17 Many are captivated by the great show of erudition which is held out before them, and by the apparently convincing force of the proofs adduced, so that they either lose the faith or feel that it is greatly shaken in them. There are many too, firm in the faith, who accuse critical science of being destructive, while in itself it is innocent and a sure element of investigation when rightly applied. Both the former and the latter fail to see that they start from a false hypothesis, that is to say, from science falsely so called, which logically forces them to conclusions equally false. For given a false philosophical principle everything deduced from it is vitiated. But these errors will never be effectively refuted, unless by bringing about a change of front, that is to say, unless those in error be forced to leave the field of criticism in which they consider themselves firmly entrenched for the legitimate field of philosophy through the abandonment of which they have fallen into their errors.
Source: Iucunda Sane (Vatican.va)