56
OF THE ANGEL'S KNOWLEDGE OF IMMATERIAL THINGS
We now inquire into the knowledge of the angels with regard to the objects known by
them. We shall treat of their knowledge, first, of immaterial things, secondly of things
material. Under the first heading there are three points of inquiry:
(1) Does an angel know himself?
(2) Does one angel know another?
(3) Does the angel know God by his own natural principles?

ARTICLE 1
Whether an angel knows himself?
Objection 1
It would seem that an angel does not know himself. For Dionysius says that
"the angels do not know their own powers" (Coel. Hier. vi). But, when the
substance is known, the power is known. Therefore an angel does not know his own essence.
Objection 2
Further, an angel is a single substance, otherwise he would not act, since acts
belong to single subsistences. But nothing single is intelligible. Therefore, since the
angel possesses only knowledge which is intellectual, no angel can know himself.
Objection 3
Further, the intellect is moved by the intelligible object: because, as stated
in De Anima iii, 4 understanding is a kind of passion. But nothing is moved by or is
passive to itself; as appears in corporeal things. Therefore the angel cannot understand
himself.
On the contrary
On the contrary, Augustine says (Gen. ad lit. ii) that "the angel knew himself
when he was established, that is, enlightened by truth."
Body
I answer that, As is evident from what has been previously said (Q14, ARTICLE 2; Q54,
ARTICLE 2), the object is on a different footing in an immanent, and in a transient,
action. In a transient action the object or matter into which the action passes is
something separate from the agent, as the thing heated is from what gave it heat, and the
building from the builder; whereas in an immanent action, for the action to proceed, the
object must be united with the agent; just as the sensible object must be in contact with
sense, in order that sense may actually perceive. And the object which is united to a
faculty bears the same relation to actions of this kind as does the form which is the
principle of action in other agents: for, as heat is the formal principle of heating in
the fire, so is the species of the thing seen the formal principle of sight to the eye.
It must, however, be borne in mind that this image of the object exists sometimes only
potentially in the knowing faculty; and then there is only knowledge in potentiality; and
in order that there may be actual knowledge, it is required that the faculty of knowledge
be actuated by the species. But if it always actually possesses the species, it can
thereby have actual knowledge without any preceding change or reception. From this it is
evident that it is not of the nature of knower, as knowing, to be moved by the object, but
as knowing in potentiality. Now, for the form to be the principle of the action, it makes
no difference whether it be inherent in something else, or self-subsisting; because heat
would give forth heat none the less if it were self-subsisting, than it does by inhering
in something else. So therefore, if in the order of intelligible beings there be any
subsisting intelligible form, it will understand itself. And since an angel is immaterial,
he is a subsisting form; and, consequently, he is actually intelligible. Hence it follows
that he understands himself by his form, which is his substance.
Reply to Objection 1
That is the text of the old translation, which is amended in the new one,
and runs thus: "furthermore they," that is to say the angels, "knew their
own powers": instead of which the old translation read---"and furthermore they
do not know their own powers." Although even the letter of the old translation might
be kept in this respect, that the angels do not know their own power perfectly; according
as it proceeds from the order of the Divine Wisdom, Which to the angels is
incomprehensible.
Reply to Objection 2
We have no knowledge of single corporeal things, not because of their
particularity, but on account of the matter, which is their principle of individuation.
Accordingly, if there be any single things subsisting without matter, as the angels are,
there is nothing to prevent them from being actually intelligible.
Reply to Objection 3
It belongs to the intellect, in so far as if is in potentiality, to be
moved and to be passive. Hence this does not happen in the angelic intellect, especially
as regards the fact that he understands himself. Besides the action of the intellect is
not of the same nature as the action found in corporeal things, which passes into some
other matter.

ARTICLE 2
Whether one angel knows another?
Objection 1
It would seem that one angel does not know another. For the Philosopher says (De
Anima iii, text. 4), that if the human intellect were to have in itself any one of the
sensible things, then such a nature existing within it would prevent it from apprehending
external things; as likewise, if the pupil of the eye were colored with some particular
color, it could not see every color. But as the human intellect is disposed for
understanding corporeal things, so is the angelic mind for understanding immaterial
things. Therefore, since the angelic intellect has within itself some one determinate
nature from the number of such natures, it would seem that it cannot understand other
natures.
Objection 2
Further, it is stated in De Causis that "every intelligence knows what is
above it, in so far as it is caused by it; and what is beneath it, in so far as it is its
cause." But one angel is not the cause of another. Therefore one angel does not know
another.
Objection 3
Further, one angel cannot be known to another angel by the essence of the one
knowing; because all knowledge is effected by way of a likeness. But the essence of the
angel knowing is not like the essence of the angel known, except generically; as is clear
from what has been said before (Q50, ARTICLE 4; Q55, ARTICLE 1, ad 3). Hence, it follows
that one angel would not have a particular knowledge of another, but only a general
knowledge. In like manner it cannot be said that one angel knows another by the essence of
the angel known; because that whereby the intellect understands is something within the
intellect; whereas the Trinity alone can penetrate the mind. Again, it cannot be said that
one angel knows the other by a species; because that species would not differ from the
angel understood, since each is immaterial. Therefore in no way does it appear that one
angel can understand another.
Objection 4
Further, if one angel did understand another, this would be either by an innate
species; and so it would follow that, if God were now to create another angel, such an
angel could not be known by the existing angels; or else he would have to be known by a
species drawn from things; and so it would follow that the higher angels could not know
the lower, from whom they receive nothing. Therefore in no way does it seem that one angel
knows another.
On the contrary
On the contrary, We read in De Causis that "every intelligence knows the things
which are not corrupted."
Body
I answer that, As Augustine says (Gen. ad lit. lit. ii), such things as pre-existed
from eternity in the Word of God, came forth from Him in two ways: first, into the angelic
mind; and secondly, so as to subsist in their own natures. They proceeded into the angelic
mind in such a way, that God impressed upon the angelic mind the images of the things
which He produced in their own natural being. Now in the Word of God from eternity there
existed not only the forms of corporeal things, but likewise the forms of all spiritual
creatures. So in every one of these spiritual creatures, the forms of all things, both
corporeal and spiritual, were impressed by the Word of God; yet so that in every angel
there was impressed the form of his own species according to both its natural and its
intelligible condition, so that he should subsist in the nature of his species, and
understand himself by it; while the forms of other spiritual and corporeal natures were
impressed in him only according to their intelligible natures, so that by such impressed
species he might know corporeal and spiritual creatures.
Reply to Objection 1
The spiritual natures of the angels are distinguished from one another in
a certain order, as was already observed (Q50, ARTICLE 4, ad 1,2). So the nature of an
angel does not hinder him from knowing the other angelic natures, since both the higher
and lower bear affinity to his nature, the only difference being according to their
various degrees of perfection.
Reply to Objection 2
The nature of cause and effect does not lead one angel to know another,
except on account of likeness, so far as cause and effect are alike. Therefore if likeness
without causality be admitted in the angels, this will suffice for one to know another.
Reply to Objection 3
One angel knows another by the species of such angel existing in his
intellect, which differs from the angel whose image it is, not according to material and
immaterial nature, but according to natural and intentional existence. The angel is
himself a subsisting form in his natural being; but his species in the intellect of
another angel is not so, for there it possesses only an intelligible existence. As the
form of color on the wall has a natural existence; but, in the deferent medium, it has
only intentional existence.
Reply to Objection 4
God made every creature proportionate to the universe which He determined
to make. Therefore had God resolved to make more angels or more natures of things, He
would have impressed more intelligible species in the angelic minds; as a builder who, if
he had intended to build a larger house, would have made larger foundations. Hence, for
God to add a new creature to the universe, means that He would add a new intelligible
species to an angel.

ARTICLE 3
Whether an angle knows God by his own natural principles?
Objection 1
It would seem that the angels cannot know God by their natural principles. For
Dionysius says (Div. Nom. i) that God "by His incomprehensible might is placed above
all heavenly minds." Afterwards he adds that, "since He is above all substances,
He is remote from all knowledge."
Objection 2
Further, God is infinitely above the intellect of an angel. But what is
infinitely beyond cannot be reached. Therefore it appears that an angel cannot know God by
his natural principles.
Objection 3
Further, it is written (1 Cor. 13:12): "We see now through a glass in a
dark manner; but then face to face." From this it appears that there is a twofold
knowledge of God; the one, whereby He is seen in His essence, according to which He is
said to be seen face to face; the other whereby He is seen in the mirror of creatures. As
was already shown (Q12, ARTICLE 4), an angel cannot have the former knowledge by his
natural principles. Nor does vision through a mirror belong to the angels, since they do
not derive their knowledge of God from sensible things, as Dionysius observes (Div. Nom.
vii). Therefore the angels cannot know God by their natural powers.
On the contrary
On the contrary, The angels are mightier in knowledge than men. Yet men can know God
through their natural principles; according to Rm. 1:19: "what is known of God is
manifest in them." Therefore much more so can the angels.
Body
I answer that, The angels can have some knowledge of God by their own principles. In
evidence whereof it must be borne in mind that a thing is known in three ways: first, by
the presence of its essence in the knower, as light can be seen in the eye; and so we have
said that an angel knows himself---secondly, by the presence of its similitude in the
power which knows it, as a stone is seen by the eye from its image being in the
eye---thirdly, when the image of the object known is not drawn directly from the object
itself, but from something else in which it is made to appear, as when we behold a man in
a mirror.
To the first-named class that knowledge of God is likened by which He is seen through His
essence; and knowledge such as this cannot accrue to any creature from its natural
principles, as was said above (Q12, ARTICLE 4). The third class comprises the knowledge
whereby we know God while we are on earth, by His likeness reflected in creatures,
according to Rm. 1:20: "The invisible things of God are clearly seen, being
understood by the things that are made." Hence, too, we are said to see God in a
mirror. But the knowledge, whereby according to his natural principles the angel knows
God, stands midway between these two; and is likened to that knowledge whereby a thing is
seen through the species abstracted from it. For since God's image is impressed on the
very nature of the angel in his essence, the angel knows God in as much as he is the image
of God. Yet he does not behold God's essence; because no created likeness is sufficient to
represent the Divine essence. Such knowledge then approaches rather to the specular kind;
because the angelic nature is itself a kind of mirror representing the Divine image.
Reply to Objection 1
Dionysius is speaking of the knowledge of comprehension, as his words
expressly state. In this way God is not known by any created intellect.
Reply to Objection 2
Since an angel's intellect and essence are infinitely remote from God, it
follows that he cannot comprehend Him; nor can he see God's essence through his own
nature. Yet it does not follow on that account that he can have no knowledge of Him at
all: because, as God is infinitely remote from the angel, so the knowledge which God has
of Himself is infinitely above the knowledge which an angel has of Him.
Reply to Objection 3
The knowledge which an angel has of God is midway between these two kinds
of knowledge; nevertheless it approaches more to one of them, as was said above.