Both Diderot and Rousseau, in different ways, had dissented from the rationalism of their times, deploring its narrow concern with 'scientific' knowledge at the expense of inner conviction. Rousseau championed sensibility and the rule of the heart, and throughout his writings Diderot argued the claims of independent thought and the autonomous self: despite his attraction to the philosophy of materialism, he was always drawn by the force of what could not be physically accounted for or rationally deduced. Constant himself used memory as confirmation rather than revelation. He needed a record of the past, he wrote, not to induce the same sensations as actual experience had provoked, but simply to remind himself that he had once felt them. It is precisely because Proust, like Rousseau and Montaigne, sees the self as essentially unfixed and unstable that he can embrace the project of situating it by joining up 'temps perdu' with the present.