Applied to our European culture, this means: if reason wishes to self-construct itself circumscribed by its own argumentation and that which convinces it for the moment, and - preoccupied with its secularity - cuts itself off from the roots through which it lives, then it does not become more reasonable and pure, but will decompose and break up
The faculty threatened the Pope, because he doesn’t follow their atheistic dogma, while BXVI talked of how faith and reason intertwine, and that true faith is freely given and accepted.