the inerrancy doctrine should be decreed: because this truth has been denied; because, if not decreed, the error will henceforward appear to be tolerated, or at least left in impunity; because this denial of what Manning called "the traditional belief of the Church" was an organised opposition to the prerogatives of the Holy See; "because it is needed to place the Pontifical Acts of the last 300 years, both in declaring the truth, as in the dogma of the Immaculate Conception, and in condemning errors, as in the long series of propositions condemned in … Jansen and others, beyond cavil or question"; because it was openly said that the pastors of the Church are not unanimous, therefore "it is of the highest moment to expose and extinguish this false allegation, so boldly and invidiously made by heretics and schismatics of every name."
The dogma was necessary also to justify the believer's attitude toward the Pope. Faith, argued Manning, requires the Infallibility of the teacher of truth. If the teacher be fallible, our certainty cannot be Divine. If the Pope be fallible, we cannot be certain that the doctrines propounded by him—the Immaculate Conception, for instance—are of faith. "The treatise of Divine Faith is therefore incomplete so long as the Infallibility of the proponent is not fully defined."
Thus a theoretical system requires completion which nothing but this dogma can give ; for which, therefore, this dogma must be created. Moreover, Manning scorns what he calls "the incoherence of admitting a supremacy and denying its infallible action." We have here a reminiscence of De Maistre. There is the same theorising tendency. Two dominant ideas are found throughout. The one, that the doctrine is required to secure the completion of an à priori view.
