There are writers you do not so much read as live alongside: writers of a depth, a density, a multiplicity of suggestions that resist the sort of encapsulation by which their names wither into the occasion for empty allusions and knowing nods. For nearly twenty years now, the French philosopher Vladimir Jankélévitch has been such a writer for me. I know of few accounts more moving of the tragedy of the human condition than his The Irreversible and Nostalgia. His Pure and Impure has aided me in keeping my distance from many petty fanaticisms fashionable at present. He reminds me that “philosophy is not the construction of a system, but the resolution to look naively in and around oneself,” that the first sincere impulse toward knowledge is the patient articulation of one’s ignorance.