The essential core round which loves that have been lived through make and unmake their halo, that mysterious human being, loved in spite of himself and ourself, interchangeable and yet unchanging; scrutinized as though everything depended on what he is in himself and yet accidental, always the victim of doubt, that doubt which whispers in our ear that any being would have replaced him, if chance had disposed of him and us differently--has this essential core an existence of its own, or does its existence come from an illusion whose seat is inside us?