Since we cannot be present at the holy ceremonies in honor of the angels, we should not let this time of devotion go by fruitlessly; rather, such time as we do not spend in singing their praises, we should spend in writing about them. And because our aim is to present as best we can the excellence of the holy angels, we ought to begin with man’s earliest conjectures about the angels. In this way, we shall be in a position to accept whatever we find that agrees with faith, and refute whatever is opposed to Catholic teaching. ~ Thomas Aquinas, De Angelis

In The Multiple States of Being, Rene Guenon recommends Aquinas’ short theological treatise on the angels as an introduction to an understanding of angels as higher, supra-individual states of being. Aquinas himself looks back to the ancient Greeks to begin his study of angelic beings. After all, if angels, demons, and gods are real entities or states of being and not merely figments of the imagination or objects of belief, then they can be understood by any metaphysician. Aquinas explains:

Now it is clear that every intellectual substance receives the intellected form according to its totality, or otherwise it would not be able to know it in its totality. For it is thus that the intellect understands a thing insofar as the form of that thing exists in it.

Thus, a complete understanding of the angelic hierarchy is possible only for the intellect that contains the form, that is, the idea of the angel, that is, it participates in the higher form. This is the metaphysical principle, “to know is to be”.

Gods and the Celestial Hierarchy

Confusion results from terminology, since we tend to consider the “angels” as good and “demons” as bad. However, Aquinas clarifies this by pointing out that angels can be evil and that according to Plato, demons can be good or evil. Regarding Plato, Aquinas writes:

In this way, therefore, between us and the highest God, it is clear that they posited four orders, namely, that of the secondary gods, that of the separate intellects, that of the heavenly souls, and that of the good or wicked demons. If all these things were true, then all these intermediate orders would be called by us “angels”, for Sacred Scripture refers to the demons themselves as angels.

So, Aquinas accepted the gods as angels. He also considered that the planets were ensouled. Hence, he seems to be implying that the gods Mars, Venus, Jupiter, Saturn and so on were actually angels. This aligns him with the Hermetic Tradition. Valentin Tomberg, in Meditations on the Tarot, assigns the following correspondences:

Preternatural Phenomena

Aquinas recognizes certain preternatural phenomena and attributes them to the influence of higher intellectual substance. Keep in mind that in the following passage, the Platonic “demon” is the same as the Catholic “angel”, so no inference should be made that it necessarily implies an evil or satanic influence.

[Certain followers of Aristotle] say that it is through the influence of the stars that persons who are possessed sometimes foretell future events, for the realization of which there is a certain disposition in nature through the heavenly bodies. But in such cases, there are manifestly certain works which cannot in any way be reduced to a corporeal cause. For example, that people in a trance should speak in a cultivated way of sciences which they do not know, since they are unlettered folk; and that those who have scarcely left the village in which they were born, speak with fluency the vernacular of a foreign people. Likewise, in the works of magicians, certain images are said to be conjured up which answer questions and move about, all of which could not be accomplished by any corporeal cause. Therefore, as the Platonists see it, who could evidently assign a cause of these effects, except to say that these are brought about through demons.

On Infallibility

We see here that Aquinas asserts the traditional teaching that gnosis is infallible. Unfortunately, self-deception is not so easily overcome.

Accordingly, Augustine says in the Book of Eighty-Three Questions: “Everyone who is deceived, that, indeed, in which he is deceived, he does not understand.” And accordingly, concerning those things which we grasp properly by our intellect as well as concerning the first principles, no one can be deceived.