Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter LXV

Chapter LXV.—Fallacy of Imagination.

“In short, that you may receive the faith of the matter; concerning Jerusalem, which I had often seen, I told my brother what places and what gatherings of people I had seemed to myself to see.  But also concerning Cæsarea, which I had never seen, I nevertheless contended that it was such as I had conceived it in my mind and thought.  But when I came hither, and saw nothing at all like to those things which I had seen in phantasy, I blamed myself, and observed distinctly, that I had assigned to it gates, and walls, and buildings from others which I had seen, taking the likeness in reality from others.  Nor indeed can any one imagine anything new, and of which no form has ever existed.  For even if any one should fashion from his imagination bulls with five heads, he only forms them with five heads out of those which he has seen with one head.  And you therefore, now, if truly you seem to yourself to perceive anything with your thought, and to look above the heavens, there is no doubt but that you imagine them from those things which you see, placed as you are upon the earth.  But if you think that there is easy access for your mind above the heavens, and that you are able to conceive the things that are there, and to apprehend knowledge of that immense light, I think that for him who can comprehend these things, it were easier to throw his sense, which knows how to ascend thither, into the heart and breast of some one of us who stand by, and to tell what thoughts he is cherishing in his breast.  If therefore you can declare the thoughts of the heart of any one of us, who is not pre-engaged in your favour, we shall perhaps be able to believe you, that you are able to know those things that are above the heavens, although these are much loftier.”