The way to wisdom is therefore not like that of a man rising from the water into the air, in which, in the moment of rising above the surface of the water, he suddenly breathes freely, but, like that of a man proceeding from darkness into light, on whom more light gradually shines as he advances. So long, therefore, as this is not fully accomplished, we speak of the man as of one going from the dark recesses of a vast cavern towards its entrance, who is more and more influenced by the proximity of the light as he comes nearer to the entrance of the cavern; so that whatever light he has proceeds from the light to which he is advancing, and whatever darkness still remains in him proceeds from the darkness out of which he is emerging.
Augustine, Letter 167 (chapter 3/section 13) to Jerome.
