fallible without its head. But the head is always infallible by himself. Thus far the definition is express, and the infallibility of the Vicar of Christ is declared to be the privilegium Petri, a charisma attached to the primacy, a Divine assistance given as a prerogative of the Head. There is, therefore, a special fitness in the word pollere in respect to the Head of the Church. This Divine assistance is his special prerogative depending on God alone; independent of the Church, which in dependence on him is endowed with the same infallibility. If the definition does not decide that the Church derives its infallibility from the Head, it does decide that the Head does not derive his infallibility from the Church; for it affirms this Divine assistance to be derived from the promise to Peter and in Peter to his successors.
VI. Lastly, the definition fixes the dogmatic value of these Pontifical acts ex cathedra, by declaring that they are 'ex sese, non autem ex consensu Ecclesiæ, irreformabilia,' that is, irreformable in and of themselves, and not because the Church or any part or any members of the Church should assent to them. These words, with extreme precision, do two things. First, they ascribe to the Pontifical acts ex cathedra, in faith or morals an intrinsic infallibility; and secondly, they exclude from them all influx of any other cause of such intrinsic infallibility. It is ascribed alone to the Divine assistance given to the Head of the Church for that end and effect.
I need not add, that by these words many forms of error are excluded: as, first, the theory that the joint
