"And when I desired to meditate on my God, I did not know what to think of but a huge extended body -- for what did not have bodily extension did not seem to me to exist -- and this was the greatest and almost the sole cause of my unavoidable errors."
-The Confessions of St. Augustine, Book V Chapter X
"For I had been both impious and rash in this, that I condemned by pronouncement what I ought to have learned by inquiry. For thou, O Most High, and most near, most secret, yet most present, who does not have limbs, some of which are larger and some smaller, but who art wholly everywhere and nowhere in space, and art not shaped by some corporeal form: thou didst create man after thy own image and, see, he dwells in space, both head and feet."
-Book VI Chapter III
"...My desire was to have other things as clear as this, whether they were physical objects, which were not present to my senses, or spiritual objects, which I did not know how to conceive of except in physical terms."
-Book IV Chapter IV
Imagination is fundamentally related to sensation. The activity of the human intellect is also essentially related to sensation, but it is not related qua intellect but qua human. Both the angelic and divine intellects have operations apart from sensation and are superior to the human intellect, a superiority which, in fact, partly consists in separation from sensation.
As a power that is related to sensation, imagination is essentially related to matter and material existence. The imagination, then, can only assist our understanding inasmuch as matter is a principle of the object understood. As we climb the ladder or hierarchy of being toward things not composed of form and matter or as we approach metaphysics in general, the imagination can become, at least, a hindrance and, at most, a dangerous cause of error.