That, however, which first moves, not as that for the sake of which motion subsists, but as that whence the principle of motion is derived, exists together with that which is moved. I say together with, because nothing is between them; for this is common to every thing which is moved, and which moves. But, since there are three motions, viz. according to place, according to quantity, and according to quality, it is also necessary that the things which are moved should be three. The motion therefore according to place, is lation; that according to quality, alliation; and that according to quantity, increase and diminution. In the first place, therefore, let us speak concerning lation; for this is the first of motions. Whatever, therefore, is borne along, is either moved by itself, or by another. Hence, with respect to such things as are moved by themselves, it is evident that in these the mover and the thing moved subsist together; for that which first moves is inherent in them; so that there is nothing between. But it is necessary that such things as are moved by another, should be moved in a fourfold manner; for there are four species of lation which is produced by another, viz. drawing, impelling, carrying, rolling; since all the motions according to place are reduced to these: for impulsion is a certain pushing, since that which pushes any thing from itself, follows the thing which it pushes. But repulsion is when the mover does not follow by moving; and throwing is when the mover produces a more vehement motion by which he drives a thing from himself; than is prouced by the natural lation of that thing, and when the thing is moved as long as the motion retains its power. Again, propulsion and compulsion, are repulsion and drawing; for propulsion is repulsion; since it is a repulsion of a thing, either from itself, or from another. But compulsion is drawing; for it is a drawing of a thing to itself, and to another. So that whatever species there are of these motions, they ought to be referred to these, as, for instance, the thickening of a web (spathēsis) and weaving; for the former is compulsion, and the latter propulsion. In like manner other commixtures and separations are to be referred to these; for all of them will be propulsions, or compulsions; except such as are in generation and corruptions. At the same time too, it is evident that commixtures and separation are not any other genus of motion; for all of them are distributed into some of the above-mentioned motions. Farther still, inspiration is drawing; but expiration is pushing. In like manner also, excreation (ptusis), and such other motions as are produced through the body, by which any thing is expelled or assumed; for these are drawings, but those repulsions. But it is also necessary to refer the other motions according to place; for all of them fall into these four. Again, of these motions, carrying and rolling are referred to drawing and pushing; for carrying subsists according to some one of these three modes; for that which is carried is moved according to accident, because it is in that which is moved, or upon something that is moved; but that which carries is moved, either because it is pushed, or drawn, or rolled; so that carrying is common to all the three. But rolling is composed from drawing and pushing: for that which rolls must necessarily partly draw, and partly push; since it leads one part from itself, and another part to itself. Hence, if that which pushes, and that which draws, subsist together with that which is pushed and drawn; it is evident that there is nothing between that which is locally moved, and that which locally moves. This also is evident from definitions; for pushing is a motion either from a thing itself, or from something else to another. But drawing is the motion of a thing from another to itself, or to another, when the motion of that which draws is swifter and separates those things that are continuous: for thus the other is at the same time drawn. (But perhaps there may appear to be a certain drawing after another manner; for wood draws fire, not in this way. It is, however, of no consequence, whether that which draws is moved or abides; for sometimes it draws where it is, and sometimes where it was). But it is impossible for a thing to move something from itself to another, or from another to itself, when it does not touch it. Hence0, it is evident that there is nothing between that which is locally moved, and that which locally moves. Neither is there any thing between that which is changed according to quality, and that which changes it. But this is evident from induction; for in all things it happens, that what changes the extreme according to quality, and that which is first so changed, subsist together; since these are the passions of the subject quality: for we say, either that which is heated, or that which is sweetened, or that which is condensed, or that which is dried, or that which is whitened, is changed in quality; in a similar manner asserting this of the inanimate and the animated: and again, as well of the insensible parts of animals, as of the senses themselves: for the senses also are, in a certain respect, changed in quality; since sense which is in energy, is a motion through the body, sense being passively affected. With such things, therefore, as the inanimate is changed in quality, with these that which is animated is also so changed; but the inanimate is not changed in quality with all such things as that which is animated is changed; for they are not changed in quality according to the senses. And the one in being passively affected is latent, but the other is not latent. Nothing, however, hinders but that the animated nature may be latent, when the change in quality is not effected according to the senses. If, therefore, that which is changed in quality, is so changed by sensibles, it is evident that in all these that which changes the extreme in quality, and that which is first changed in quality, subsist together; for to that the air is continuous, and body to air. And again, colour is continuous to light, and light to the sight. Hearing also, and smelling, subsist after the same manner; for the air is the first mover with respect to that which is moved. And in like manner in the taste; for juice subsists together with the taste. The like also happens in things inanimate, and which are deprived of sense. So that nothing will subsist between that which is changed, and that which changes, according to quality. Neither is there any thing between that which is increased, and that which increases; for that which first increases, increases that which adheres to it, so as that the whole may become one. And again, that which is diminished, is diminished in consequence of something departing from that which is diminished. It is necessary, therefore, that there should be a continuity in that which increases and that which is diminished; but in things continued, there is nothing between. Hence, it is evident that nothing subsists between that which is moved, and that which moves, when they are first and last, with reference to that which is moved.
