Humani Generis §18

¹⁸ Unfortunately these advocates of novelty easily pass from despising scholastic theology to the neglect of and even contempt for the Teaching Authority of the Church itself, which gives such authoritative approval to scholastic theology. This Teaching Authority is represented by them as a hindrance to progress and an obstacle in the way of science. Some non-Catholics consider it as an unjust restraint preventing some more qualified theologians from reforming their subject. And although this sacred Office of Teacher in matters of faith and morals must be the proximate and universal criterion of truth for all theologians, since to it has been entrusted by Christ Our Lord the whole deposit of faith - Sacred Scripture and divine Tradition - to be preserved, guarded and interpreted, still the duty that is incumbent on the faithful to flee also those errors which more or less approach heresy, and accordingly "to keep also the constitutions and decrees by which such evil opinions are proscribed and forbidden by the Holy See," is sometimes as little known as if it did not exist. What is expounded in the Encyclical Letters of the Roman Pontiffs concerning the nature and constitution of the Church, is deliberately and habitually neglected by some with the idea of giving force to a certain vague notion which they profess to have found in the ancient Fathers, especially the Greeks. The Popes, they assert, do not wish to pass judgment on what is a matter of dispute among theologians, so recourse must be had to the early sources, and the recent constitutions and decrees of the Teaching Church must be explained from the writings of the ancients.