[77] [cap.17] And the most visible proof of this migration in which the mind quitted astronomy and the doctrines of the Chaldaeans, is this. For it is said in the scriptures that the very moment that the wise man quitted his abode, "God appeared unto Abraham," [19] to whom, therefore, it is plain that he was not visible before, when he was adhering to the studies of the Chaldaeans, and attending to the motions of the stars, not properly comprehending any nature whatever, which was well arranged and appreciable by the intellect only, apart from the world and the essence perceptible by the outward senses.