“Since faith rests upon infallible truth, and since the contrary of a truth can never be demonstrated, it is clear that the arguments brought against faith cannot be demonstrations, but are difficulties that can be answered.”

“[I]t is to be borne in mind, in regard to the philosophical sciences, that the inferior sciences neither prove their principles nor dispute with those who deny them, but leave this to a higher science; whereas the highest of them, viz. metaphysics, can dispute with one who denies its principles, if only the opponent will make some concession; but if he concede nothing, it can have no dispute with him, though it can answer his objections. Hence Sacred Scripture, since it has no science above itself, can dispute with one who denies its principles only if the opponent admits some at least of the truths obtained through divine revelation; thus we can argue with heretics from texts in Holy Writ, and against those who deny one article of faith, we can argue from another. If our opponent believes nothing of divine revelation, there is no longer any means of proving the articles of faith by reasoning, but only of answering his objections — if he has any — against faith. Since faith rests upon infallible truth, and since the contrary of a truth can never be demonstrated, it is clear that the arguments brought against faith cannot be demonstrations, but are difficulties that can be answered.”

“The medievals loved to say that God wrote two books: nature and Scripture. And since he is the author of both books, and since this Teacher never contradicts himself, these two books never contradict each other. And since this God who never contradicts himself also gave us the two truth detectors, faith and reason, it follows that faith and reason, properly used, never contradict each other. Therefore, all heresies are contrary to reason. Not all the truths of faith can be proved by reason, but all arguments against the truths of faith can be disproved by reason.”

“Faith is the truth of passion. Since no passion is more true than another, faith is the truth of nothing.”

“If you've got the truth you can demonstrate it. Talking doesn't prove it.”

“Do not think that we say that these things are only to be received by faith, but also that they are to be asserted by reason. For indeed it is not safe to commit these things to bare faith without reason, since assuredly truth cannot be without reason.”