But it is not (usually) the ideas of philosophers that change reality; nor, conversely, is it the practice of ordinary people. What changes history, what kindles revolutions, is the meeting of the two. A lofty mind — that of the Abbe de l’Epee — had to meet a humble usage — the indigenous sign language of the poor deaf who roamed Paris — in order to make possible a momentous transformation. If we ask why this meeting had not occurred before, it has something to do with the vocation of the Abbe, who could not bear to think of the souls of the deaf-mute living and dying unshriven,