Commentaria in Summam contra Gentiles, Liber III

I. Having seen that the works of magicians derive their efficacy from an intellectual substance, St. Thomas wishes consequently to show that such a substance is neither good nor praiseworthy¹.

Concerning this, moreover, he does two things. First, he shows that a substance of this kind is not good and praiseworthy; second, he inquires into its malice, in the following chapter.

As to the first, he argues first thus. From magical arts patronage is afforded to certain things that are contrary to virtue, namely thefts, adulteries, and malefices of this kind; hence also those who use these arts are called malefactors. Therefore the intellectual nature whose aid magical arts use is not well disposed according to virtue. — The consequence is proved. Because to afford patronage to things that are contrary to virtue does not belong to any well-disposed intellect.

II. Second. Wicked men for the most part use arts of this kind. Therefore etc. — The consequence is proved. Because it does not belong to an intellect well disposed according to virtue to be familiar with and exhibit patronage to wicked men, and not to all the best men.

If it were said, according to the mind of Theophrastus², in response to the aforesaid reasons, that the intellectual substance affording efficacy to magical works is not evil per se, but only per accidens, insofar as it is drawn by magicians to the use of evil things—just as also the power of some herb is good, yet it becomes evil to someone insofar as perverse physicians use them badly: — it is clear that this is nothing. Because an intellectual substance of this kind voluntarily concurs with the works of magicians, and is not drawn by them to an evil use, in the manner of inanimate things. And therefore, if it concurs with evil works, this is not except from its evil disposition.

III. Third. Through arts of this kind men do not attain any progress in the goods of reason, which are the sciences and virtues, but in certain minimal things, such as the finding of thefts, and the catching of robbers, and the like. Therefore etc. — The consequence is proved. Because, since it belongs to a well-disposed intellect to lead men back to the goods of reason, which are the proper goods of men, to draw them away from these, by drawing them along to certain minimal goods, belongs to an unsuitably disposed intellect.

It must be noted that, although through magical arts some teachings of the sciences are sometimes received, nevertheless for the greater part they are practiced for certain minimal things. Therefore, when St. Thomas says that through arts of this kind men do not attain progress in the goods of reason, it is understood for the greater part.

Or it is to be understood of progress in the goods of reason with respect to judgment about things to be done, and with respect to the operations of the virtues: but not with respect to speculative cognition alone. For we see that men who use arts of this kind do not through them progress in acts of the virtues, which are the goods of reason, but are rather drawn to vices, and shrink from the true judgment of reason.

IV. Fourth. In the operations of the aforesaid arts a certain illusion and irrationality is seen. For they require a man not touched by sexual matters: although they are nevertheless sometimes employed to bring about illicit intercourses. Therefore etc. — The consequence is proved. Because in the operation of a well-disposed intellect nothing irrational and contrary to itself appears.

Fifth. Some in the execution of these arts are read to have slain innocent boys. Therefore etc. — The consequence is proved. Because he is not well disposed according to intellect who by certain crimes committed is provoked to bring aid to someone.

It must be noted that by the name intellect in the premises St. Thomas does not take the intellective power precisely taken, but the intellectual nature. Which is said to be well disposed according to virtue and according to morals, when it is directed according to the rules of reason and intellect into its operations; but evilly, when it does not operate according to rules of this kind. Because therefore the true judgment of the intellect holds that aid is not to be brought to those who, to attain some advantage of their own, commit grave crimes; nay rather, that they are to be repelled and hindered: therefore that intellectual substance is not well disposed which affords aid to men of this kind.

V. Sixth. In the works of magicians certain things are done by which men are mocked and deceived. Therefore etc. — The consequence is proved. Because, since the proper good of the intellect is truth; and it belongs to the good to bring about good: it seems to belong to a well-disposed intellect to lead others to the truth.

Seventh. Magicians in their invocations use certain lies, by which they may entice those whose aid they use: such as that, unless the one invoked brings aid, the one invoking will shatter the heavens, or pull down the stars, as Porphyry, in his Letter to Anebo³, recounts. Therefore etc. — The consequence is proved. Because a well-disposed intellect is enticed by truth, in which it takes delight, but not by lies.

Eighth. Magicians invoke those substances suppliantly, as superiors; but when they have arrived, they command them as inferiors. Therefore etc. — The consequence is proved. Because it does not seem to belong to one having a well-disposed intellect that, if it is superior, it should be subjected to one commanding it like an inferior; or, if it is inferior, that it should allow itself to be supplicated by him as by a superior.

It must be noted that although, on Matt. 3, the Gloss⁴ posits one grade of humility, in which is all justice, namely to be subject to a lesser; it is not, however, a grade of humility to be subject to an inferior arrogating to himself command over a superior, and to obey him. Nay rather, it would be against reason; and against the order instituted by God, who governs inferior things through superior things⁵. Therefore it is well said here that it does not belong to a well-disposed intellect, if it is superior, that it should be subjected to one commanding it like an inferior.

Lastly St. Thomas says that through this the error of the Gentiles is excluded, who attribute operations of this kind to the gods.