Commentaria in Summam contra Gentiles, Liber III

Since it has been shown that God alone can perform miracles, St. Thomas wishes to show that, although separate substances cannot produce anything that is truly a miracle, they can nevertheless produce some effects that are marvelous to us ¹.

Concerning this, moreover, he does two things: first, he shows what is proposed; second, he determines concerning the marvels that are performed through the magic art, in the following chapter.

Concerning the first, he does three things: first, he removes a certain opinion of Avicenna, through which an answer could be made to the last argument of the preceding chapter; second, he explains and confirms the argument set down above ²; third, he explains what is proposed ³.

I. As to the first, he says that Avicenna, positing that matter obeys separate substances much more than contrary agents in nature ⁴, posited that at their apprehension some effects in these lower things, either of rain or of healing, sometimes follow without any intermediate corporeal agent.

Moreover, he shows this from a sign in this way. At the apprehension of our soul, when it has become strong in its imagination, the body is transmuted either to local motion, namely by falling from a high beam; or to heat, as in those who lust or are angry; or to coldness, as in those who fear; or sometimes to fever or to leprosy. And not only does its own body obey the apprehension of our soul, but also, if the soul is pure, not subject to bodily passions, and strong in its apprehension, external bodies obey it, as is shown through bewitchment (fascinatio). Therefore, much more, at the apprehension of separate substances, which are souls or the movers of the spheres, do some effects follow in these lower things without the action of any corporeal agent.

Moreover, this position, says St. Thomas, is in harmony with other positions of Avicenna: namely with this, that all substantial forms flow into these lower things from a separate substance; and with this, that corporeal agents only dispose matter to receive the impression of a separate agent.

It should be noted, as St. Thomas shows in De Potentia, q. VI, a. 3, that this position of Avicenna—namely, that separate substances can sometimes impress forms without a corporeal agent—follows by this deduction from that position by which he holds that forms flow from a separate substance into matter, while corporeal agents only dispose matter: Matter obeys a separate substance for the reception of a substantial form. Therefore it will not be unfitting if it also obeys for receiving dispositions to the form, since this belongs to a lesser power. Therefore, outside the order of corporeal agents, it can impress some forms by command alone.

II. Against this opinion, however, St. Thomas argues, saying that that opinion from which this one originates is not true, according to the doctrine of Aristotle, who in VII Metaphysics proves that the forms which are in matter are not from separate forms, but from forms existing in matter; for in this way a likeness is found between the maker and what is made.

To the sign assumed from our soul, moreover, he says that it is false that any transmutation of the body takes place from the apprehension of the soul alone. Rather, this does not take place except by means of local motion, since a transmutation of the body does not follow from an apprehension unless some affection is joined to the apprehension; but affections and passions of this kind occur with some determinate motion of the heart, from which there follows further the transmutation of the whole body.

To that which he introduces concerning bewitchment, he answers that this is not because the apprehension of one person immediately transmutes the body of another, but because, by means of the motion of the heart, it transmutes the conjoined body, the transmutation of which reaches the eye, by which something extrinsic can be infected, especially if it is easily transmutable; just as the eye of a menstruating woman infects a mirror.

III. Concerning the refutation of Avicenna's opinion taken from Aristotle in VII and VIII Metaphysics ⁵, arguing against Plato's ideas, and briefly touched upon here by St. Thomas, it should be noted that Aristotle argues in the same place as follows. What is made is like the maker. But that which is properly made is not form or matter, but the composite. Therefore the agent that causes natural things to exist through generation is not a form separated from matter, but a composite of matter and form. The major premise is proved: because every agent acts in a manner like to itself. But the minor: because to be made belongs to that to which being belongs; but the composite is what properly is, while form is that by which something is.

In this argument, however, it must be noted first, concerning the major premise and its proof, that there is discussion there concerning the immediate maker reducing form from potency to act.

It must be noted secondly that that likeness between the maker and what is made (which is the composite) is understood in this sense, according to the doctrine of St. Thomas in the First Part, q. cx, a. 2, and q. cxvii, a. 3: that the agent itself either is a composite, like fire generating fire; or it contains the whole composite itself in its virtuality, as regards form and matter, which is proper to God. Hence what is said—that matter does not obey a separate substance for the reception of form so that it can immediately introduce form into matter—is understood, as is said in De Potentia, in the place previously cited, of a created separate substance, whose power and essence is limited to a determinate genus; not, however, of the uncreated substance, whose power is infinite.

2. Concerning what is said of bewitchment, it should be noted, from the doctrine of St. Thomas where cited above, q. cxvii ⁶, that from a vehement commotion of the soul toward malice, which takes place with some inordinate motion of the heart, as happens especially in old women, the vital spirits are transmuted, especially in the eyes, to which more subtle spirits reach. But the eyes, by the exhalation of such spirits, infect the continuous air up to a determinate distance. And thus through sight some body is infected, especially one that is tender and easily receptive of impression, such as is the body of a child. And in this way also mirrors, if they are new and clean, contract a certain impurity from the look of a woman suffering menstruation, as is said in the book De Somno et Vigilia ⁷.

IV. Secondly, he explains and confirms the aforesaid argument of the preceding chapter ⁸: saying that it is in the power of a spiritual substance that a body obey it with respect to local motion, through which it can apply some naturally active things to produce some effects, just as the blacksmith's art applies fire to the softening of iron:—supply: and in no other way can it transmute matter. But this is not properly miraculous. Therefore created spiritual substances cannot perform miracles by their own power; although they can do this as they act in the divine power; as is clear from Gregory, who posits that one order of angels is deputed to performing miracles; and that some saints perform miracles from power, not only from intercession.

2. For the evidence of this last statement, it must be considered that St. Thomas touches on two ways, according to the mind of Gregory in the second book of the Dialogues ⁹, by which the saints effect miracles. One is through intercession: namely while by their express prayer they obtain from God that miracles be performed. The other is through the power granted to them by God; just as the thongs by which the countryman was held bound were at once loosed at the sight of St. Benedict, as Blessed Gregory relates ¹⁰.

Moreover, St. Thomas explains in two ways that the saints perform miracles from power. For in De Potentia Dei ¹¹, he explains that this is through a certain power supernaturally infused into some saints, not which is in them by way of a habit or permanent form, because thus they would perform miracles whenever they wished; but which is by way of an intentional form, which does not remain except at the presence of the agent, like light in the air and motion in an instrument.

In the Secunda Secundae, however, q. clxxviii, a. 1, ad 1, he posits that this is inasmuch as, without preceding manifest prayer, God works miraculously at the beck of a man: just as when Peter, by rebuking them, delivered to death Ananias and Sapphira when they lied ¹². For according to this interpretation, it seems it must be said that the saints sometimes perform miracles from power: not properly indeed as if they had in themselves some power of performing miracles; but according to a likeness, inasmuch as at their beck God sometimes performs a miracle without a manifest prayer of theirs by which they ask for the miraculous work; just as at the beck of a king those things are done which he wills to be done, on account of the power existing in him.—Nevertheless, that second interpretation of St. Thomas can also be taken in the first sense: so that God may be said to work miraculously at the beck of some saint, inasmuch as, without his manifestly asking, God infuses into him the power of performing a miracle by way of an intentional form.

3. Why, moreover, it belongs to separate substances to be able to move bodies locally, although they cannot transmute them to form, St. Thomas shows in the First Part, q. cx, a. 3; and De Potentia Dei, where cited above ¹³; and De Malo, q. xvi, a. 10, by this argument: because local motion is the first of motions, and therefore it belongs to it that other motions should proceed from a spiritual substance by means of it.

V. Thirdly, he shows that some effects that are marvelous to us proceed from separate substances ¹⁴. Moreover, he shows this from two suppositions. The first is that, when angels or demons apply natural things to some determinate effects, they use them as certain instruments.—The second, which is deduced from this, is that it is fitting that some higher effects should proceed from natural things inasmuch as spiritual substances use them as instruments: because from an instrument there proceeds an effect not only corresponding to its own power, but also beyond its proper power, inasmuch as it acts in the power of the principal agent; as is clear in a saw, and in an axe, and in natural heat.

These things being posited, St. Thomas says that effects of this kind—which, I say, are produced by spiritual substances when natural causes are applied—are rendered marvelous to us in two ways. In one way, inasmuch as natural causes are applied by spiritual substances to their proper effects in a manner unaccustomed to us: in which manner we marvel at the works of ingenious artisans.—In another way, from the fact that natural causes, applied to produce some effects, acquire something of power from the fact that they are instruments of spiritual substances. And this approaches more to the notion of a miracle.

2. It should be noted that the first way in which spiritual substances work some effects that are marvelous to us is when they work effects of corporeal causes only. At which we marvel either because they apply their proper active powers in a manner hidden to us: as if we should see wood being cut and did not see the secretly applied saw, we would marvel. Or because they apply some causes whose power we do not know: as if, a magnet having been applied, we should marvel that iron was attracted, not knowing the power of the magnet. Or because they apply natural causes more quickly than we can apply them. Or because they apply them at those hours in which celestial power, which they know more surely than men, cooperates more toward the intended effects.

To the second way, however, belong effects that cannot be produced by corporeal power per se, but only as an incorporeal power uses it as an instrument. These, moreover, are said to approach more to the notion of a miracle, because such effects are more above the nature of the created power known to us, which is corporeal power.