C.S. Lewis, the famous Anglican writer, once wrote:
The Catholic Church, in agreement with Lewis, defines doctrinal development as a growth of depth and clarity in the understanding of the truths of divine revelation. It is important to understand that the substantial or essential truths at the core of each doctrine remain unchanged. Only the subjective grasp of men increases. This increase is the result of the prayerful reflection of the Church, theological study and research (often occasioned by heretical challenges), practical experience, and the collective wisdom of the Church's bishops and popes, especially when joined in Ecumenical Councils.
The very possibility of progress demands that there should be an unchanging element . . . the positive historical statements made by Christianity have the power . . . of receiving, without intrinsic change, the increasing complexity of meaning which increasing knowledge puts into them.
(God in the Dock, Eerdmans, Grand Rapids, MI, 1970, 44-47)
Like many Christian doctrines, the idea of doctrinal development is based on much implicit or indirect scriptural evidence. The best indications are perhaps Mt. 5:17, 13:31-2, Jn. 14:26, 16:13, 1 Cor. 2:9-16, Gal. 4:4, Eph. 1:10, 4:12-15. Furthermore, doctrine clearly develops within Scripture ("progressive revelation"). Examples: doctrines of the afterlife, the Trinity, the Messiah (eventually revealed as God the Son), the Holy Spirit (Divine Person in the New Testament), the equality of Jews and Gentiles, bodily resurrection, sacrifice of lambs evolving into the sacrifice of Christ, etc. Not a single doctrine emerges in the Bible complete with no further need of development.
In general, whenever Scripture refers to the increasing knowledge and maturity of Christians and the Church, an idea very similar to doctrinal development is present. Holy Scripture, then, is in no way hostile to development. It is only Protestant presuppositions - not always so "biblical" - which preclude development for fear of "excess."
The Canon of Scripture itself is an example of developing doctrine. The New Testament never informs us which books comprise itself, and its Canon (final list of books) took about 360 years to reach its final form (at the Council of Carthage in 397). For instance, the books of Hebrews, James, 2 Peter, 2 and 3 John, Jude, and Revelation were not widely accepted by the Church until 350 A.D.!
And books such as Barnabas and 1 and 2 Clement were considered Scripture by many at the same time (for example, the manuscripts Codex Sinaiticus and Codex Alexandrinus). Of the 27 New Testament books, 14 were not mentioned at all until around 200 A.D., including Acts, 2 Corinthians, Galatians and Colossians.
On what grounds, then, can we receive the Canon today except on the authority of the Church in the 5th century? These facts cause insuperable problems for Protestantism and its guiding principle of "Scripture Alone," but are not a difficulty in the least for Catholics, who believe in Tradition, Church Authority, and development - all crucial elements in the very human process of selection of the biblical Canon.
It is plain silly (not to mention insufferably arrogant) to assert, as did Luther and especially Calvin, that the knowledge of what books constitute Scripture is attained simply by an intuitive and subjective inkling within each Spirit-filled person. If the early Church had such a difficult time determining what was and was not Scripture, how could Calvin 15 centuries later claim that it was altogether simple for him and every other sincere Christian?!
The Church is called the "Body" of Christ often (e.g., Eph. 1:22-3), and is compared to a seed which grows into a tree (Mt. 13:31-2). Seeds and bodies grow and expand. Yet Protestants tend to see Church and Doctrine as more like a statue, subject to pigeon droppings (i.e., so-called Catholic "corruptions"!). This robs the metaphors of Christ of their essential meaning. It is impossible to claim that no development occurred in Church history, or that it ceased after the 1st, 2nd, 3rd, or 5th century, etc. (all arbitrary human traditions). The Bible is not absolutely clear in every part, and requires the developing wisdom of the Church.
Doctrines agreed upon by all develop, too. The Divinity or Godhood of Christ was only finalized in 325, and the full doctrine of the Trinity in 381.The dogma of the Two Natures of Christ (God and Man) was proclaimed in 451. These decisions of General Councils of the Church were in response to challenging heresies. Why should Protestants accept these authoritative verdicts, but reject similar proclamations on Church government, the Eucharist, Mary, Purgatory, etc.?
Although understanding increases, the essential elements of doctrines exist from the beginning. Today's Church shouldn't be expected to look like the primitive Church if it is a living, vibrant, spiritual organism. But even the early Church looks like a small "Catholic tree." It doesn't look like a Protestant "statue," doomed to be increasingly corrupted by an encroaching, "diabolical" Catholicism, as is imagined by millions of Protestants unacquainted with the early Church and the oldest source materials after the New Testament, such as the writings of St. Ignatius of Antioch (d.c. 110) and St. Clement of Rome (d.c.101).
John Henry Cardinal Newman (1801-1890), the great English convert to Catholicism, who is widely regarded as one of the most profound religious thinkers of his time, wrote in his Essay on the Development of Christian Doctrine (1845), the one indispensable work on this subject:
One thing at least is certain; whatever history teaches . . . at least the Christianity of history is not Protestantism. If ever there were a safe truth, it is this. And Protestantism . . . as a whole, feels it, and has felt it. This is shown in the determination . . . of dispensing with historical Christianity altogether, and of forming a Christianity from the Bible alone . . . To be deep in history is to cease to be a Protestant.The bulk of Newman's extraordinary work is devoted to the exposition of a series of analogies, showing conclusively that the Protestant static conception of the Church (both historically and theologically) is incoherent and false. He argues, for example, that notions of suffering, or "vague forms of the doctrine of Purgatory," were universally accepted, by and large, in the first four centuries of the Church, whereas, the same cannot be said for the doctrine of Original Sin, which is agreed upon by Protestants and Catholics.
(Introduction 5, 6)
Protestants falsely argue that Purgatory is a later corruption, but it was present early on and merely developed. Original Sin, however, was equally if not more so, subject to development. One cannot have it both ways. If Purgatory is unacceptable on grounds of its having undergone development, then Original Sin must be rejected with it. Contrariwise, if Original Sin is accepted notwithstanding its own development, then so must Purgatory be accepted.
Thus Protestantism is inconsistent in its selective espousal of Christian beliefs. The so-called "Catholic distinctives" were merely cast off at the time of the Protestant Revolt in the 16th century - basically due to prejudice and ignorance. Protestantism ever since has had to either distort, ignore, or be embarrassed by the facts of early Christian history which, again and again, are found to be much more in conjunction with Catholicism. Protestant anti-Catholic apologists are notorious for searching for quotes by Church Fathers which appear to support their presuppositions, while bypassing those (often by the same Father) which clearly suggest the Catholic outlook. I did this myself in the year before I was convinced of the truth of Catholicism.
Newman states, in summary:
If it be true that the principles of the later Church are the same as those of the earlier, then, whatever are the variations of belief between the two periods, the later in reality agrees more than it differs with the earlier, for principles are responsible for doctrines. Hence they who assert that the modern Roman system is the corruption of primitive theology are forced to discover some difference of principle between the one and the other; for instance, that the right of private judgment was secured to the early Church and has been lost to the later, or again, that the later Church rationalizes and the earlier went by faith.This is true whether the theological considerations are those agreed upon by all, such as the Divinity of Christ, the Two Natures of Christ, the Trinity, the Holy Spirit, Original Sin, and the Canon of Scripture, or those denied by Protestants, such as the Marian dogmas, Purgatory, the papacy, the Real Presence of Christ in the Eucharist, the Communion of Saints, priestly absolution, baptismal regeneration, the Sacrifice of the Mass, etc.
(Ibid., ch. 7, section 6: conclusion)
If anything must be described, then, as a corruption of primitive, pure Christianity, it is Protestantism, not Catholicism, since it introduced a radically new mode of Christian authority which was a 180-degree departure from the established Christian Tradition: that of subjective, private judgment, tied in with the unbiblical, unhistorical, and unreasonable notion of "Scripture Alone." Protestantism is much more of a corruption, if that word is defined as an essential change of direction or philosophy of an institution or a set of beliefs (in this case theological and spiritual).
One might say that an automobile was "corrupt" if the owner decided that it ran better with no muffler, no shocks, no air or fuel filters, half of its spark plugs, watered-down gas, no rear brakes, one headlight, no heat, three quarts low on oil, with half of its radiator coolant, etc. Corruption can consist of "subtraction" as well as "addition." Protestantism's charges against Catholicism, closely scrutinized, only come back to incriminate itself.
By and large, Protestantism merely asserts "sola Scriptura" without much consideration of the seriously-flawed implications of the same, and judges all doctrines accordingly. Therefore, those which are deemed to be either outright unbiblical or insufficiently grounded in Scripture to be authoritative, are jettisoned: the Marian doctrines, Purgatory, Penance, the papacy, etc. Apart from the question of Tradition as a legitimate carrier (alongside and in harmony with Scripture) of Christian belief, much more biblical support can be found in Scripture for these "Catholic" doctrines than Protestants suppose.
One simply needs to become familiar with Catholic biblical apologetic arguments. The idea of doctrinal development is a key, in any case, for understanding why the Catholic Church often appears on the surface as fundamentally different than the early Church. Thoughtful Protestants owe it to themselves and intellectual honesty to ponder this indispensable notion before lashing out at the allegedly "unbiblical excesses" of Catholicism.