Some assert boldly: "There is no such thing as a catholic principle."
I cannot agree with this. Not when reading the Lutheran Symbols and the history of the Churches of the Augsburg Confession.
Long have Lutherans been aware of the liturgical effects of the catholic principle - for it is ennunciated with utter clarity in AC XV. "Our churches teach that ceremonies ought to be observed that may be observed without sin. Also, ceremonies and other practices that are profitable for tranquility and good order in the Church (in particular, holy days, festivals, and the like) ought to be observed." The fact that this is in the doctrinal section of the AC (not the abuse section) and begins with "our churches teach" elevates the contained liturgical catholic prinicple to a doctrine of the Church of the Augsburg Confession.
But does it stop with the liturgy?
What meaning do those who deny the catholic principle attribute to the words that close out the doctrinal section of the AC? "As can be seen, there is nothing that varies from the Scripture, or from the Church universal, or from the Church of Rome, as known from its writers." (Summary 1)
I think that the trouble arises for these folks because they persist in conceiving of Scripture and Tradition in the Roman terms: two related but differing sources from which doctrine may be drawn. They are afraid that what is not in Scripture but is found in some Tradition will be foisted upon the Church in the manner of Trent. But this is to miss the true understanding of Tradition, which is not a separate and independent source of doctrine, but is precisely *the correct understanding of the Scriptures* which is given by the Holy Spirit and lives within the Church.
To read the Scriptures *with the Church* and according to her own understanding of them - this is Tradition. And this is something that the Lutheran Confessors never conceived of the Church being without. "Even as He calls, gathers, *enlightens*, and sanctifies *the whole Christian Church* and keeps it with Jesus Christ in the one, true faith."
The bugaboo is always the perpetual virginity of the Blessed Virgin Mary. The simple fact is that the Church's read of the Scriptures sees this as completely in harmony with the Sacred Scriptures and hinted at in them by numerous types. The Lutheran Symbols assert this doctrine not only in the famous Latin of the SA from the BOC of 1584, but also in the German BOC of 1580, under SD VIII:24, where we read: "Therefore she is truly the Mother of God and yet has remained a virgin." Even Sasse freely admits that the Symbols here confess the perpetual virginity.
Walther, holding firmly to the catholic principle that recognizes in the Lutheran Symbols a definitive form of the Tradition - that is, the church's correct understanding of the Sacred Scriptures - affirmed in the Colloquey with Iowa, that this is a doctrine and that he holds to it. When challenged for his Scripture to back it up, he ruled the question out of order. Why? Because to him a Lutheran by definition is one who accepts the Symbols as a correct exposition of the Scriptures.
So the whole notion of the "catholic principle" is but another way of saying "quia." A whole and complete quia, mind you, and not the broken quia that says: "I believe everything in the Symbols for which *I* happen to find a justification in the Scriptures" for that of course confesses nothing at all.