In section §8 of its Dogmatic Constitution on Divine Revelation, Dei Verbum, the Second Vatican Council said (emphasis added; notes omitted):
And so the apostolic preaching, which is expressed in a special way in the inspired books, was to be preserved by an unending succession of preachers until the end of time. Therefore the Apostles, handing on what they themselves had received, warn the faithful to hold fast to the traditions which they have learned either by word of mouth or by letter (see 2 Thess. 2:15), and to fight in defense of the faith handed on once and for all (see Jude 1:3). Now what was handed on by the Apostles includes everything which contributes toward the holiness of life and increase in faith of the peoples of God; and so the Church, in her teaching, life and worship, perpetuates and hands on to all generations all that she herself is, all that she believes.
This tradition which comes from the Apostles develops in the Church with the help of the Holy Spirit. For there is a growth in the understanding of the realities and the words which have been handed down. This happens through the contemplation and study made by believers, who treasure these things in their hearts (see Luke, 2:19, 51) through a penetrating understanding of the spiritual realities which they experience, and through the preaching of those who have received through episcopal succession the sure gift of truth. For as the centuries succeed one another, the Church constantly moves forward toward the fullness of divine truth until the words of God reach their complete fulfillment in her.
The words of the holy fathers witness to the presence of this living tradition, whose wealth is poured into the practice and life of the believing and praying Church. Through the same tradition the Church's full canon of the sacred books is known, and the sacred writings themselves are more profoundly understood and unceasingly made active in her; and thus God, who spoke of old, uninterruptedly converses with the bride of His beloved Son; and the Holy Spirit, through whom the living voice of the Gospel resounds in the Church, and through her, in the world, leads unto all truth those who believe and makes the word of Christ dwell abundantly in them (see Col. 3:16).From that, the Catholic theologians to whom I've already referred rightly conclude that it is the official teaching of the Catholic Church that there is such a thing as development of doctrine, in the sense specified. At the same time, it is understood that such development does not entail addition to the deposit of faith, but only a collective "growth" in the "understanding" thereof, which is expressed inter alia in such irreformable dogmatic formulations as the Church occasionally sees fit to issue. What "develops" is not divine revelation itself, which was given in its fullness to the Apostles and which, in its public and binding aspects, ceased with the death of the last Apostle; rather, development takes the form of greater clarity and explicitness in our formulations of the truth contained in the "faith-once-delivered," and therefore a clearer understanding of that faith.
Now in a comment on my earlier post, Fr. Robert Hart of the Anglican Continuum wrote thus:
Development of Doctrine cannot actually mean that the Council of Nicea finally gave us truth never before known, anymore than it can contradict the fact that Saint Basil had only to draw from sources that were (in his time) ancient to teach about the Holy Spirit (scripture and liturgy mainly). So, the new and extreme view of D o D that some have expressed here is every bit as much of an innovation, and a danger, as sola scriptura, in fact the opposite error. The idea that the doctrine of the Trinity, which includes the revelation of Christ's two natures and the Personhood and divinity of the Holy Spirit, has not been the doctrine of the Church from its earliest generation, is an argument I expect from Jehovah's Witnesses, not from Catholics. If Fr. Pat accidentally exposed this radical new definition (shall we say, this development of the Development of Doctrine theory) then I am glad.
Referring to Reardon, Hart concludes:
Still, D o D was not his target.
I have already conceded the point that Reardon did not intend to reject the very idea of DD . My concern here is with what Reardon and Hart actually do.
As is so often the case, a distinction is badly needed. It is one thing to say that the realities expressed by the doctrine of the Trinity were known to the Church before the Council of Nicaea, which is clearly true. Anybody who denies that must accordingly deny that God revealed to the Apostles all that he intended to reveal to the Church, which would be incompatible with traditional Christianity. But it is another thing altogether to say that the doctrine of the Trinity itself was known to the Church all along before Nicaea, which is equally clearly false. What the Church had received and "handed on" in the beginning was materially the same as the doctrine of the Trinity, but not formally. Thus, the formal definitions propounded by Nicaea I and the other, subsequent ecumenical councils of the first millennium, which collectively comprise the doctrine of the Trinity, made more explicit what had been less so in the earlier sources, without in any way discovering truth not somehow contained in those sources.
Now the distinction I've drawn, it seems to me, is exactly what some of Reardon's statements fail to observe. Thus, concerning Nicaea I, he wrote:
It is important to observe that the use of the word homoousios did not “clarify” anything about God. It added no new light or intelligibility to what was already revealed in Jesus of Nazareth. The purpose of dogmatic definitions is not to throw further light on what is, after all, the fullness of revealed truth. The purpose of dogmatic definitions is, rather, to confound heretics. Dogma serves to “focus” revelation in the sense of declaring what is “not in line” with revelation. Of itself, however, a dogma adds nothing new. Hence, it is wrong to imagine that Nicaea’s declaration clarified revealed truth. It did not. Nicaea told us absolutely nothing beyond what the Apostles had declared. Indeed, the Nicene Fathers went to some lengths to insist on this point.
If all that's meant by the above that Nicaea's formulations did not contain any truth "beyond what the Apostles declared," that is true as I've already indicated. But if it is meant that Nicaea's formulations did not express truth more clearly than the Apostles had, that is false. And that's just what Reardon seems to say.
Thus he says that the purpose of dogmatic definitions is not to "clarify" the faith but to "confound heretics." But how, exactly, are heretics to be confounded by statements that are no clearer than the original profession? The point of definitions such as Nicaea's is to be more specific about the unchanging truth, in such a way as to make clearer that aspect of the truth which the heretics deny. That is why, apropos of Jesus Christ, Nicaea added to the Apostles' Creed the following:"eternally begotten of the Father: God from God, light from light, true God from true God, begotten not made, of the same substance as (homoousios) the Father." The heresy of Arianism would not have become so widespread if it had been clear to most Christians that Arianism was incompatible with what the Church had always believed. The main purpose of Nicaea I was, accordingly, to make clear precisely what had not been so clear. And it did so precisely by formulating the faith-once-delivered in new terms that did not augment its content, but only its expression, and therefore the understanding of it.
What had led me to make my initial error about Reardon's intentions was that the point I've just made seems so obvious to me that anybody who denies that Nicaea "clarified revealed truth"—which is just what Reardon did deny—is denying that doctrine develops in the way I've been maintaining. So, since he seems to uphold some idea of DD, I'd like to know what it is. I haven't seen it thus far.