For although those who are enlightened by the true philosophy sometimes think that pleasure is not caused by external objects, and although this knowledge can to some extent lead them to recognize and love God in all things, nevertheless, since his sin the rational part of man is so feeble, and his senses and imagination have so much power over his mind, that they soon corrupt his heart if he does not deprive himself, according to the counsel of the Gospel, of all things that do not of themselves lead to God.