Since, however, not only motion but rest seems to be contrary to motion, this must be determined: for motion is simply contrary to motion; but rest is also opposed; for it is privation; and privation, in a certain respect, is said to be contrary. But what kind to what kind? For instance, is local rest contrary to local motion? But this is now simply asserted: for whether is the motion which is from this, or the motion which is to this, opposed to the permanency which is in this? But it is evident, since motion is in two subjects, that the permanency which is in this, is opposed to the motion which is from this to a contrary; and that the permanency, which is in a contrary, is opposed to the motion which is from a contrary into this. At the same time, however, these permanencies or abidings are contrary to each other: for it would be absurd if motions are contrary, that the rests opposed to them should not also be contrary. But these rests and motions are in contrary terms. Thus, the rest which is in health, is opposed to the rest which is in disease, and to the motion from health to disease: for it is irrational to suppose that this rest is contrary to the motion which is from disease to health: for the motion to that in which it was established is rather a resting, so far as it happens to be at the same time produced with motion. But it is necessary, that either this or that should take place: for the rest which is in whiteness, is not contrary to the rest which is in healths. But of such things as have not contraries, the mutation is indeed opposite, viz., the mutation from same to the mutation to the same; but the motion is not. Thus, the mutation from being is opposite to the mutation into being; and there is not a permanency of these, but immobility. And, if, indeed, non-being were a certain subject, the immobility which is in being, would be contrary to that which is in non-being. But if non-being is not any thing, it may be doubted to what the immobility in being is contrary, and if it is rest. If, however, it be, either not all rest is contrary to motion, or generation and corruption will be motion. It is evident, therefore, that it must not be caJled rest, unless these also are called motions; but it must be denominated something similar, and immutability. But it is contrary, either to nothing, or to that privation of mutation which is in non-being, or to corruption: for this is from that; but generation into that.
