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 (Question [50], Article [4]; Question [55], 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.