“Philosophy ... is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.”

“[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.”

“Different ‘philosophies’ represent nothing but methods of evaluation, which may lead to empirical mis-evaluation if science and empirical facts are disregarded.”

“We believe that it is possible for scientific work to gain some knowledge about the reality of the world, by means of which we can increase out power and in accordance with which we can arrange our life. If this belief is an illusion, then we are in the same position as you. But science has given us evidence by its numerous and important successes that it is no illusion.”

“... always keep in mind that an article of faith is not something that the faithful assume. Faith, for those who have it, is the most certain form of knowledge, not a tentative opinion.”

“Science has nothing to do with any dogma. Science ceases to exist when there is a dogma.”