Summa Theologica, by St. Thomas Aquinas, , at sacred-texts.com
We must next consider the local movement of the angels; under which heading there are three points of inquiry:
(1) Whether an angel can be moved locally.
(2) Whether in passing from place to place he passes through intervening space?
(3) Whether the angel's movement is in time or instantaneous?
Objection 1: It seems that an angel cannot be moved locally. For, as the Philosopher proves (Phys. vi, text 32,86) "nothing which is devoid of parts is moved"; because, while it is in the term "wherefrom," it is not moved; nor while it is in the term "whereto," for it is then already moved; consequently it remains that everything which is moved, while it is being moved, is partly in the term "wherefrom" and partly in the term "whereto." But an angel is without parts. Therefore an angel cannot be moved locally.
Objection 2: Further, movement is "the act of an imperfect being," as the Philosopher says (Phys. iii, text 14). But a beatified angel is not imperfect. Consequently a beatified angel is not moved locally.
Objection 3: Further, movement is simply because of want. But the holy angels have no want. Therefore the holy angels are not moved locally.
On the contrary, It is the same thing for a beatified angel to be moved as for a beatified soul to be moved. But it must necessarily be said that a blessed soul is moved locally, because it is an article of faith that Christ's soul descended into Hell. Therefore a beatified angel is moved locally.
I answer that, A beatified angel can be moved locally. As, however, to be in a place belongs equivocally to a body and to an angel, so likewise does local movement. For a body is in a place in so far as it is contained under the place, and is commensurate with the place. Hence it is necessary for local movement of a body to be commensurate with the place, and according to its exigency. Hence it is that the continuity of movement is according to the continuity of magnitude; and according to priority and posteriority of local movement, as the Philosopher says (Phys. iv, text 99). But an angel is not in a place as commensurate and contained, but rather as containing it. Hence it is not necessary for the local movement of an angel to be commensurate with the place, nor for it to be according to the exigency of the place, so as to have continuity therefrom; but it is a non-continuous movement. For since the angel is in a place only by virtual contact, as was said above (Q, A), it follows necessarily that the movement of an angel in a place is nothing else than the various contacts of various places successively, and not at once; because an angel cannot be in several places at one time, as was said above (Q, A). Nor is it necessary for these contacts to be continuous. Nevertheless a certain kind of continuity can be found in such contacts. Because, as was said above (Q, A), there is nothing to hinder us from assigning a divisible place to an angel according to virtual contact; just as a divisible place is assigned to a body by contact of magnitude. Hence as a body successively, and not all at once, quits the place in which it was before, and thence arises continuity in its local movement; so likewise an angel can successively quit the divisible place in which he was before, and so his movement will be continuous. And he can all at once quit the whole place, and in the same instant apply himself to the whole of another place, and thus his movement will not be continuous.
Reply to Objection 1: This argument fails of its purpose for a twofold reason. First of all, because Aristotle's demonstration deals with what is indivisible according to quantity, to which responds a place necessarily indivisible. And this cannot be said of an angel.
Secondly, because Aristotle's demonstration deals with movement which is continuous. For if the movement were not continuous, it might be said that a thing is moved where it is in the term "wherefrom," and while it is in the term "whereto": because the very succession of "wheres," regarding the same thing, would be called movement: hence, in whichever of those "wheres" the thing might be, it could be said to be moved. But the continuity of movement prevents this; because nothing which is continuous is in its term, as is clear, because the line is not in the point. Therefore it is necessary for the thing moved to be not totally in either of the terms while it is being moved; but partly in the one, and partly in the other. Therefore, according as the angel's movement is not continuous, Aristotle's demonstration does not hold good. But according as the angel's movement is held to be continuous, it can be so granted, that, while an angel is in movement, he is partly in the term "wherefrom," and partly in the term "whereto" (yet so that such partiality be not referred to the angel's substance, but to the place); because at the outset of his continuous movement the angel is in the whole divisible place from which he begins to be moved; but while he is actually in movement, he is in part of the first place which he quits, and in part of the second place which he occupies. This very fact that he can occupy the parts of two places appertains to the angel from this, that he can occupy a divisible place by applying his power; as a body does by application of magnitude. Hence it follows regarding a body which is movable according to place, that it is divisible according to magnitude; but regarding an angel, that his power can be applied to something which is divisible.
Reply to Objection 2: The movement of that which is in potentiality is the act of an imperfect agent. But the movement which is by application of energy is the act of one in act: because energy implies actuality.
Reply to Objection 3: The movement of that which is in potentiality is the act of an imperfect but the movement of what is in act is not for any need of its own, but for another's need. In this way, because of our need, the angel is moved locally, according to Heb. 1:14: "They are all [*Vulg.: 'Are they not all . . . ?'] ministering spirits, sent to minister for them who receive the inheritance of salvation."
Objection 1: It would seem that an angel does not pass through intermediate space. For everything that passes through a middle space first travels along a place of its own dimensions, before passing through a greater. But the place responding to an angel, who is indivisible, is confined to a point. Therefore if the angel passes through middle space, he must reckon infinite points in his movement: which is not possible.
Objection 2: Further, an angel is of simpler substance than the soul. But our soul by taking thought can pass from one extreme to another without going through the middle: for I can think of France and afterwards of Syria, without ever thinking of Italy, which stands between them. Therefore much more can an angel pass from one extreme to another without going through the middle.
On the contrary, If the angel be moved from one place to another, then, when he is in the term "whither," he is no longer in motion, but is changed. But a process of changing precedes every actual change: consequently he was being moved while existing in some place. But he was not moved so long as he was in the term "whence." Therefore, he was moved while he was in mid-space: and so it was necessary for him to pass through intervening space.
I answer that, As was observed above in the preceding article, the local motion of an angel can be continuous, and non-continuous. If it be continuous, the angel cannot pass from one extreme to another without passing through the mid-space; because, as is said by the Philosopher (Phys. v, text 22; vi, text 77), "The middle is that into which a thing which is continually moved comes, before arriving at the last into which it is moved"; because the order of first and last in continuous movement, is according to the order of the first and last in magnitude, as he says (Phys. iv, text 99).
But if an angel's movement be not continuous, it is possible for him to pass from one extreme to another without going through the middle: which is evident thus. Between the two extreme limits there are infinite intermediate places; whether the places be taken as divisible or as indivisible. This is clearly evident with regard to places which are indivisible; because between every two points that are infinite intermediate points, since no two points follow one another without a middle, as is proved in Phys. vi, text. 1. And the same must of necessity be said of divisible places: and this is shown from the continuous movement of a body. For a body is not moved from place to place except in time. But in the whole time which measures the movement of a body, there are not two "nows" in which the body moved is not in one place and in another; for if it were in one and the same place in two "nows," it would follow that it would be at rest there; since to be at rest is nothing else than to be in the same place now and previously. Therefore since there are infinite "nows" between the first and the last "now" of the time which measures the movement, there must be infinite places between the first from which the movement begins, and the last where the movement ceases. This again is made evident from sensible experience. Let there be a body of a palm's length, and let there be a plane measuring two palms, along which it travels; it is evident that the first place from which the movement starts is that of the one palm; and the place wherein the movement ends is that of the other palm. Now it is clear that when it begins to move, it gradually quits the first palm and enters the second. According, then, as the magnitude of the palm is divided, even so are the intermediate places multiplied; because every distinct point in the magnitude of the first palm is the beginning of a place, and a distinct point in the magnitude of the other palm is the limit of the same. Accordingly, since magnitude is infinitely divisible and the points in every magnitude are likewise infinite in potentiality, it follows that between every two places there are infinite intermediate places.
Now a movable body only exhausts the infinity of the intermediate places by the continuity of its movement; because, as the intermediate places are infinite in potentiality, so likewise must there be reckoned some infinitudes in movement which is continuous. Consequently, if the movement be not continuous, then all the parts of the movement will be actually numbered. If, therefore, any movable body be moved, but not by continuous movement, it follows, either that it does not pass through all the intermediate places, or else that it actually numbers infinite places: which is not possible. Accordingly, then, as the angel's movement is not continuous, he does not pass through all intermediate places.
Now, the actual passing from one extreme to the other, without going through the mid-space, is quite in keeping with an angel's nature; but not with that of a body, because a body is measured by and contained under a place; hence it is bound to follow the laws of place in its movement. But an angel's substance is not subject to place as contained thereby, but is above it as containing it: hence it is under his control to apply himself to a place just as he wills, either through or without the intervening place.
Reply to Objection 1: The place of an angel is not taken as equal to him according to magnitude, but according to contact of power: and so the angel's place can be divisible, and is not always a mere point. Yet even the intermediate divisible places are infinite, as was said above: but they are consumed by the continuity of the movement, as is evident from the foregoing.
Reply to Objection 2: While an angel is moved locally, his essence is applied to various places: but the soul's essence is not applied to the things thought of, but rather the things thought of are in it. So there is no comparison.
Reply to Objection 3: In continuous movement the actual change is not a part of the movement, but its conclusion; hence movement must precede change. Accordingly such movement is through the mid-space. But in movement which is not continuous, the change is a part, as a unit is a part of number: hence the succession of the various places, even without the mid-space, constitutes such movement.
Objection 1: It would seem that an angel's movement is instantaneous. For the greater the power of the mover, and the less the moved resist the mover, the more rapid is the movement. But the power of an angel moving himself exceeds beyond all proportion the power which moves a body. Now the proportion of velocities is reckoned according to the lessening of the time. But between one length of time and any other length of time there is proportion. If therefore a body is moved in time, an angel is moved in an instant.
Objection 2: Further, the angel's movement is simpler than any bodily change. But some bodily change is effected in an instant, such as illumination; both because the subject is not illuminated successively, as it gets hot successively; and because a ray does not reach sooner what is near than what is remote. Much more therefore is the angel's movement instantaneous.
Objection 3: Further, if an angel be moved from place to place in time, it is manifest that in the last instant of such time he is in the term "whereto": but in the whole of the preceding time, he is either in the place immediately preceding, which is taken as the term "wherefrom"; or else he is partly in the one, and partly in the other, it follows that he is divisible; which is impossible. Therefore during the whole of the preceding time he is in the term "wherefrom." Therefore he rests there: since to be at rest is to be in the same place now and previously, as was said (A). Therefore it follows that he is not moved except in the last instant of time.
On the contrary, In every change there is a before and after. Now the before and after of movement is reckoned by time. Consequently every movement, even of an angel, is in time, since there is a before and after in it.
I answer that, Some have maintained that the local movement of an angel is instantaneous. They said that when an angel is moved from place to place, during the whole of the preceding time he is in the term "wherefrom"; but in the last instant of such time he is in the term "whereto." Nor is there any need for a medium between the terms, just as there is no medium between time and the limit of time. But there is a mid-time between two "nows" of time: hence they say that a last "now" cannot be assigned in which it was in the term "wherefrom," just as in illumination, and in the substantial generation of fire, there is no last instant to be assigned in which the air was dark, or in which the matter was under the privation of the form of fire: but a last time can be assigned, so that in the last instant of such time there is light in the air, or the form of fire in the matter. And so illumination and substantial generation are called instantaneous movements.
But this does not hold good in the present case; and it is shown thus. It is of the nature of rest that the subject in repose be not otherwise disposed now than it was before: and therefore in every "now" of time which measures rest, the subject reposing is in the same "where" in the first, in the middle, and in the last "now." On the other hand, it is of the very nature of movement for the subject moved to be otherwise now than it was before: and therefore in every "now" of time which measures movement, the movable subject is in various dispositions; hence in the last "now" it must have a different form from what it had before. So it is evident that to rest during the whole time in some (disposition), for instance, in whiteness, is to be in it in every instant of such time. Hence it is not possible for anything to rest in one term during the whole of the preceding time, and afterwards in the last instant of that time to be in the other term. But this is possible in movement: because to be moved in any whole time, is not to be in the same disposition in every instant of that time. Therefore all instantaneous changes of the kind are terms of a continuous movement: just as generation is the term of the alteration of matter, and illumination is the term of the local movement of the illuminating body. Now the local movement of an angel is not the term of any other continuous movement, but is of itself, depending upon no other movement. Consequently it is impossible to say that he is in any place during the whole time, and that in the last "now" he is in another place: but some "now" must be assigned in which he was last in the preceding place. But where there are many "nows" succeeding one another, there is necessarily time; since time is nothing else than the reckoning of before and after in movement. It remains, then, that the movement of an angel is in time. It is in continuous time if his movement be continuous, and in non-continuous time if his movement is non-continuous for, as was said (A), his movement can be of either kind, since the continuity of time comes of the continuity of movement, as the Philosopher says (Phys. iv, text 99).
But that time, whether it be continuous or not, is not the same as the time which measures the movement of the heavens, and whereby all corporeal things are measured, which have their changeableness from the movement of the heavens; because the angel's movement does not depend upon the movement of the heavens.
Reply to Objection 1: If the time of the angel's movement be not continuous, but a kind of succession of 'nows,' it will have no proportion to the time which measures the movement of corporeal things, which is continuous; since it is not of the same nature. If, however, it be continuous, it is indeed proportionable, not, indeed, because of the proportion of the mover and the movable, but on account of the proportion of the magnitudes in which the movement exists. Besides, the swiftness of the angel's movement is not measured by the quantity of his power, but according to the determination of his will.
Reply to Objection 2: Illumination is the term of a movement; and is an alteration, not a local movement, as though the light were understood to be moved to what is near, before being moved to what is remote. But the angel's movement is local, and, besides, it is not the term of movement; hence there is no comparison.
Reply to Objection 3: This objection is based on continuous time. But the same time of an angel's movement can be non-continuous. So an angel can be in one place in one instant, and in another place in the next instant, without any time intervening. If the time of the angel's movement be continuous, he is changed through infinite places throughout the whole time which precedes the last 'now'; as was already shown (A). Nevertheless he is partly in one of the continuous places, and partly in another, not because his substance is susceptible of parts, but because his power is applied to a part of the first place and to a part of the second, as was said above (A).