[Etienne] Gilson [...] retorted that, far from poisoning philosophy with a sleeping potion, faith illuminates from above the path reason would follow in any event if it only had a map and a flashlight. Philosophy’s goal has always been the truth, but it has to grope because it can’t see that far ahead. To understand Gilson’s thesis, think of it this way: When one is first studying algebra, say, especially when using one of those teach-yourself books, the problems are given in the front to work out on one’s own, with the answers keyed at the back. Now, if one works out a problem only to discover from the answer key that one got it wrong, one knows then and there that one was wrong but not how or why. For that one needs to go back and retrace one’s steps and see how one can rationally prove both the false step and the true path.
But as Adler says in his Aquinas Lecture: “I owe to a friend the insight that it is not possible to be a good disciple of a false doctrine; but it must be added that it is not easy to be the good disciple of a true one.”