Owen Thomas professes: "Tradition can also mean what the Roman
Catholic Church calls the secret tradition, namely, that part of the
apostolic tradition which was not committed to writing, but was handed down orally by the apostolic bishops." He adds: "There is no historical foundation for the existence of such a tradition."
The declaration at the Council of Trent in 1564 concerning "the unwritten traditions" possibly confirms Thomas' interpretation of the Latin view concerning what has been handed down (i.e., tradition). Did not Trent also decide that the Bible does not contain all things necessary for salvation? Or maybe I should say, all things formally necessary for salvation. From one Catholic source, we read:
"The Roman Church, however, does not depend solely on literary and
historical evidence; it depends on its own consciousness of its belief,
and it must be admitted that the analysis of this consciousness can be
subtle" (John McKenzie, The Roman Catholic Church, p. 212)
The same book also states: "The Council of Trent admitted frankly that
the Roman tradition contains propositions which cannot be found in the Bible.
It countered the Protestant charge by asserting itself, so to speak; it denied that either in the Bible or in its own traditions is there any affirmation
that the Bible is the sole source of revealed truth . . . An unresolved
question in contemporary theology is whether the Council of Trent meant
that Scripture and tradition are two sources of revealed truth.
Certainly the Council did not mean that they are two unrelated sources.
The weight of opinion in Roman theology since the Council of Trent has
been that the Council did mean two sources. The Bible is superior in
dignity, but tradition is superior in completeness" (McKenzie, 212-213).
Of course, Catholics have told me that Owen Thomas' depiction of Catholic tradition is not correct: they say Catholic tradition is not secret or hidden. Below, I include the statement from Trent (Session IV):
This [Gospel], of old promised through the Prophets in the Holy Scriptures, our Lord Jesus Christ, the Son of God, promulgated first with His own mouth, and then commanded it to be preached by His Apostles to every creature as the source at once of all saving truth and rules of conduct.
It also clearly perceives that these truths and rules are contained in the written books and in the unwritten traditions, which, received by the Apostles from the mouth of Christ Himself, or from the Apostles themselves, the Holy Ghost dictating, have come down to us, transmitted as it were from hand to hand.
Following, then, the examples of the orthodox Fathers, it receives and venerates with a feeling of piety and reverence all the books both of the Old and New Testaments, since one God is the author of both; also the traditions, whether they relate to faith or to morals, as having been dictated either orally by Christ or by the Holy Ghost, and preserved in the Catholic Church in unbroken succession.