On the Catholic Priesthood
Infallibility of the Pope
Some seem to think that the claim of infallibility for the Pope means that the Pope is never wrong and can never err as other people do. Every Pope is a free man, personally responsible for his own salvation, personally capable of obeying or transgressing the law of God. Christ has endowed the Popes with infallibility only in the teaching of Christ's doctrine, not in their personal lives.
So You May Know the Truth
Protection from error is received by the successors of Saint Peter, not for their own personal advantage but for the advantage of the Church. They are protected from error in teaching so that the followers of Christ will be protected from error in believing.
It is given for the sake of the whole Church, in order that members of the Church throughout the world may always be preserved in the truth. It has nothing to do with the Pope's opinions or habits as an individual.
It does not mean that the Pope is incapable of human weaknesses or shortcomings. Nor does it have anything to do with science, the state of the nation or the best way to build a house.
The Pope has no authority to invent new doctrine. He has no more authority to break a divine law or to distort a single word of Scripture than anyone else. His function is to hand down unchanged the divine truth revealed by God to all generations of men. In this alone is he infallible, as promised by Christ.