Question.—What is the Catholic argument for Papal infallibility ? (S.W.)
Answer.—We have already seen that Christ established a divine, infallible authority to teach His gospel until the end of the world, just as He taught it.
Once this is admitted it follows logically that the Supreme Head of this infallible Church must needs be infallible. For if St. Peter or his successor, speaking authoritatively to the Church, could teach false doctrine, then he would instantly cease to be the firm rockfoundation on which Christ built His Church, the gates of hell would prevail, error would be sanctioned by God in heaven (Matt, xvi 18, 19), the prayer of Christ for Peter personally would be fruitless, for the faith of the brethren would not be strengthened (Luke xxii 32), and the whole flock of Christ would be deprived of the true food of divine faith (John xxi 15-17).
Does it not seem probable that if in any organised state the framers of the administration were wise enough to establish a Supreme Court to settle practically and finally all disputes regarding the Constitution, in the Church the All-Wise Son of God, foreseeing and prophesying that false teachers would arise ("For there will arise false Christs and false prophets," (Mark xiii 22) would have provided a Supreme Court to infallibly (else no man is bound to believe) decide every controversy about written or unwritten doctrine? What has the Protestant denial of one Pope brought about save the creating of many, and an anarchy of opinion destructive among millions of all supernatural religion whatsoever?
(Lyons, Christianity and infallibility : Schanz, A Christian Apology, vol. iii., Ch.xiv.).