already accepted the other. For if you suppose that the qualities of things are nothing but inextensive sensations affecting a consciousness, so that these qualities represent merely, as so many symbols, homogeneous and calculable changes going on in space, you must imagine between these sensations and these changes an incomprehensible correspondence. On the contrary, as soon as you give up establishing between them a priori this factitious contrariety, you see the barriers which seemed to separate them fall one after another. First, it is not true that consciousness, turned round on itself, is confronted with a merely internal procession of inextensive perceptions. It is inside the very things perceived that you put back pure perception, and the first obstacle is thus removed. You are confronted with a second, it is true: the homogeneous and calculable changes on which science works seem to belong to multiple and independent elements, such as atoms, of which these changes appear as mere accidents, and this multiplicity comes in between the perception and its object. But if the division of the extended is purely relative to our possible action upon it, the idea of independent corpuscles is a fortiori schematic and provisional. Science itself, moreover, allows us to discard it; and so the second barrier falls. A last interval remains to be over-leapt: that which separates the heterogeneity of qualities from the apparent homogeneity of movements that
