Jean-Jacques Rousseau's search for the realities that underlie the 'signe exterieur' may not seem very far from the inner quest Diderot describes in works like the Elements de physiologie. But there is an important distinction, and one which gives its uniquely subjective quality to Rousseau's writing. His concern is with the way a datum appears to and is construed by the subjective self, not the 'homme-machine' that functions indistinguishably from other such organisms in terms of the mechanics of perception. He criticizes his contemporaries for their preoccupation with what is for him an empty thing, the residue deposited after memory and association have worked their effect, and which in their eyes constitutes certain reality. One of Rousseau's memories dating from the period before Bossey, where he lived with the Lamberciers, touches on a theme dear to his heart. At times Rousseau argues the unalterable facts of his character in a manner that seems deliberately provocative to his reader.