Summa contra Gentiles3.106 Chapter CVI. That the intellectual substance which gives efficacy to the practices of magic is not good according to virtue

We must furthermore inquire what is this intellectual nature by whose power these works are done.

And in the first place it is plain that it is not good and praiseworthy: for it is the mark of an ill-disposed mind to countenance things contrary to virtue. Now this is done in these arts: for they are often employed in order to further adultery, theft, murder and like malefices, wherefore those who practise these arts are called malejics. Therefore the intellectual nature on whose assistance these arts depend is not well disposed according to virtue.

Again. It is not the mark of a mind well disposed according to virtue, to befriend and assist men of evil life, rather than every upright man. Now those who practise these arts are often men of evil life. Therefore the intellectual nature from whose assistance these arts derive their efficacy is not well disposed according to virtue.

Further. It is the mark of a well disposed mind to guide men towards those goods that are proper to man, namely the goods of reason. Consequently to lead men away from these, and to draw men to goods of the least worth, shows a mind of evil disposition. Now by these arts men progress, not in the goods of reason, which are science and virtue, but in goods of least account, such as the discovery of stolen goods, the capture of thieves, and so forth. Therefore the intellectual substances whose assistance these arts employ, are not well disposed according to virtue.

Moreover. There is a certain deception and unreasonableness in the works of these arts: for they require a man indifferent to lustful pleasure, whereas they are frequently employed to further lustful intercourse. But there is nothing unreasonable or contradictory in the work of a well-disposed mind. Therefore these arts do not employ the assistance of an intellect that is well disposed as to virtue.

Besides. It is an ill-disposed mind that is incited by the commission of crime to lend his assistance to another. But this is done in these arts: for we read of innocent children being slain by those who practise them. Therefore the persons by whose assistance such things are done have an evil mind.

Again. The proper good of the intellect is truth. Since therefore it belongs to good to lead others to good, it belongs to any well-disposed intellect to lead others to truth. In the works of the magicians, however, many things are done by which men are mocked and deceived. The intellect whose help they use, therefore, is not morally well disposed.

Further. A well-disposed intellect is allured by truth in which it takes delight, but not by lies. The magicians, however, in their invocations make use of various lies, whereby they allure those whose help they employ; for they threaten certain impossible things, as for instance that, unless the one who is called upon gives help, he who invokes him will shatter the heavens or displace the stars, as Porphyry narrates in his Letter to Anebontes. Those intellectual substances, therefore, with whose help the works of the magicians are performed do not seem to be intellectually well disposed.

Moreover. That a superior should be subject as an inferior to one that commands him; or that an inferior should allow himself to be invoked as a superior, would seem to indicate a person of an ill-disposed mind. Now, magicians call upon those whose assistance they employ, as though these were their superiors: and as soon as they appear they command them as inferiors. In no way therefore are they seemingly of a well-disposed mind.

Hereby we refute the error of pagans who ascribed these works to the gods.