Recall that you are spatio-temporally continuous with a blastocyst. Within that microscopic you, there were and remain all the DNA instructions for what you physically became. Your body was once "virtually"—in the classical sense of that term derived from the Latin virtus: "power"—what it is now. Indeed, your body now is the same body as that blastocyst; the difference is that what "it" contained were mostly the codes for producing what you now see (and a lot of what you don't see). The difference is one of development not identity.
The Catholic Faith is like that. That the authoritative documents of the Catholic Church, such as the Catechism of the Catholic Church, are collectively much, much longer than the New Testament is not a sign of undue human elaboration of the Word of God. The primordial Word of God is God the Son and thus God himself: "In the beginning was the Word." What's more often called the "Word", embodied in the preaching of the Apostles, the Bible, Sacred Tradition, and dogma, is but the transmission of truths from and about the primordial Word. Such media of transmission and elaboration are but the making explicit of much that was implicit in the primitive kerygma. That entails development fueled by explanation. Thus the Apostles would not have known what the Council of Nicaea meant by saying that the Son is homoousios with the Father, yet that phrase signified an authentic, organic development of what they did preach. The basic deposit of faith was indeed "delivered once for all to the saints" from the start; but it took centuries of meditation, heresy, and definition to bring forth to maturity much that was inchoate. The right codes were always there, but what contained them needed time and nourishment for the growth they have regulated.
The analogy of articulation by growth from a small beginning derives of course from the great John Henry Newman's Essay on the Development of Christian Doctrine (revised edition: 1878). What Newman lacked was the DNA analogy. He didn't know that the seed, his favorite simile for the deposit of faith, contained the actual instructions for developing the mature plant, just as the embryo does for the mature person. Yet perhaps the plant analogy is better for what happened to the Church.
Christianity started as a Jewish movement, and its first-generation leadership was entirely Jewish. But around AD 50, that began to change radically. The first major controversy in the young Church was whether Gentile converts had to be circumcised and observe other requirements of Jewish law in order to belong to the Church. St. Paul had never thought so, but the mother Church in Jerusalem wasn't always so sure. Even so, the "Council of Jerusalem" (see Acts 15), with the Apostle Peter and James "the brother of the Lord" presiding, ended up essentially agreeing with Paul and endorsing his ministry accordingly. That had two immediate effects. It facilitated an explosion of adult Gentile converts, which would probably never have occurred if penile mutiliation had been made a condition of Church membership; and it cemented permanently the enmity of the non-Christian Jewish leadership. Over the next decade, Christians were decisively expelled from synagogues everywhere. By the mid-sixties, Peter, Paul, and James had been martyred, the first two at Rome and the last at Jerusalem; the Gospel according to Mark, the first of the four, was written from Rome; and the Jews in Palestine launched a war of rebellion againt the Romans which, though successful at first, ended in the destruction of the Second Temple and the slaughter of much of the population. Early in the war, the Jerusalem Church had fled to the desert; after the war, it became a rural backwater, eventually dividing into Nazarenes and Ebionites. Within a generation of the Council of Jerusalem, the Church had morphed into a primarily Gentile thing that everybody sharply distinguished from an increasingly beleaguered Judaism. The seedling church had been transplanted, seeding still other churches, away from its original ground. And that is where it was destined to grow into a universal religion, to be articulated as much in terms of Greek metaphysics as Jewish messianism.
I have come to suspect that the division within Christendom into Catholicism, Orthodoxy, and Protestantism can be explained largely in terms of where people stand about ecclesial and doctrinal development. Most Protestants, invoking sola scriptura, don't think doctrinal development beyond the Bible necessary and seek a primitive, more "authentic" church order. Most Orthodox, invoking the Fathers and the Seven Ecumenical Councils as well, don't think development beyond the eighth or ninth century necessary; only the Catholic Church keeps on developing doctrine and molting her disciplinary structures while retaining her distinctive cohesion. Perhaps I remain Catholic, despite all the Church's problems, because I don't believe substantive doctrinal and disciplinary development can be frozen any more than it ought to be—so long as it follows the model I've analogized and is thus neither negation of nor addition to the deposit of faith. The two other main branches of Christianity thus strike me as too "fundamentalist," for want of a better word. They just disagree about the size and age of the fundament. I agree there's a fundament: it includes everything other Christians say it does. But it is also the basis of further, authentic development. Physical growth may stop after late adolescence, but spiritual and intellectual growth should never stop. Only by continued maturation does the Church remain forever young.
