Saturday, 4 February 2012

Question 57 - The Angels' Knowledge of Material Things

Why this Question Matters.

Having discussed the angels’ knowledge of immaterial things in the previous question, it seems quite natural that he now asks about their knowledge of material things. The general answer to how angels know of material things is that God puts the knowledge there as part of their natures. Aquinas is not satisfied simply with such a deus ex machina answer and insists on spelling out how this knowledge comes to be in a number of particular cases that would at first seem to be awkward.

The Thread of the Argument

A1: The intellect of an angel is simple in the sense of not having all of the components that the intellect of a human being has. Angels do not know things through sense data nor do they have an imagination. How then can they know material things? The objections and the sed contra of this question hold in tension the ideas that “of course angels know about material things because they are higher beings than us” and “but they lack the means by which material things are understood”.

It is no surprise that the former observation wins out: the mistake in the latter position arises from thinking that angels must perceive material things in the same way that we do. Angels participate more perfectly in God’s goodness, as they are higher in the order of creation. This means that material things pre-exist in the intellects of angels (having been put there by God). As angels are purely intellectual beings and because the existence of a thing is in the mode of that in which it exists, this pre-existence of material objects in the angels must be an intellectual existence (an esse intentionale as we saw in Ia.q56.a2). Hence angels do know material things.

In the reply to the second objection, Aquinas reinforces the point that the intellect apprehends the essence of a thing, the what-it-is-ness of the object. In contrast, the senses apprehend the some of the exterior accidents of a thing (from which the active intellect derives the intelligible species, which in turn allows the intellect to infer the essence of the thing). Likewise the imagination apprehends likenesses of sensible things rather than the essence of the thing. Therefore it’s important to note that the angels’ knowledge of material things is a very direct knowledge of unmediated perception.

A2: Returning to a theme raised in Ia.q56.a1, there would seem to be a tension between the angels’ guardianship of singular individual human beings and the possibility that angels can actually have any knowledge of singulars. That the latter might be a problem, recall that Aristotle argues that intellectual knowledge is the knowledge of essences and thus of universals whereas sensation is the knowledge of singulars; as angels only have intellectual knowledge, they surely cannot have knowledge of individuals.

Aquinas gives a surprisingly long answer to this question, a fact that probably reflects the diversity of philosophical opinion at the time. He is, however, quite uncompromising; to deny completely the knowledge of singulars to the angels would be to deny the Catholic belief that angels minister to singulars lower in the hierarchy of creation. He also alludes to an intermediate position that the angels have knowledge of singulars but only through knowledge of the universal causes of these singulars. Aquinas discards this position as inadequate as it fails to do justice to what it means to have knowledge of singulars; predicting that an eclipse will happen by analysing the motion of the sun and moon is not the same as experiencing the eclipse as it happens here and now. Aquinas will return to the theme of knowledge through causes in the next article when he considers the angels’ knowledge of future things.

Aquinas observes that humans know things by a diversity of cognitive powers. For example, we know immaterial and universal things through the intellect; singular and corporeal things through senses. Angels, however, have a more unified and integrated intellective power. We can see something like this in the common sense of human beings; although we identify five different senses, we also recognize that these senses work together and are integrated to the extent that we can meaningfully differentiate between whiteness and sweetness.

Returning to the theme of Ia.q56.a2, Aquinas recalls that things flow forth from God in two modes: as existing in themselves but also as existing in angelic cognition. Just as God knows the things that He creates both in their universality and in their individuality, so also does he communicate this knowledge, universal and singular, to the angels.

A3: If angels are so smart what do they know of the future? Do they know future things to the extent that God knows future things? After all, God exists in eternity in which there is no notion of future and past; so, angels exist in aeviternity and similar considerations must apply.

Aquinas identifies that the knowledge of a future thing can be considered under two types: it can be considered as knowledge in its cause and as knowledge in itself. We know future things in their causes when we can predict what will happen based on what has happened; we see two cars skidding towards each other at high speed, we can predict that there will be a crash. Such knowledge is not infallible but probabilistic. We may simply not know of intervening causes that issue in a different outcome to that which we predict; at the last minute the driver of one of the cars may regain control and steer away from the other car. In contrast, we know things in themselves (to the extent to which we can know them) when we have cognition of them. So we do not have knowledge of future things in themselves but God does. In fact, only God has such knowledge of future things in themselves; the angels have a more perfect knowledge of future things in their causes that we do, but they do not have the knowledge of future things in themselves.

Angels may exist in aeviternity, but that does not mean that there is no change for them. There can be a succession of intelligible conceptions in the intellect of an angel as their intellect moves from potentiality to actuality.

A4: Aquinas attacks the question of whether angels can know the thoughts of our hearts in a manner that might seem dual to the approach that he took in the previous article about the angels’ knowledge of future things. There are two ways in which the thoughts of our hearts can be known by another. In the first instance they can be known by their effects: from the expression on someone’s face to their exterior acts, what lies behind may be inferred to a greater or lesser extent. This is the type of knowledge that the angels have of the thoughts of our hearts; but they are much better at it than we are! They have a much deeper insight into our hearts via externals that we can possibly hope for.

The second way that the thoughts of our hearts can be known by another is as they actually exist in our intellects (as far as thoughts are concerned) and in our wills (when it comes to affections). This type of “interior” knowledge is restricted to God.

A5: Finally in this question, Aquinas asks whether the angels know the “mysteries of grace” (or “all the mysteries of grace” if one reads the prologue to this question). By this he means those supernatural effects produced by God in creation; the effects in creation of the economic Trinity rather than things to do with the immanent Trinity.

To answer this question Aquinas distinguishes between the natural knowledge of the angels and their beatified knowledge. Natural knowledge is the knowledge that they have through their essence and the innate intelligible species implanted in them by God. On the other hand, their beatified knowledge is that which comes to them by their being raised to the supernatural (see Ia.q62 for more details of this). As so raised, they do not know all the mysteries of grace but only those revealed to them by God. Furthermore the higher the level of the angel, the more the angel knows of such mysteries.

Handy Concepts

  • Material things pre-exist in the intellects of angels as an intellectual knowledge.
  • The intellect (be it human or angelic) apprehends the essences of things.
  • God communicates the knowledge of things in their universality and their particularity to the angels.
  • God has created the angels as intellectual beings that know stuff as part of their being.
  • Angels know the future only insofar as they know the causes of things; they do have this knowledge to a degree of perfection much higher than ours.
  • Angels know the thoughts of our hearts only insofar as they know the effects of that flow from what is in our hearts; again, they know this much better than we do.
  • Angels know the mysteries of grace only insofar as they are raised to the supernatural level and only insofar as God reveals them.


  • It is curious that Aquinas does not raise Ephesians 3:10 in the discussion of the fifth article. The discussion that he gives in his commentary on the book of Ephesians expands on what he writes here.
  • One might identify synaesthesia as a failure of the common sense.


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