Summa contra Gentiles3.102 Chapter CII. That God alone works miracles

From what has been said it can be shown that God alone can work miracles.

For whatever is entirely subject to an order cannot do anything above that order. Now, every creature is placed under the order established in things by God. Therefore no creature can do anything above that order: which is to work miracles.

Again. When a finite power produces its proper effect to which it is confined, it is not a miracle: although it may be wonderful to one who does not understand that power: thus to an ignorant person it is wonderful that the magnet attracts iron, or that a small fish should stop a ship. Now every creature’s power is limited to one definite effect, or to some. Therefore whatever is done by the power of any creature whatsoever, cannot be properly described as a miracle, although it may be wonderful to one who does not understand the power of the creature in question. But that which is done by the power of God, which, being infinite, is incomprehensible, is truly a miracle.

Moreover. Every creature requires in its action a subject on which to act: for it belongs to God alone to make something out of nothing, as we proved above. Now, that which requires a subject in its action, can do nothing but those things to which that subject is in potentiality: since the agent acts on the subject in order to bring it from potentiality to act. Therefore even as a creature cannot create, so neither can it do in a thing, save what is in the potentiality of that thing. But in many miracles wrought by God, something is done in a thing, that is not in that thing’s potentiality: for instance that the dead live again, that the sun recede, that two bodies occupy the same place. Wherefore such miracles cannot be wrought by any created power.

Further. The subject acted upon is ordered both to the agent that brings it from potentiality to act, and to the act to which it is brought. Accordingly just as any particular subject is in potentiality to a particular definite act, and not to any act, so it cannot be brought from potentiality to a definite act, except by some definite agent: for agents must needs differ according as they introduce different acts: thus, whereas air is potentially fire or water, one agent makes it to be actually fire, and another makes it to be actually water. Likewise it is clear that corporeal matter is not brought to a perfect actuality by the sole action of a universal power, and there must needs be some proper agent, whereby the action of the universal power is determined to a definite effect. Nevertheless corporeal matter can be brought to a less perfect actuality by the universal power alone, without a particular agent: thus perfect animals are not formed by the power of a heavenly body alone, but determinate seed is necessary; whereas the power of a heavenly body, without any seed, suffices for the generation of certain imperfect animals. Accordingly, effects produced among these lower things, if they be of a nature to be wrought by universal higher causes, without the action of particular inferior causes, can be produced in this way without any miracle: thus it is not a miracle that animals be formed from putrefaction without seed. But if they be not of a nature to be produced by superior causes alone, then particular inferior causes are required for their perfect formation. Now there is no miracle if an effect be produced by a higher cause, by means of its proper principles. Therefore it is altogether impossible for miracles to be wrought by the power of the higher creatures.

Moreover. Seemingly these amount to the same:—the production of a work out of a subject;—the production of that to which the subject is in potentiality;—and the orderly production of something through definite intermediary stages. Because a subject is not in proximate potentiality to the ultimate effect, until it has arrived at the middle stage: thus food is not in immediate potentiality flesh, but only when it is changed into blood. Now, every creature needs a subject in order to produce something: nor can it produce other than that to which the subject is in potentiality, as we have shown. Therefore it cannot produce anything without bringing the subject to actuality through definite intervening stages. Therefore miracles which consist in something being done without observing the order in which it is naturally feasible, cannot be worked by the power of a creature.

Also. There is a natural order to be observed in the various kinds of movement. The first is local movement; hence it is the cause of other movements, because in every genus that which is first is the cause of all that follows in that gemis. Now every effect that is produced in this lower world, must needs result from some generation or alteration: and consequently it must be caused through something that is moved locally, if it be the effect of an incorporeal agent which, properly speaking, is incapable of local movement. Moreover, no effect that is caused by incorporeal substances through corporeal instruments is a miracle; since bodies have no operation that is not natural. Therefore created incorporeal substances cannot work miracles by their own power: and much less corporeal substances whose every action is natural.

Therefore it belongs to God alone to work miracles. For He is above the order which contains all things, as one from whose providence the whole of this order is derived. Moreover His power, being absolutely infinite, is not confined to any special effect, nor to the producing of its effect in any particular way or order.

Wherefore it is said of God in the Psalm: Who alone doth great wonders.