rosset d'a peine 21 ans rapporte l'experience et l'analyse dans cet essai inedit qui prefigure de maniere originale bon nombre de ses reflexions ulterieures, et notamment celle-ci: l'impossibilite de rendre raison de la joie tragique, lucide d'exister.