"Now as to thought," says Leibniz in a famous passage in the Preface to the New Essays, "it is certain ‖ that it could not be an intelligible modification of matter or one that could be comprised therein and explained; that is to say, that the feeling or thinking being is not a mechanical thing like a clock or a mill." And, indeed, if one were to enter such a machine, one would find but "sizes, figures, and motions"¹ but nothing that resembles a consciousness.