From Hilaire Belloc's Survivals and New Arrivals:
The good fortunes of stupidity are incalculable. One can never tell what sudden resurrections ignorance and fatuity may not have.
Belloc's book is about heresy, and the "survivals" in the title are the heresies that seem to come back again and again, despite having been roundly refuted in the past. That phenomenon is one that our Church ought to take more note of, and plan to fight a whole lot better than we have been lately.
For instance, the apparently sudden popularity of a new Gnosticism (given a big glossy expression in The DaVinci Code) took the Church by surprise. It shouldn't have. Gnosticism comes back periodically throughout history. So why are we constantly behind the curve? Why are we always reacting at molasses-in-January speed? Why are our scholars not anticipating the likely errors that contemporary thought might fall into, and bringing the truth to bear quickly to head off the return of yet another "survival"?
I've often come back to the theme of the crucial importance of time. We don't have forever to stand up against evil and error, and failing to strike at it when it's new and weak means that later you have to stand against it -- if at all -- when it's established and powerful, and has already destroyed many souls.
So to the Vatican, and to our Catholic scholars everywhere, and to all us lay folks on whom so much now depends, I'd say: work carefully, by all means -- but work quickly. And let's not let ourselves be surprised, ever again.