29 For, the teachings of Thomas on the true meaning of liberty, which at this time is running into license, on the divine origin of all authority, on laws and their force, on the paternal and just rule of princes, on obedience to the higher powers, on mutual charity one toward another-on all of these and kindred subjects-have very great and invincible force to overturn those principles of the new order which are well known to be dangerous to the peaceful order of things and to public safety. In short, all studies ought to find hope of advancement and promise of assistance in this restoration of philosophic discipline which We have proposed. The arts were wont to draw from philosophy, as from a wise mistress, sound judgment and right method, and from it, also, their spirit, as from the common fount of life. When philosophy stood stainless in honor and wise in judgment, then, as facts and constant experience showed, the liberal arts flourished as never before or since; but, neglected and almost blotted out, they lay prone, since philosophy began to lean to error and join hands with folly. Nor will the physical sciences themselves, which are now in such great repute, and by the renown of so many inventions draw such universal admiration to themselves, suffer detriment, but find very great assistance in the restoration of the ancient philosophy. For, the investigation of facts and the contemplation of nature is not alone sufficient for their profitable exercise and advance; but, when facts have been established, it is necessary to rise and apply ourselves to the study of the nature of corporeal things, to inquire into the laws which govern them and the principles whence their order and varied unity and mutual attraction in diversity arise. To such investigations it is wonderful what force and light and aid the Scholastic philosophy, if judiciously taught, would bring.
Source: Aeterni Patris (Vatican.va)