While one man can discover a certain thing by himself, another is never able to understand it, even if taught by means of all possible expressions and metaphors, and during a long period; his mind can in no way grasp it, his capacity is insufficient for it. - Maimonides
Further, there are things of which the mind understands one part, but remains ignorant of the other; and when man is able to comprehend certain things, it does not follow that he must be able to comprehend everything. - Maimonides
It is good to know what a man is, and also what the world takes him for. But you do not understand him until you have learnt how he understands himself. - F. H. Bradley