Here's a quote from Karl Adam's The Spirit of Catholicism:
"We Catholics acknowledge readily, without any shame, nay with pride, that Catholicism cannot be identified simply and wholly with primitive Christianity, nor even with the Gospel of Christ, in the same way that the great oak cannot be identified with the tiny acorn. There is no mechanical identity, but an organic identity. And we go further and say that thousands of years hence Catholicism will probably be even richer, more luxuriant, more manifold in dogma, morals, law and worship than the Catholicism of the present day."
The question I have for my Roman Catholic readers, how do you know when a doctrine has fully developed?