Doctrinal "pluralism" in the early Church?

There is a common assumption among moderately-well educated people with at least a smattering of exposure to modern biblical scholarship that no "single Gospel" is to be found in the early Church, but rather a "pluralism" of rival Gospels. They point to the fact that early Christianity emerged from a predominantly Jewish environment where the first Christians continued to observe precepts of the Torah and only later evolved into a Gospel for the Gentiles that did not require them to submit also to the Jewish requirements such as circumcision. They extrapolate from this, sometimes under the distant influence of Hegel, to suggest that Christianity is ultimately a product of a synthesis between the early Hebraic outlook of Jesus and the Jesuralem party of Apostles and the later Hellenic outlook of Paul, the missionary to the Greek or Gentile world. Further, they take this as a justification for an ever evolving, changing conception of the Gospel that could allow for endless revisionism, even accommodating women priests, practicing homosexual bishops, and a univeralist gospel according to which everbody in the world is saved (even though the meaning of "salvation" has to be radically re-thought since, of course, there is really no Hell according to these folks).

Without going into the complexities of this misguided thesis that is the legacy of classic liberal Protestantism, a few simple observations may be in order. If the NT Church was so "pluralistic," why did St. John anathematize the Gnostics revisionists (who denied the Incarnation) as "antichrists"? Why did St. Paul submit his teaching for review by the Jerusalem authorities under the headship of St. Peter (Gal. 2:1-2; cf. 1:18-24) even though Paul was the extremely well-educated protege of the Rabbi Gamaliel while Peter was a mere fisherman? Why did Paul himself anathematize the Judaizers as partisans of "another Gospel" in such harsh language (cf. the opening chapter of Galatians)? ... Etc., etc., etc. The Church has never been "pluralistic" in the sense of formally allowing (let alone teaching) rival, conflicting doctrines. It is one thing to accept the Venerable Cardinal Newman's thesis that Christian doctrine has developed, as an Oak tree is the product of the organic development from a tiny Acorn. It is altogether another thing to suggest that the Church can evolve doctrines that contradict the Apostolic Deposit of Faith. There is nothing in Paul's religion that contradicts the teaching of Jesus and the Apostles, since Jesus never intended for His Gospel to be limited to Jews, even though it took time for His Jewish disciples to comprehend this fact. But the notion that Christianity could be "revised" to accommodate contemporary versions of Gnosticism, universalism, New Age ideas, "same sex marriages," and so forth, is so far fetched as to make one laugh, were it not such a egregiously serious matter that involved the de-naturing or evisceration of the Gospel. The Apostle John would surely call partisans of such nonsense "antichrists." St. Paul would surely denounce them as partisans of "another Gospel." Let us try to be charitable about this, without being naive and gullible.

A good antedote to the liberal protestant thesis about Paul's religion being something other than the religion of Jesus, Peter and the other apostles is the classic refutation of this nonsense by the venerable old Princeton Professor, J. Gresham Machen, The Origin of Paul's Religion (James Sprunt Lectures). Another related classic by the same author, probably one of the ten most important books I have ever read, is his memorable volume, Christianity and Liberalism.