Summa Th. I EN Qu.68 a.4


We next consider the work of the third day. Under this head there are two points of inquiry:

(1) About the gathering together of the waters;

(2) About the production of plants.

Article: 1 Whether it was fitting that the gathering together of the waters should take place, as recorded, on the third day?

Objection: 1. It would seem that it was not fitting that the gathering together of the waters should take place on the third day. For what was made on the first and second days is expressly said to have been "made" in the words, "God said: Be light made," and "Let there be a firmament made."But the third day is contradistinguished from the first and the second days. Therefore the work of the third day should have been described as a making not as a gathering together.

2. Further, the earth hitherto had been completely covered by the waters, wherefore it was described as "invisible" [*Question [66], Article [1], Objection [1]]. There was then no place on the earth to which the waters could be gathered together.

3. Further, things which are not in continuous contact cannot occupy one place. But not all the waters are in continuous contact, and therefore all were not gathered together into one place.

4. Further, a gathering together is a mode of local movement. But the waters flow naturally, and take their course towards the sea. In their case, therefore, a Divine precept of this kind was unnecessary.

5. Further, the earth is given its name at its first creation by the words, "In the beginning God created heaven and earth." Therefore the imposition of its name on the third day seems to be recorded without necessity.

On the contrary The authority of Scripture suffices.

I answer that It is necessary to reply differently to this question according to the different interpretations given by Augustine and other holy writers. In all these works, according to Augustine (Gn ad lit. i, 15; iv, 22,34; De Gen. Contr. Manich. i, 5, 7), there is no order of duration, but only of origin and nature. He says that the formless spiritual and formless corporeal natures were created first of all, and that the latter are at first indicated by the words "earth" and "water." Not that this formlessness preceded formation, in time, but only in origin; nor yet that one formation preceded another in duration, but merely in the order of nature. Agreeably, then, to this order, the formation of the highest or spiritual nature is recorded in the first place, where it is said that light was made on the first day. For as the spiritual nature is higher than the corporeal, so the higher bodies are nobler than the lower. Hence the formation of the higher bodies is indicated in the second place, by the words, "Let there be made a firmament," by which is to be understood the impression of celestial forms on formless matter, that preceded with priority not of time, but of origin only. But in the third place the impression of elemental forms on formless matter is recorded, also with a priority of origin only. Therefore the words, "Let the waters be gathered together, and the dry land appear," mean that corporeal matter was impressed with the substantial form of water, so as to have such movement, and with the substantial form of earth, so as to have such an appearance.

According, however, to other holy writers [*Question [66], Article [1]] an order of duration in the works is to be understood, by which is meant that the formlessness of matter precedes its formation, and one form another, in order of time. Nevertheless, they do not hold that the formlessness of matter implies the total absence of form, since heaven, earth, and water already existed, since these three are named as already clearly perceptible to the senses; rather they understand by formlessness the want of due distinction and of perfect beauty, and in respect of these three Scripture mentions three kinds of formlessness. Heaven, the highest of them, was without form so long as "darkness" filled it, because it was the source of light. The formlessness of water, which holds the middle place, is called the "deep," because, as Augustine says (Contr. Faust. xxii, 11), this word signifies the mass of waters without order. Thirdly, the formless state of the earth is touched upon when the earth is said to be "void" or "invisible," because it was covered by the waters. Thus, then, the formation of the highest body took place on the first day. And since time results from the movement of the heaven, and is the numerical measure of the movement of the highest body, from this formation, resulted the distinction of time, namely, that of night and day. On the second day the intermediate body, water, was formed, receiving from the firmament a sort of distinction and order (so that water be understood as including certain other things, as explained above (Question [68], Article [3])). On the third day the earth, the lowest body, received its form by the withdrawal of the waters, and there resulted the distinction in the lowest body, namely, of land and sea. Hence Scripture, having clearly expresses the manner in which it received its form by the equally suitable words, "Let the dry land appear."

Reply to Objection: 1. According to Augustine [*Gen. ad lit. ii, 7,8; iii, 20], Scripture does not say of the work of the third day, that it was made, as it says of those that precede, in order to show that higher and spiritual forms, such as the angels and the heavenly bodies, are perfect and stable in being, whereas inferior forms are imperfect and mutable. Hence the impression of such forms is signified by the gathering of the waters, and the appearing of the land. For "water," to use Augustine's words, "glides and flows away, the earth abides" (Gn ad lit. ii, 11). Others, again, hold that the work of the third day was perfected on that day only as regards movement from place to place, and that for this reason Scripture had no reason to speak of it as made.

2. This argument is easily solved, according to Augustine's opinion (De Gen. Contr. Manich. i), because we need not suppose that the earth was first covered by the waters, and that these were afterwards gathered together, but that they were produced in this very gathering together. But according to the other writers there are three solutions, which Augustine gives (Gn ad lit. i, 12). The first supposes that the waters are heaped up to a greater height at the place where they were gathered together, for it has been proved in regard to the Red Sea, that the sea is higher than the land, as Basil remarks (Hom. iv in Hexaem.). The second explains the water that covered the earth as being rarefied or nebulous, which was afterwards condensed when the waters were gathered together. The third suggests the existence of hollows in the earth, to receive the confluence of waters. Of the above the first seems the most probable.

3. All the waters have the sea as their goal, into which they flow by channels hidden or apparent, and this may be the reason why they are said to be gathered together into one place. Or, "one place" is to be understood not simply, but as contrasted with the place of the dry land, so that the sense would be, "Let the waters be gathered together in one place," that is, apart from the dry land. That the waters occupied more places than one seems to be implied by the words that follow, "The gathering together of the waters He called Seas."

4. The Divine command gives bodies their natural movement and by these natural movements they are said to "fulfill His word." Or we may say that it was according to the nature of water completely to cover the earth, just as the air completely surrounds both water and earth; but as a necessary means towards an end, namely, that plants and animals might be on the earth, it was necessary for the waters to be withdrawn from a portion of the earth. Some philosophers attribute this uncovering of the earth's surface to the action of the sun lifting up the vapors and thus drying the land. Scripture, however, attributes it to the Divine power, not only in the Book of Genesis, but also Jb 38,10 where in the person of the Lord it is said, "I set My bounds around the sea," and Jr 5,22, where it is written: "Will you not then fear Me, saith the Lord, who have set the sand a bound for the sea?"

5. According to Augustine (De Gen. Contr. Manich. i), primary matter is meant by the word earth, where first mentioned, but in the present passage it is to be taken for the element itself. Again it may be said with Basil (Hom. iv in Hexaem.), that the earth is mentioned in the first passage in respect of its nature, but here in respect of its principal property, namely, dryness. Wherefore it is written: "He called the dry land, Earth." It may also be said with Rabbi Moses, that the expression, "He called," denotes throughout an equivocal use of the name imposed. Thus we find it said at first that "He called the light Day": for the reason that later on a period of twenty-four hours is also called day, where it is said that "there was evening and morning, one day." In like manner it is said that "the firmament," that is, the air, "He called heaven": for that which was first created was also called "heaven." And here, again, it is said that "the dry land," that is, the part from which the waters had withdrawn, "He called, Earth," as distinct from the sea; although the name earth is equally applied to that which is covered with waters or not. So by the expression "He called" we are to understand throughout that the nature or property He bestowed corresponded to the name He gave.

Article: 2 Whether it was fitting that the production of plants should take place on the third day?

Objection: 1. It would seem that it was not fitting that the production of plants should take place on the third day. For plants have life, as animals have. But the production of animals belongs to the work, not of distinction, but of adornment. Therefore the production of plants, as also belonging to the work of adornment, ought not to be recorded as taking place on the third day, which is devoted to the work of distinction.

2. Further, a work by which the earth is accursed should have been recorded apart from the work by which it receives its form. But the words of Gn 3,17, "Cursed is the earth in thy work, thorns and thistles shall it bring forth to thee," show that by the production of certain plants the earth was accursed. Therefore the production of plants in general should not have been recorded on the third day, which is concerned with the work of formation.

3. Further, as plants are firmly fixed to the earth, so are stones and metals, which are, nevertheless, not mentioned in the work of formation. Plants, therefore, ought not to have been made on the third day.

On the contrary It is said (Gn 1,12): "The earth brought forth the green herb," after which there follows, "The evening and the morning were the third day."

I answer that On the third day, as said (Article [1]), the formless state of the earth comes to an end. But this state is described as twofold. On the one hand, the earth was "invisible" or "void," being covered by the waters; on the other hand, it was "shapeless" or "empty," that is, without that comeliness which it owes to the plants that clothe it, as it were, with a garment. Thus, therefore, in either respect this formless state ends on the third day: first, when "the waters were gathered together into one place and the dry land appeared"; secondly, when "the earth brought forth the green herb." But concerning the production of plants, Augustine's opinion differs from that of others. For other commentators, in accordance with the surface meaning of the text, consider that the plants were produced in act in their various species on this third day; whereas Augustine (Gn ad lit. v, 5; viii, 3) says that the earth is said to have then produced plants and trees in their causes, that is, it received then the power to produce them. He supports this view by the authority of Scripture, for it is said (Gn 2,4-5): "These are the generations of the heaven and the earth, when they were created, in the day that . . . God made the heaven and the earth, and every plant of the field before it sprung up in the earth, and every herb of the ground before it grew." Therefore, the production of plants in their causes, within the earth, took place before they sprang up from the earth's surface. And this is confirmed by reason, as follows. In these first days God created all things in their origin or causes, and from this work He subsequently rested. Yet afterwards, by governing His creatures, in the work of propagation, "He worketh until now."Now the production of plants from out the earth is a work of propagation, and therefore they were not produced in act on the third day, but in their causes only. However, in accordance with other writers, it may be said that the first constitution of species belongs to the work of the six days, but the reproduction among them of like from like, to the government of the universe. And Scripture indicates this in the words, "before it sprung up in the earth," and "before it grew," that is, before like was produced from like; just as now happens in the natural course by the production of seed. Wherefore Scripture says pointedly (Gn 1,11): "Let the earth bring forth the green herb, and such as may seed," as indicating the production of perfection of perfect species, from which the seed of others should arise. Nor does the question where the seminal power may reside, whether in root, stem, or fruit, affect the argument.

Reply to Objection: 1. Life in plants is hidden, since they lack sense and local movement, by which the animate and the inanimate are chiefly discernible. And therefore, since they are firmly fixed in the earth, their production is treated as a part of the earth's formation.

2. Even before the earth was accursed, thorns and thistles had been produced, either virtually or actually. But they were not produced in punishment of man; as though the earth, which he tilled to gain his food, produced unfruitful and noxious plants. Hence it is said: "Shall it bring forth TO THEE."

3. Moses put before the people such things only as were manifest to their senses, as we have said (Question [67], Article [4]; Question [68], Article [3]). But minerals are generated in hidden ways within the bowels of the earth. Moreover they seem hardly specifically distinct from earth, and would seem to be species thereof. For this reason, therefore, he makes no mention of them.


We must next consider the work of adornment, first as to each day by itself, secondly as to all seven days in general.

In the first place, then, we consider the work of the fourth day, secondly, that of the fifth day, thirdly, that of the sixth day, and fourthly, such matters as belong to the seventh day.

Under the first head there are three points of inquiry:

(1) As to the production of the lights;

(2) As to the end of their production;

(3) Whether they are living beings?

Article: 1 Whether the lights ought to have been produced on the fourth day?

Objection: 1. It would seem that the lights ought not to have been produced on the fourth day. For the heavenly luminaries are by nature incorruptible bodies: wherefore their matter cannot exist without their form. But as their matter was produced in the work of creation, before there was any day, so therefore were their forms. It follows, then, that the lights were not produced on the fourth day.

2. Further, the luminaries are, as it were, vessels of light. But light was made on the first day. The luminaries, therefore, should have been made on the first day, not on the fourth.

3. Further, the lights are fixed in the firmament, as plants are fixed in the earth. For, the Scripture says: "He set them in the firmament." But plants are described as produced when the earth, to which they are attached, received its form. The lights, therefore, should have been produced at the same time as the firmament, that is to say, on the second day.

4. Further, plants are an effect of the sun, moon, and other heavenly bodies. Now, cause precedes effect in the order of nature. The lights, therefore, ought not to have been produced on the fourth day, but on the third day.

5. Further, as astronomers say, there are many stars larger than the moon. Therefore the sun and the moon alone are not correctly described as the "two great lights."

On the contrary Suffices the authority of Scripture.

I answer that In recapitulating the Divine works, Scripture says (Gn 2,1): "So the heavens and the earth were finished and all the furniture of them," thereby indicating that the work was threefold. In the first work, that of "creation," the heaven and the earth were produced, but as yet without form. In the second, or work of "distinction," the heaven and the earth were perfected, either by adding substantial form to formless matter, as Augustine holds (Gn ad lit. ii, 11), or by giving them the order and beauty due to them, as other holy writers suppose. To these two works is added the work of adornment, which is distinct from perfect. For the perfection of the heaven and the earth regards, seemingly, those things that belong to them intrinsically, but the adornment, those that are extrinsic, just as the perfection of a man lies in his proper parts and forms, and his adornment, in clothing or such like. Now just as distinction of certain things is made most evident by their local movement, as separating one from another; so the work of adornment is set forth by the production of things having movement in the heavens, and upon the earth. But it has been stated above (Question [69], Article [1]), that three things are recorded as created, namely, the heaven, the water, and the earth; and these three received their form from the three days' work of distinction, so that heaven was formed on the first day; on the second day the waters were separated; and on the third day, the earth was divided into sea and dry land. So also is it in the work of adornment; on the first day of this work, which is the fourth of creation, are produced the lights, to adorn the heaven by their movements; on the second day, which is the fifth, birds and fishes are called into being, to make beautiful the intermediate element, for they move in air and water, which are here taken as one; while on the third day, which is the sixth, animals are brought forth, to move upon the earth and adorn it. It must also here be noted that Augustine's opinion (Gn ad lit. v, 5) on the production of lights is not at variance with that of other holy writers, since he says that they were made actually, and not merely virtually, for the firmament has not the power of producing lights, as the earth has of producing plants. Wherefore Scripture does not say: "Let the firmament produce lights," though it says: "Let the earth bring forth the green herb."

Reply to Objection: 1. In Augustine's opinion there is no difficulty here; for he does not hold a succession of time in these works, and so there was no need for the matter of the lights to exist under another form. Nor is there any difficulty in the opinion of those who hold the heavenly bodies to be of the nature of the four elements, for it may be said that they were formed out of matter already existing, as animals and plants were formed. For those, however, who hold the heavenly bodies to be of another nature from the elements, and naturally incorruptible, the answer must be that the lights were substantially created at the beginning, but that their substance, at first formless, is formed on this day, by receiving not its substantial form, but a determination of power. As to the fact that the lights are not mentioned as existing from the beginning, but only as made on the fourth day, Chrysostom (Hom. vi in Gn) explains this by the need of guarding the people from the danger of idolatry: since the lights are proved not to be gods, by the fact that they were not from the beginning.

2. No difficulty exists if we follow Augustine in holding the light made on the first day to be spiritual, and that made on this day to be corporeal. If, however, the light made on the first day is understood to be itself corporeal, then it must be held to have been produced on that day merely as light in general; and that on the fourth day the lights received a definite power to produce determinate effects. Thus we observe that the rays of the sun have one effect, those of the moon another, and so forth. Hence, speaking of such a determination of power, Dionysius (Div. Nom. iv) says that the sun's light which previously was without form, was formed on the fourth day.

3. According to Ptolemy the heavenly luminaries are not fixed in the spheres, but have their own movement distinct from the movement of the spheres. Wherefore Chrysostom says (Hom. vi in Gn) that He is said to have set them in the firmament, not because He fixed them there immovably, but because He bade them to be there, even as He placed man in Paradise, to be there. In the opinion of Aristotle, however, the stars are fixed in their orbits, and in reality have no other movement but that of the spheres; and yet our senses perceive the movement of the luminaries and not that of the spheres (De Coel. ii, text. 43). But Moses describes what is obvious to sense, out of condescension to popular ignorance, as we have already said (Question [67], Article [4]; Question [68], Article [3]). The objection, however, falls to the ground if we regard the firmament made on the second day as having a natural distinction from that in which the stars are placed, even though the distinction is not apparent to the senses, the testimony of which Moses follows, as stated above (De Coel. ii, text. 43). For although to the senses there appears but one firmament; if we admit a higher and a lower firmament, the lower will be that which was made on the second day, and on the fourth the stars were fixed in the higher firmament.

4. In the words of Basil (Hom. v in Hexaem.), plants were recorded as produced before the sun and moon, to prevent idolatry, since those who believe the heavenly bodies to be gods, hold that plants originate primarily from these bodies. Although as Chrysostom remarks (Hom. vi in Gn), the sun, moon, and stars cooperate in the work of production by their movements, as the husbandman cooperates by his labor.

5. As Chrysostom says, the two lights are called great, not so much with regard to their dimensions as to their influence and power. For though the stars be of greater bulk than the moon, yet the influence of the moon is more perceptible to the senses in this lower world. Moreover, as far as the senses are concerned, its apparent size is greater.

Article: 2 Whether the cause assigned for the production of the lights is reasonable?

Objection: 1. It would seem that the cause assigned for the production of the lights is not reasonable. For it is said (Jr 10,2): "Be not afraid of the signs of heaven, which the heathens fear." Therefore the heavenly lights were not made to be signs.

2. Further, sign is contradistinguished from cause. But the lights are the cause of what takes place upon the earth. Therefore they are not signs.

3. Further, the distinction of seasons and days began from the first day. Therefore the lights were not made "for seasons, and days, and years," that is, in order to distinguish them.

4. Further, nothing is made for the sake of that which is inferior to itself, "since the end is better than the means" (Topic. iii). But the lights are nobler than the earth. Therefore they were not made "to enlighten it."

5. Further, the new moon cannot be said "to rule the night." But such it probably did when first made; for men begin to count from the new moon. The moon, therefore, was not made "to rule the night."

On the contrary Suffices the authority of Scripture.

I answer that As we have said above (Question [65], Article [2]), a corporeal creature can be considered as made either for the sake of its proper act, or for other creatures, or for the whole universe, or for the glory of God. Of these reasons only that which points out the usefulness of these things to man, is touched upon by Moses, in order to withdraw his people from idolatry. Hence it is written (Dt 4,19): "Lest perhaps lifting up thy eyes to heaven, thou see the sun and the moon and all the stars of heaven, and being deceived by error thou adore and serve them, which the Lord thy God created for the service of all nations." Now, he explains this service at the beginning of Genesis as threefold. First, the lights are of service to man, in regard to sight, which directs him in his works, and is most useful for perceiving objects. In reference to this he says: "Let them shine in the firmament and give life to the earth." Secondly, as regards the changes of the seasons, which prevent weariness, preserve health, and provide for the necessities of food; all of which things could not be secured if it were always summer or winter. In reference to this he says: "Let them be for seasons, and for days, and years." Thirdly, as regards the convenience of business and work, in so far as the lights are set in the heavens to indicate fair or foul weather, as favorable to various occupations. And in this respect he says: "Let them be for signs."

Reply to Objection: 1. The lights in the heaven are set for signs of changes effected in corporeal creatures, but not of those changes which depend upon the free-will.

2. We are sometimes brought to the knowledge of hidden effects through their sensible causes, and conversely. Hence nothing prevents a sensible cause from being a sign. But he says "signs," rather than "causes," to guard against idolatry.

3. The general division of time into day and night took place on the first day, as regards the diurnal movement, which is common to the whole heaven and may be understood to have begun on that first day. But the particular distinctions of days and seasons and years, according as one day is hotter than another, one season than another, and one year than another, are due to certain particular movements of the stars: which movements may have had their beginning on the fourth day.

4. Light was given to the earth for the service of man, who, by reason of his soul, is nobler than the heavenly bodies. Nor is it untrue to say that a higher creature may be made for the sake of a lower, considered not in itself, but as ordained to the good of the universe.

5. When the moon is at its perfection it rises in the evening and sets in the morning, and thus it rules the night, and it was probably made in its full perfection as were plants yielding seed, as also were animals and man himself. For although the perfect is developed from the imperfect by natural processes, yet the perfect must exist simply before the imperfect. Augustine, however (Gn ad lit. ii), does not say this, for he says that it is not unfitting that God made things imperfect, which He afterwards perfected.

Article: 3 Whether the lights of heaven are living beings?

Objection: 1. It would seem that the lights of heaven are living beings. For the nobler a body is, the more nobly it should be adorned. But a body less noble than the heaven, is adorned with living beings, with fish, birds, and the beasts of the field. Therefore the lights of heaven, as pertaining to its adornment, should be living beings also.

2. Further, the nobler a body is, the nobler must be its form. But the sun, moon, and stars are nobler bodies than plants or animals, and must therefore have nobler forms. Now the noblest of all forms is the soul, as being the first principle of life. Hence Augustine (De Vera Relig. xxix) says: "Every living substance stands higher in the order of nature than one that has not life." The lights of heaven, therefore, are living beings.

3. Further, a cause is nobler than its effect. But the sun, moon, and stars are a cause of life, as is especially evidenced in the case of animals generated from putrefaction, which receive life from the power of the sun and stars. Much more, therefore, have the heavenly bodies a living soul.

4. Further, the movement of the heaven and the heavenly bodies are natural (De Coel. i, text. 7,8): and natural movement is from an intrinsic principle. Now the principle of movement in the heavenly bodies is a substance capable of apprehension, and is moved as the desirer is moved by the object desired (Metaph. xii, text. 36). Therefore, seemingly, the apprehending principle is intrinsic to the heavenly bodies: and consequently they are living beings.

5. Further, the first of movables is the heaven. Now, of all things that are endowed with movement the first moves itself, as is proved in Phys. viii, text. 34, because, what is such of itself precedes that which is by another. But only beings that are living move themselves, as is shown in the same book (text. 27). Therefore the heavenly bodies are living beings.

On the contrary Damascene says (De Fide Orth. ii), "Let no one esteem the heavens or the heavenly bodies to be living things, for they have neither life nor sense."

I answer that, Philosophers have differed on this question. Anaxagoras, for instance, as Augustine mentions (De Civ. Dei xviii, 41), "was condemned by the Athenians for teaching that the sun was a fiery mass of stone, and neither a god nor even a living being." On the other hand, the Platonists held that the heavenly bodies have life. Nor was there less diversity of opinion among the Doctors of the Church. It was the belief of Origen (Peri Archon i) and Jerome that these bodies were alive, and the latter seems to explain in that sense the words (Qo 1,6), "The spirit goeth forward, surveying all places round about." But Basil (Hom. iii, vi in Hexaem.) and Damascene (De Fide Orth. ii) maintain that the heavenly bodies are inanimate. Augustine leaves the matter in doubt, without committing himself to either theory, though he goes so far as to say that if the heavenly bodies are really living beings, their souls must be akin to the angelic nature (Gn ad lit. ii, 18; Enchiridion lviii).

In examining the truth of this question, where such diversity of opinion exists, we shall do well to bear in mind that the union of soul and body exists for the sake of the soul and not of the body; for the form does not exist for the matter, but the matter for the form. Now the nature and power of the soul are apprehended through its operation, which is to a certain extent its end. Yet for some of these operations, as sensation and nutrition, our body is a necessary instrument. Hence it is clear that the sensitive and nutritive souls must be united to a body in order to exercise their functions. There are, however, operations of the soul, which are not exercised through the medium of the body, though the body ministers, as it were, to their production. The intellect, for example, makes use of the phantasms derived from the bodily senses, and thus far is dependent on the body, although capable of existing apart from it. It is not, however, possible that the functions of nutrition, growth, and generation, through which the nutritive soul operates, can be exercised by the heavenly bodies, for such operations are incompatible with a body naturally incorruptible. Equally impossible is it that the functions of the sensitive soul can appertain to the heavenly body, since all the senses depend on the sense of touch, which perceives elemental qualities, and all the organs of the senses require a certain proportion in the admixture of elements, whereas the nature of the heavenly bodies is not elemental. It follows, then, that of the operations of the soul the only ones left to be attributed to the heavenly bodies are those of understanding and moving; for appetite follows both sensitive and intellectual perception, and is in proportion thereto. But the operations of the intellect, which does not act through the body, do not need a body as their instrument, except to supply phantasms through the senses. Moreover, the operations of the sensitive soul, as we have seen, cannot be attributed to the heavenly bodies. Accordingly, the union of a soul to a heavenly body cannot be for the purpose of the operations of the intellect. It remains, then, only to consider whether the movement of the heavenly bodies demands a soul as the motive power, not that the soul, in order to move the heavenly body, need be united to the latter as its form; but by contact of power, as a mover is united to that which he moves. Wherefore Aristotle (Phys. viii, text. 42,43), after showing that the first mover is made up of two parts, the moving and the moved, goes on to show the nature of the union between these two parts. This, he says, is effected by contact which is mutual if both are bodies; on the part of one only, if one is a body and the other not. The Platonists explain the union of soul and body in the same way, as a contact of a moving power with the object moved, and since Plato holds the heavenly bodies to be living beings, this means nothing else but that substances of spiritual nature are united to them, and act as their moving power. A proof that the heavenly bodies are moved by the direct influence and contact of some spiritual substance, and not, like bodies of specific gravity, by nature, lies in the fact that whereas nature moves to one fixed end which having attained, it rests; this does not appear in the movement of heavenly bodies. Hence it follows that they are moved by some intellectual substances. Augustine appears to be of the same opinion when he expresses his belief that all corporeal things are ruled by God through the spirit of life (De Trin. iii, 4).

From what has been said, then, it is clear that the heavenly bodies are not living beings in the same sense as plants and animals, and that if they are called so, it can only be equivocally. It will also be seen that the difference of opinion between those who affirm, and those who deny, that these bodies have life, is not a difference of things but of words.

Reply to Objection: 1. Certain things belong to the adornment of the universe by reason of their proper movement; and in this way the heavenly luminaries agree with others that conduce to that adornment, for they are moved by a living substance.

2. One being may be nobler than another absolutely, but not in a particular respect. While, then, it is not conceded that the souls of heavenly bodies are nobler than the souls of animals absolutely it must be conceded that they are superior to them with regard to their respective forms, since their form perfects their matter entirely, which is not in potentiality to other forms; whereas a soul does not do this. Also as regards movement the power that moves the heavenly bodies is of a nobler kind.

3. Since the heavenly body is a mover moved, it is of the nature of an instrument, which acts in virtue of the agent: and therefore since this agent is a living substance the heavenly body can impart life in virtue of that agent.

4. The movements of the heavenly bodies are natural, not on account of their active principle, but on account of their passive principle; that is to say, from a certain natural aptitude for being moved by an intelligent power.

5. The heaven is said to move itself in as far as it is compounded of mover and moved; not by the union of the mover, as the form, with the moved, as the matter, but by contact with the motive power, as we have said. So far, then, the principle that moves it may be called intrinsic, and consequently its movement natural with respect to that active principle; just as we say that voluntary movement is natural to the animal as animal (Phys. viii, text. 27).

Summa Th. I EN Qu.68 a.4