LECTURE 5 (210 b 33-211 b 4)

CERTAIN THINGS NECESSARY TO INVESTIGATE THE DEFINITION OF PLACE ARE SET FORTH

             445. After the foregoing disputation as to whether place is and what it is, and after certain doubts have been answered, he here begins to determine the truth concerning place.

             First he sets forth certain suppositions about place which he will use in treating place. Secondly, where he says, 'We ought to try . . .' (211 a 7), he shows how the definition of place ought to be given. Thirdly, where he says, 'First then we must . . .' (211 a 12), he begins to treat place.

             446. He says, therefore, first that what place is will become clear from what follows. It is necessary first to accept certain suppositions, as it were, and principles known per se, that is, those things which seem to belong to place per se.

             There are four of these.

             All men consider this to be worthwhile: first that place contains that of which it is the place, but nevertheless place is not part of that which is located in place. He says this to exclude the way in which form contains. For the form is part of the thing and contains in a different way than place.

             The second supposition is that primary place, that is, that in which a thing is primarily, is equal to that which is located in place, and is neither greater nor smaller.

             The third supposition is that place is not absent from anything that is located. Thus everything that is located has place. Nevertheless, this does not mean that one and the same place is never removed from some one thing that is located, because place is separable from that which is located. But when one place is removed from something that is located, then that which is located comes to be in another place.

             The fourth supposition is that upwards and downwards is found in all place as its differentia. Further each body which is outside its proper place is naturally carried to it, and when it is in it, it remains in it. Moreover, upwards and downwards are the proper places of natural bodies to which they are naturally moved and in which they remain. He says this in accordance with the opinion of those who do not posit any body beyond the nature of the four elements. For he has not yet proven that a celestial body is neither light nor heavy. But he will prove this later in De Caelo, I. Now from these suppositions he proceeds to the consideration of other things.

             447. Next where he says, 'We ought to try . . .' (211 a 7), he shows how the definition of place ought to be given.

             He says that in defining place our attention should be directed to the four things which are required for a perfect definition.

             First that it be shown what place is, for a definition is a statement indicating what a thing is.

             Secondly that certain objections concerning place be answered, for knowledge of the truth is the solution of difficulties.

             Thirdly that from the given definition the properties which are present in place be made clear, for the definition is the middle term in demonstration by which proper accidents are demonstrated of their subjects.

             Fourthly that from the definition of place the reason why some have disagreed about place will be made clear, and the reason for all the objections concerning place will be made clear. In this way each thing is defined most perfectly.

             448. Next where he says, 'First then we must . . .' (211 a 12), he treats place.

             First he shows what place is. Secondly, where he says, 'It is clear, too . . .' (212 b 23), he answers the difficulties that were previously raised. Thirdly, where he says, 'Also it is reasonable . . .' (212 b 29), he establishes the cause of the natural properties of place.

             Concerning the first part he makes two points. First he shows what place is, and secondly, how something is in place, where he says, 'If then a body . . .' (212 a 32).

             Concerning the first part he makes two points. First he sets forth certain things which are necessary to investigate the definition of place. Secondly, where he says, 'It will now be plain . . .' (211 b 5), he begins to investigate the definition of place.

             449. Concerning the first part he sets forth four things. The first of these is that there would have never been any inquiry about place if there were no motion in respect to place. For it was necessary to posit that place is different from that which is located in place, because two bodies are found successively in the same place, and likewise one body is found in two places. In the same way the transmutation of forms in one matter led to a knowledge of matter. And because the heavens are always moved some think that the heavens are in place. But some motions are motions in respect to place per se, that is, local motion, while other motions are motions in respect to place per accidens, that is, increase and diminution. For when quantity is increased or decreased, the body takes on a larger or smaller place.

             450. He gives the second point where he says, 'Again, when we say . . .' (211 a 18). He says that some things are moved per se and actually, for example, any body, while other things are moved per accidens. This happens in two ways.

             Some things which can be moved per se are moved per accidens. Thus the parts of a body, while they are in the whole, are moved per accidens, but when they are separated they are moved per se. For example, a nail when fixed in a ship is moved per accidens, but when it is freed from the ship it is moved per se.

             Other things cannot be moved per se, but are always moved per accidens. For example, whiteness and science change in place insofar as that in which they are is changed.

             He brings this up because in this way something per se or per accidens is constituted as being actually or potentially in place, and thus to be moved.

             451. He gives the third point where he says, 'We say that a thing . . .' (211 a 24). He says that one is said to be in the heavens as in a place because he is in the air which is in the heavens. Nevertheless, we do not say that one is primarily and per se in all air. Rather one is said to be in the air because of the last extremity of the air which contains him. For if all air were the place of something, for example, a man, then the place and that which is located in the place would not be equal, which is contrary to the supposition given above. But that in which something is primarily seems to be the extremity of the containing body, and in this way it is equal.

             452. He gives the fourth point where he says, 'When what surrounds, then . . .' (211 a 29).

             First he states the point and secondly he proves it, where he says, 'Further, if one body . . .' (211 a 34).

             He says, therefore, first that when the container is not divided from that which is contained, but is continuous with it, then the contained is not said to be in the container as in a place, but as a part is in a whole. For example, let us say that one part of air is contained by all air. He concludes this from the foregoing, for where there is a continuum there is no extremity in act, which he said above was required for place. But when the container is divided from and contiguous to that which is contained, then that which is contained is in place, existing in the extremity of the container primarily and per se. And the container, which is not part of the thing, is neither larger nor smaller in size, but equal. He explains how the container and that which is contained can be equal by the fact that the extremities of things which are contiguous exist together. Hence their extremities must be equal.

             453. Next where he says, 'Further, if one body . . .' (211 a 34), he proves this fourth point with two arguments.

             The first argument is that, if that which is contained is continuous with the container, then it is not moved in the container but together with it, as a part is moved together with the whole. But when that which is contained is divided from the container, then it can be moved in it, whether the container is moved or not. For a man is moved in a ship whether the ship is at rest or in motion. Therefore, since things are moved in place, it follows that place is a divided container.

             454. He gives the second argument where he says, 'Again, when it is not separate . . .' (211 b 1).

             He says that when that which is contained is not divided from the container but is continuous with it, then it is said to be in it as a part is in a whole. Thus sight is in the eye as a formal part, and the hand is in the body as an organic part. But when that which is contained is divided from the container, then it is said to be in it as in a vase, like water is in a jar and wine is in a cup. The difference between these is that the hand is moved with the body, but not in the body, while the water is moved in the jar. Therefore, since it was said above that being in place is like being in a vase, and not as a part in a whole, it follows that place is like a divided container.