Arrested Development?

One of the most interesting and challenging arguments used by Catholics to defend doctrines that Protestants consider pure novelties is the argument from the devel-opment of doctrine, which states that though the initial deposit of the faith was given intact to the apostles and from the apostles to the first generation of bishops, the church’s understanding of the deposit develops over time, usually as a result of controversy or heresy.

There are a couple examples that are commonly used by Catholics to demonstrate their point. One is the canon of Scripture. Though by the year 90 AD (or thereabouts) the final book of the New Testament had been written, it took the church a good number of years to arrive at this conclusion. Likewise with the doctrine of the Trinity or the hypostatic union of the two natures in the one Person of Christ. The fact that these doctrines were not formally propounded until the fourth- and fifth centuries does not in any way diminish their validity. Therefore, insists the Catholic, just because the dogmas of papal infallibility or the assumption of the blessed virgin Mary were not formulated until the nineteenth century does not mean we should balk at them. If the Trinity had taken another thousand years to state officially, would it be any less true?

Now on the one hand this makes a lot of sense. I mean, a case could certainly be made that the church of Acts 2 would barely have recognized the church of Acts 15 if it had been given a crystal ball. Elders? Deacons? Gentiles? What happened to our simple movement, how did it get so complex?

But on the other hand, I fail to see how certain dogmas can honestly be said to be developments in the church’s understanding of the original deposit of faith, and when I hear Catholics insist that they would never think of adding anything to what God has revealed in his Word, I just scratch my head. Take the sale of indulgences as one example (does that one count as dogma?), or take as another the immaculate conception and assumption of Mary. Sure, I’ve read the arguments and heard the logic behind these teachings, and though they are unpersuasive they are certainly plausible. But insisting that they are actually biblical, well, that’s another issue.

What am I missing?