CONTRA GENTILES - BOOK THREE: PROVIDENCE -Chapter 82 THAT LOWER BODIES ARE RULED BY GOD THROUGH CELESTIAL BODIES

[1] Now, just as there is a difference between higher and lower intellectual substances, so also is there such a difference between corporeal substances. But intellectual substances are ruled by the higher ones, since the disposition of divine providence descends proportionally to the lowest, as we have said already. Therefore, on a like basis, the lower bodies are ordered through the higher ones.

[2] Again, the higher a body is in place, the more formal is it found to be. And even the place of a lower body reasonably follows this rule, since it is the function of form to limit, just as it is of place. In fact, water is more formal than earth, air than water, fire than air. But the celestial bodies are superior in place to all bodies. So, they are more formal than all the others, and, therefore, more active. So, they act on the lower bodies; thus, the lower ones are disposed by them.

[3] Besides, that which is in its nature perfected without contrariety is more universal than that which is not perfected in its nature without contrariety. Indeed, contrariety arises from the various things that determine and contract a genus; hence, in the realm of understanding, because it is universal the species of contraries are not contraries, for they may co-exist. But celestial bodies are perfected without any contrariety in their natures, for they are neither light nor heavy, neither hot nor cold. However, lower bodies are not perfected in their natures without some contrariety. Their motions also demonstrate this, for there is nothing contrary to the circular motion of the celestial bodies, and, consequently, there can be no violence in regard to them; but there are contraries to the motion of lower bodies, namely, downward motion as opposed to upward motion. So, celestial bodies are possessed of more universal power than lower bodies. But universal powers move particular ones, as is evident from what we have said. Therefore, celestial bodies move and dispose lower bodies.

[4] Moreover, it was shown above that all things are ruled through intellectual substances. But celestial bodies are more like intellectual substances than are other bodies because the former are incorruptible. They are also nearer to them, inasmuch as they are moved immediately by them, as we showed above. Therefore, the lower bodies are ruled by them.

[5] Furthermore, the first source of motion must be something immutable. So, the things that are nearest to immutability should be movers of the rest. But celestial bodies approach more closely to the immutability of the first source than do lower bodies, for they are not moved except by one kind of motion, namely, local motion; while other bodies are moved by all the species of motion. Therefore, the celestial bodies move and govern the lower bodies.

[6] Again, the first in any genus is the cause of members which are posterior. Now, in regard to all other motions, the first is the motion of the heavens; first of all, of course, because local motion is first among all motions, This is so in regard to time, for it alone can be perpetual, as is proved in the Physics VIII [7: 260b 29]. It is also so in regard to nature, for without it there cannot be any other kind of motion, In fact, a thing is not increased unless there be a preceding alteration by which what was formerly unlike is changed and becomes like; nor can alteration be accomplished unless there be a preceding local change, since for alteration to be achieved the agent of alteration must now be brought closer to the thing altered than it was before. It is also prior in perfection, because local motion does not change the thing in regard to any inherent factor but only according to something extrinsic; for this reason it belongs to an already perfected thing.

Secondly, even among local motions the circular is prior. And again, in regard to time: because it alone can be perpetual, as is proved in the Physics [VIII, 8: 261b 27]. And in regard to nature: for it is more simple and unified, since it is not divided into beginning, middle, and end; rather, the whole motion is like a middle. And even in perfection: because it is brought back to its origin.

Thirdly, because only the motion of the heavens is found always to be regular and uniform, for in the case of the natural motions of heavy and light things there is an increase in velocity toward the end; in the case of violent motion, there is an increase in retardation. So, the motion of the heavens must be the cause of all other motions.

[7] Besides, as the absolutely immobile is to unqualified motion, so is the immobile, that is qualified by a given motion, related to that motion. Now, that which is absolutely immobile is the source of all motion, as we proved above. So, what is immobile in regard to alteration is the source of all alteration. Now, the celestial bodies, alone among bodily things, are inalterable; their condition shows this, for it is always the same. So, the celestial body is the cause of all alteration in things that are changed by alteration. Now, in these lower bodies alteration is the source of all motion, for through alteration a thing achieves increase and generation, whereas the agent of generation is a self-mover in the local motion of heavy and light things. Therefore, the heavens must be the cause of all motion in these lower bodies.

[8] Thus, it is evident that lower bodies are ruled by God through the celestial bodies.

Next - CONTRA GENTILES - BOOK THREE: PROVIDENCE -Chapter 83 EPILOGUE TO THE PRECEDING CHAPTERS