And [Aristotle] says that the very desire to attentively lay out difficult and obscure things and give their cause, and to inquire into everything and leave aside nothing, will perhaps be seen as a sign either of great stupidity that causes one to be unable to distinguish between the easy and the difficult, or else as a sign of "great hastiness," i.e., of great presumption, that causes a man not to know the measure of his capability for investigating the truth. But although some deserve rebuke on this point, it is not a just thing to condemn all alike; rather we ought first to look at two things.
(1) We must look at the cause that moves a man to speak of such things, whether he is doing it out of love for the truth (ex amore veritatis) or in order to show off his cleverness (ad ostentationem sapientiae)? (2) One ought to consider how he governs himself in believing what he asserts, whether he has a weak certainty about them according to the common human way (secundum communem hominum modum), or does he know them firmly, i.e., beyond the common human way? When, therefore, a person can attain to a knowledge of necessary causes more certainly than the common human way, he who finds such necessities ought to receive our thanks rather than our rebuke.
Thomas Aquinas. In De caelo, lib. 2 l. 7 n. 4. The translation is mine and is quick and loose, so it should be taken with a grain of salt.
