The Love of the Studious Mind, that Is, of One Desirous to Know, is Not the Love of a Thing Which It Does Not Know
1 Let us now proceed, then, in due order, with a more exact purpose, to explain this same point more thoroughly. And first, since no one can love at all a thing of which he is wholly ignorant, we must carefully consider of what sort is the love of those who are studious, that is, of those who do not already know, but are still desiring to know any branch of learning. Now certainly, in those things whereof the word study is not commonly used, love often arises from hearsay, when the reputation of anything for beauty inflames the mind to the seeing and enjoying it; since the mind knows generically wherein consist the beauties of corporeal things, from having seen them very frequently, and since there exists within a faculty of approving that which outwardly is longed for.
And when this happens, the love that is called forth is not of a thing wholly unknown, since its genus is thus known. But when we love a good man whose face we never saw, we love him from the knowledge of his virtues, which virtues we know [abstractly] in the truth itself. But in the case of learning, it is for the most part the authority of others who praise and commend it that kindles our love of it; although nevertheless we could not burn with any zeal at all for the study of it, unless we had already in our mind at least a slight impression of the knowledge of each kind of learning.
For who, for instance, would devote any care and labor to the learning of rhetoric, unless he knew before that it was the science of speaking? Sometimes, again, we marvel at the results of learning itself, which we have heard of or experienced; and hence burn to obtain, by learning, the power of attaining these results. Just as if it were said to one who did not know his letters, that there is a kind of learning which enables a man to send words, wrought with the hand in silence, to one who is ever so far absent, for him in turn to whom they are sent to gather these words, not with his ears, but with his eyes; and if the man were to see the thing actually done, is not that man, since he desires to know how he can do this thing, altogether moved to study with a view to the result which he already knows and holds?
So it is that the studious zeal of those who learn is kindled: for that of which any one is utterly ignorant, he can in no way love.
Source: On the Holy Trinity (New Advent)