Lecture 7 — What things are in place simply

If, then, a body has another body outside it and containing it, it is in place, and if not [thus contained], [then] not.

That is why, even if there were to be water that had not a container, the parts of it, on the one hand, will be moved (for one part is contained in another), while, on the other hand, the whole will be moved in one sense but not in another.

For as a whole, it does not simultaneously change its place, though it will be moved in a circle. For this place is the place of its parts. (Some things are moved not up and down, but in a circle; others up and down—namely, such things as admit of condensation and rarefaction.)

As was explained, some things are potentially in place, others actually. So, when you have a homogeneous substance that is continuous, the parts are potentially in place; when the parts are separated but in contact, like a heap, they are actually in place.

Again, some things are in place per se—every body that is movable either by way of locomotion or by way of increase is per se somewhere—but the heavens, as has been said, are not anywhere as a whole, nor in any place, if at least, as we must suppose, no body contains it. On the line on which it is moved, its parts have place: for each is contiguous to the next.

But other things are in place indirectly, through something conjoined with them, as the soul and the heavens. The latter is, in a way, in place, for all its parts are; for on the orb, one part contains another.

That is why the upper part is moved in a circle, while the all is not anywhere. For what is somewhere is itself something, and there must be alongside it some other thing wherein it is and that contains it. But, alongside the all or the whole, there is nothing outside the all, and for this reason, all things are in the heavens; for the heavens, we may probably say, are the all.

Yet their place is not the same as the heavens. It is part of it, the innermost part of it, that is in contact with the movable body, and for this reason, the earth is in water, and this in the air, and the air in the ether, and the ether in heaven—but we cannot go on and say that the heavens are in anything else.

472. After defining place, the Philosopher now shows how something exists in place.

About this, he does two things:

first, he shows how something is absolutely in place and how not;

second, he shows how a thing not absolutely in place is in place in a certain respect, at that is why (212a32; [481]).

473. Therefore, he first (212a31) concludes from the foregoing (Lect. 6, nn. 470–71.) that, since place is the boundary of the container, whenever a body has another body outside it and containing it, it is in place absolutely and per se. But, if such a body does not have an external body containing it, it is not in place at all. The only body in the universe that exemplifies this second case is the outermost sphere, whatever it may be. Hence, according to this definition, it follows that the outermost orb is not in place.

474. But this seems to be impossible, because the outermost sphere is in motion in place, and nothing is moved in place unless it is in place.

Now this difficulty does not arise for those who hold the opinion that space is place. For they are not forced to say that, in order to be in place, the outermost sphere must have a body containing it. Rather, the space penetrating the entire universe and all its parts is the place of the entire universe and of each of its parts, according to these philosophers. But this position is impossible, for one must admit either that place is not distinct from the thing in place or that space has dimensions existing per se but yet penetrating the dimensions of sensible bodies—both of which positions are impossible.

475. Therefore, Alexander said that the outermost orb is not in place at all, for it is not necessary for every body to be in place, since place is not in the definition of body. For this reason, he held that the outermost sphere is not in motion in place, neither as a whole nor as to its parts.

But, since every motion must fit into one of the genera of motion, Avicenna, following him, said that the motion of the outermost sphere is not motion in place, but motion in position. This is against Aristotle, who says in book 5 that motion is present only in three genera: quality, quantity, and place. (Lect. 4.)

Avicenna’s position is untenable because it is impossible that motion strictly speaking be in a genus the account of whose species consists in an indivisible. For the reason why there is not motion in the genus “substance” is that the account of every species of substance consists in an indivisible, due to the fact that the species of substances do not admit of more or less.

On this account, since motion is successive, a substantial form is not made existent by motion, but by generation, which is the terminus of motion. The case is different with whiteness and like things, which can be participated according to more or less. But every species of position has an account that consists in an indivisible, such that, if anything be added or taken away, the original species does not remain. Hence, it is impossible for motion to exist in the genus of position.

Besides, the same difficulty remains. For position taken as a predicament implies the order of parts in place, but if it be taken as a difference in the genus of quantity, it implies merely an order of parts in a whole. Therefore, whatever is moved according to position must be moved according to place.

476. Others, such as Avempace, said that place should be assigned in one way to a body moving in a circle and in another way to a body moving in a straight line. For since a straight line is imperfect, since it can be added to, a body moving in a straight line requires a place externally containing it, but because a circular line is perfect within itself, a body moving in a circle does not require an external place to contain it, but merely a place about which it may revolve; hence it is that circular motion is said to be motion about a center. So, therefore, they say that the convex surface of the sphere contained is the place of the first sphere. But this is against the common suppositions about place already laid down—namely, that place is a container, and that it is equal to the thing in place. (Lect. 5, n. 446.)

477. And therefore Averroes said that the outermost sphere is in place per accidens. To understand this, one should consider that everything that has fixity by means of something else is said to be in place per accidens, due to the fact that that by means of which it is fixed is in place, as is evident in the cases of a nail fixed in a ship and of a man at rest in a ship. Now, it is clear that bodies moving rotationally are fixed, because their center is immobile; hence, the outermost sphere is said to be in place per accidens insofar as the center about which it is revolving has existence in place. The fact that the lower spheres have a per se place in which they are contained is accidental and not essential to a body moving rotationally.

But, against this, it is objected that, if the outermost sphere is in place per accidens, then it is in motion in place per accidens, and so per accidens motion is prior to per se motion. To this, the answer is given that, for rotational motion it is not necessary for a body moving per se rotationally to be in place per se, although it is necessary for straight line motion.

But this seems to be against Aristotle’s definition, given above, of what is in place per accidens. (Lect. 5, n. 450.) For he said that some things exist or are moved in place per accidens because that in which they exist is in motion. But nothing is said to be in place per accidens because something entirely outside it is in place. Now, since the center is completely extrinsic to the outermost sphere, it seems ridiculous to say that the outermost sphere is in place per accidens because the center is in place.

478. And, therefore, I favor more the opinion of Themistius, who said that the outermost sphere is in place by means of its parts. To understand this, it must be recalled that Aristotle said above (Lect. 5, n. 449.) that there would be no discussion about place except for the act of motion, which reveals the existence of place from the fact that bodies succeed one another in the same place. Hence, although place is not of the essence of body, yet it is necessary for a body moved according to place. In the case of a body moving locally, the reason it is necessary to assign a place is that, in that motion, a succession of diverse bodies in the same place is considered. Therefore, in the case of bodies moving in a straight line, it is clear that one body succeeds another in the same place according to their totality, for one whole body leaves one whole place, which is then occupied by another whole body. Hence, a body that is in motion in a straight line must be in place in its entirety.

But, in the case of rotational motion, although the whole body comes to be in different places as distinguished by reason, nevertheless the whole body does not change its place as to subject: for the place remains ever the same as to subject, but varies only according to reason, as will be said in book 6. (Lect. 2.) Nevertheless, the parts change place not only as to reason, but as to subject also. Therefore, in the case of rotational motion, there is not a succession of whole bodies in the same place, but of parts of the same body. Therefore, a rotating body does not essentially require a place according to its totality, but according to its parts.

479. But, against this, there seems to be the objection that the parts of a continuous body are neither in place nor moved in respect to place; rather, it is the whole that is both moved and in place. But it is clear that the outermost sphere is a continuous body; therefore, its parts are neither in place nor in motion in place. Consequently, it does not seem to be true that place should be attributed to the outermost sphere by reason of its parts.

The answer to this objection is that, although the parts of a continuous body are not actually in place, they are so potentially, insofar as the continuum is divisible. For a part, if it is separated, will be in the whole as in a place; hence, in this manner, the parts of a continuum are moved in place.

This is clearly evident in liquid continua that are easy to divide—for example, in the case of water, whose parts are found to be in motion within the whole water.

Consequently, because something is said of a whole by reason of its parts insofar as the parts of the outermost sphere are potentially in place, the entire outermost sphere is in place per accidens by reason of its parts; to be in place in that way is enough for rotational motion.

480. If a further objection is raised that what is in act is prior to what is in potency, and that consequently it seems improper that the first local motion be that of a body existing in place by means of its parts, which are potentially in place, the reply is that this is most fitting to the first motion. For it is necessary that the descent from the one immobile being to the diversity that is found in mobile things be made step by step. Now the variation based on parts existing in place potentially is less than that of wholes existing in place actually. Hence, the first motion, which is rotational, has less deformity and retains greater uniformity by being closer to the immobile substances. Now, it is much better to say that the outermost sphere is in place on account of its intrinsic parts, rather than on account of the center, which is entirely extrinsic to its substance. This is also more in agreement with Aristotle’s opinion, as is clear if one considers the passage following, in which Aristotle shows how the heavens are in place, at that is why (212a32).

481. For in regard to this, he does two things:

first, he shows how the outermost sphere is in place;

second, he draws a conclusion from what has been said, at that is why the upper part (212b13; [485]).

About the first, he does three things:

first, he shows that the outermost sphere is in place through its parts;

second, he shows how its parts are in place, at as was explained (212b3; [483]);

third, he shows how the parts make the whole to be in place, at again, some things are (212b7; [484]).

482. Therefore, because he had said that, if a body does not have something outside of it containing it, it is not in place per se, he concludes (212a32) that, if a body of this kind, such as the outermost sphere, be water (which will more easily illustrate what we are about to say on account of its easy divisibility), its parts will be in motion inasmuch as one part contains another, thus making it exist in place after a fashion.

But the entire water will be in motion in one sense and in another sense not. For it will not be in motion in such a way that the entire water will change its place as though being transferred to another place distinct as to subject, but it will be moved rotationally—a motion that requires place for the parts and not for the whole. And it will be moved not up and down, but circularly, for some things are moved up and down and change place in their entirety, namely, rare and dense bodies, or light and heavy things.

483. Then, at as was explained (212b3), he indicates how the parts of the outermost sphere exist in place, saying that, as was mentioned above, some things are actually in place, others potentially. Hence, in the case of a continuum of similar parts, the parts are in place potentially, as in the case of the outermost sphere; but when the parts are separated and merely contiguous, as occurs in a pile of stones, the parts are in place actually.

484. Then, at again, some things are (212b7), he shows how it follows from this that the entire sphere is in place. And he says that some things are per se in place—as any body that is per se in motion in place, whether it be in respect to local motion or increase, as was said above. (Lect. 5, n. 450.) But the heavens, namely, the outermost sphere, are not in place in this manner, as was said, since no body contains them; but inasmuch as they are moved rotationally, with part succeeding part, place is attributed to the parts potentially, as was said, inasmuch as one part is contiguous to—that is, is consecutive to—another. (Cf. bk. 5, lect. 5.)

Certain things, indeed, are in place per accidens, such as the soul and all forms; in this manner, the heaven, or the outermost sphere, is in place insofar as all its parts are in place, since each of its parts is contained under another in the rotation of the sphere. For in a non-round body, the outermost part remains uncontained and merely containing, but in a round body each part is both container and contained, although potentially. Hence, it is by reason of all its parts that a round body is in place. And this Aristotle takes to be per accidens, namely, what is true of the parts, as above when he said that the parts of a body are in motion per accidens in place. (Lect. 5, n. 450.)

485. Then, at that is why the upper part (212b13), he draws a conclusion from the foregoing. For since he had said that a body in rotational motion need not be in place in its entirety but only per accidens by reason of its parts, he concludes that the outermost body is moved only rotationally, because the whole in question is not anywhere. What is somewhere is itself something and has something outside of it by which it is contained; but there is nothing outside the whole. For this reason, all things are said to be in the heavens as in the outermost container, because the heavens are probably the containing whole.

He says probably because it has not yet been proved that there is nothing outside the heavens. It is not to be thought that the very body of the heavens is a place; rather, it is a certain final surface of it turned toward us, which is as a boundary in contact with the mobile bodies existing in it. For this reason, we say that earth is in water, which is in air, which is in ether, that is, fire, which is in the heavens, which are not in anything else.

486. However, according to the intention of Aristotle, this passage must be explained differently. For the example of water that he first adduced is not to be referred, according to him, to the outermost sphere only, but to the entire universe, which indeed is moved insofar as its parts are moved: some rotationally, as are the heavenly bodies; some up and down, as are the lower bodies. As to what he said later on, that some things are in place actually and other potentially, this is not to be referred to what he said previously, but is to be taken independently. For since he had said that some things are in place according to their parts and others according to their totality, he adds afterward that some things are in place according to act and others according to potency. Finally, he says that some things are in place per se and others per accidens.

In this connection, note that, according to Aristotle, “the heavens” are to be taken in two senses here:

first, they are taken for the entire universe of bodies, and especially of the heavenly;

second, for the outermost sphere.

He says, therefore, that those things are in place per se that are in motion according to place, whether they are in motion according to their totality or according to their parts, as are the heavens, that is, the universe; in place per accidens are the soul and the heavens, that is, the outermost sphere. For it is necessary to say that all the parts of the universe are somehow in place: the outermost sphere per accidens and other bodies per se, inasmuch as they are contained by a body outside of them. And he manifests this up to the end.