motion--so that it shall in itself constitute a little working microcosm--appears to be the first condition to the being of a subjective personality. Why, then, does not the working of a machine present a subjective side? Our answer to this question is to be found in the following considerations. We are going upon the hypothesis that all mind is matter in motion, and that all matter in motion is mind--or, as Clifford phrased it, that all the external world is composed of mind-stuff. No matter how lightly we may shade _x_, we are assuming that it must be shaded, and not left perfectly white. Now, both mind and matter in motion admit of degrees: first as to quantity, next as to velocity, and lastly as to complexity. But the degrees of matter in motion are found, in point of observable fact, not to correspond with those of mind, save in the last particular of complexity, where there is unquestionably an evident correspondence. Therefore it is that a machine, although conforming to the prime condition of subjectivity in being a circumscribed system of matter in motion, nevertheless does not attain to subjectivity: the _x_ does not rise to _z_ because the internal processes of _x_ are not sufficiently intricate, or their intricacy is not of the appropriate kind. From which it follows that although, as I have said, all matter in motion is mind, merely as matter in motion (or irrespective of the kinds and degrees of both) it may not necessarily be mind in the elaborated form of consciousness: it may only be the raw material of mind--or, as Clifford called it, mind-stuff. Thus, although all conscious volition is matter in motion, it does not follow that all matter in motion is conscious volition. Which serves to restate the question as to how far it is probable, or improbable, that all matter in motion is conscious volition--i.e. how deeply we ought to shade _x_.