Aeterni Patris §16

¹⁶ Although these words seem to bear reference solely to Scholastic theology, nevertheless they may plainly be accepted as equally true of philosophy and its praises. For, the noble endowments which make the Scholastic theology so formidable to the enemies of truth-to wit, as the same Pontiff adds, "that ready and close coherence of cause and effect, that order and array as of a disciplined army in battle, those clear definitions and distinctions, that strength of argument and those keen discussions, by which light is distinguished from darkness, the true from the false, expose and strip naked, as it were, the falsehoods of heretics wrapped around by a cloud of subterfuges and fallacies"(33) - those noble and admirable endowments, We say, are only to be found in a right use of that philosophy which the Scholastic teachers have been accustomed carefully and prudently to make use of even in theological disputations. Moreover, since it is the proper and special office of the Scholastic theologians to bind together by the fastest chain human and divine science, surely the theology in which they excelled would not have gained such honor and commendation among men if they had made use of a lame and imperfect or vain philosophy.