APPENDIX - S. VINCENT OF LERINS
"Whilst often making very earnest and diligent inquiries of many excellent, holy, and learned men, as to how and by what means I might securely -- and by some, so to say, general and normal way -- discern the truth of Catholic faith from the falsity of heretical pravity, I usually received this answer from them all, viz., that if I or any one else wished to find out the deceits of the heretics who were daily springing up, escape their snares, and remain safe and sound in the true faith, one must, with God's assistance, defend and preserve his faith in a twofold manner: first, by the authority of the Divine law, and secondly by the tradition of the Catholic Church... But since by reason of the very profundity of Holy Scripture, all do not understand it in one and the same sense, but divers men diversely; one interpreting the same words this way, and another that; so that, to one's thinking, so many men, so many opinions may be gathered from it... Consequently it is of all importance, in order not to be led away into the windings of every sort of error, to hold fast to the line of scriptural interpretation that is according to the rule of the ecclesiastical and Catholic sense. Within the Catholic Church itself, too, we should take great care to hold that which has been believed everywhere, and always, and by all (quod ubique, quod semper, quod ab omnibus creditum est). For this is really and properly Catholic, as the very meaning of the words and reason show, and in a general way, comprises everything. This, too, will be in fact the case, if we follow universality, antiquity, and common consent. Universality, then, we shall follow, if we confess that one faith as true, which the whole Church throughout the whole world confesses; Antiquity, if in no way we depart from those sentiments which it is manifest our holy elders and Fathers held and generally approved (celebrasse); Common consent, in fine, if we follow what were in antiquity the definitions and judgments (sententias) of all, or, at any rate, nearly all the priests and teachers alike."*
Later on, in his Second Commonitory, he says:
"We have to pay most earnest heed to two things, unto which all those that will not be heretics, must of necessity cling fast. The first is to see what has been decreed in old time by all the priests of the Catholic Church with authority of a General Council. And secondly, should some new question arise, about which no decree is to be found, we must then have recourse to the judgments of the Holy Fathers," etc.+
Hence we see that S. Vincent when in doubt whether doctrines, not yet defined by the Church, were Catholic or not, made it his rule to consult the writings of the Fathers. If he found from their testimony that a certain doctrine had been believed in the Church ubique, that is, by faithful living in all parts of Christendom; semper, that is, from the Apostles' days to his own time; ab omnibus, that is, by all those generally who were regarded as sound Catholics, or rather, what was held by the great majority of bishops and doctors, he at once concluded that such a doctrine was undoubtedly a genuine doctrine of Christian revelation, since it had been believed everywhere, always, and by all.
But because all doctrines that have been believed, ubique, semper, et ab omnibus, are undoubtedly genuine Christian doctrines, it by no means follows that these are the only genuine Christian doctrines; nor, as we shall see, did S. Vincent himself thus conclude.
Moreover, he goes on to qualify this general and ordinary rule (quasi generalis et regularis via) that he had laid down. He supposes the case of heresy infecting not only some portion of the Church, but going about to corrupt the whole Church altogether; and of our seeing in antiquity that individual teachers, cities, and provinces have fallen into error. Here, he says, we must adhere to what the universal Church has in Council decreed.