If, therefore, the categories are divided by essence or substance, quality, the where, relation, and quantity, action and passion; it is necessary that there should be three motions, that which is of quantity, that which is of quality, and that which is according to place. But there is not motion according to essence, because nothing among beings is contrary to essence. Neither is there motion in relation because it is possible that one of the relatives being changed, the other may be truly predicated, though in no respect changed; so that the motion of these is according to accident. Neither, therefore, is motion of agent and patient, nor of any thing moved and moving, because there is not motion of motion, nor generation of generation, nor in short, mutation of mutation. For, in the first place, there may be a motion of motion in a twofold respect. Either as of a subject; as for instance, a man is moved, because he is changed from white into black. Is motion, therefore, thus heated or refrigerated, or does it change its place, or is it increased, or diminished? But this is impossible; because mutation is not any subject. Or there may be a motion of motion, because some other subject is changed from the mutation into another form; as for instance, a man from disease into health. But neither is this possible, except according to accident: for this motion is a mutation from one form into another; and in a similar manner generation and corruption; except that these mutations are thus into opposites, but this is not the case with motion. At the same time, therefore, he is changed from health into disease, and from this very mutation into another. It is manifest, however, that when he is diseased, be will now have been changed into a certain disease; for he may rest., or remain in that disease. Besides, he who is moved to disease, is not always moved to any casual motion, and that from some one to some other. So that the motion will be opposite, viz. the becoming well; but this, because it so happened; just as if from reminiscence he should be changed into oblivion, because that in which these are inherent is changed, at one time into science, and at another into health. Farther still, there would be a progression to infinity, if there should be a mutation of mutation, and generation of generation. It is necessary, therefore, that the former should be, if the latter will be. Thus, if simple generation should at any time be generated, that also which is generated will be generated. Hence that which was simply generated was not yet, but there was something which was generated, and which is now generated, and this again was once generated. Hence, that which was then generated was not yet. Since, however, there is not any thing first in infinites, there will not be that which was first generated; so that neither will that be which is consequent to this. Neither, therefore, is it possible for any thing to be generated, or moved, or changed. Again, contrary motion is of the same thing; and likewise rest, generation and corruption. Hence, that which is generated, is then corrupted when it becomes that which is generated: for neither immediately when it is generated is it then corrupted, nor afterwards; since it is necessary that what is corrupted should have a subsistence. Farther still, it is necessary that matter should subsist under that which is in generation or becoming to be, and under that which is changing. What then will it be? As that which is changed in quality, is either body or soul, so that which is becoming to be, is either motion or generation. And again, what is that into which it is moved? For it is necessary that there should be motion and generation of this, from this into this. At the same time, however, how will it be? for the generation of discipline will not be discipline; so that neither will there be generation of generation, nor a certain generation of a certain generation. Again, if there are three species of motion, it is necessary that some one of these should be the subject nature, and to which they are moved. Thus, it is necessary that lation should be changed in quality, or borne along. In short, since every thing which is moved, is moved in three ways, viz. either according to accident, or according to a part, or from itself, mutation can alone be changed according to accident; as if he who is restored to health should run, or learn. Mutation, however, according to accident, we have already omitted. But, since motion neither belongs to substance or essence, nor to relation, nor to action and passion; it remains, that it alone subsists according to quality, quantity, and situation: for in each of these there is contrariety. Let, therefore, the motion which subsists according to quality be alliation; for this common name is adapted to it. But I mean by quality, not that which is in essence; for difference also is quality, but that which is passive, according to which it is said to suffer, or to be impassive. But tne motion according to quantity, with respect to a common name is anonymous; but when it is divided into two species, it is increase, and diminution; the increase which tends to the perfect being magnitude: but that which is from this, diminution. And the motion according to place, with respect to the peculiar and the common, is anonymous; but let it be called, in common, lation; though those things alone are properly said to be borne along, which, when they change their place, cannot of themselves stop, and which do not move themselves according to place. But the change to the more and the less in the same form is alliation: for motion is from the contrary to the contrary, either simply, or in a certain respect: for the alliation which proceeds to the less is said to be changed into the contrary, but that which proceeds to the more, is moved as from the contrary to it. But it is of no consequence, whether it is in a certain respect changed, or simply; except that it is necessary that the terms should be contrary. But it is more and less, because more or less of the contrary is inherent, and is not inherent. That there are these three motions alone therefore, is from these things manifest.
