It is strange to hear such an argument from individuals who believe that every human being, learned and unlearned alike, is infallible through the principle of private judgment i.e., that one man's judgment is as good as another, and that everybody's judgment is correct.

Infallibility means that God guarantees that in matters of faith and morals the Pope cannot make a mistake.

Infallibility DOES NOT mean that the Pope cannot sin; nor does it mean that he cannot make a mistake in other matters such as history, politics, science and the like. Only when he declares a certain truth to be a matter of revelation is he infallible.

There are four conditions which are necessary in order that the Pope be infallible:

1. He must speak as the chief pastor and teacher of the Church. The words he uses must make it clear to all that he is speaking as the head of the Church in a matter of faith or morals.
2. He must be speaking to the universal Church, that is, to Christians everywhere in the world.
3. He must speak "ex cathedra," that is, officially, with supreme apostolic authority.
4. It must be on a matter of faith or morals, and not on any other subject. Proof for this is found in St. Paul's first Epistle to Timothy where he speaks of the Church of Christ as "the pillar and mainstay of truth." Likewise, in St. John's Gospel, "I will ask the Father and He will give you another advocate, to dwell with you forever."

This does not limit discussion or debate among its members, because the Church uses this protection of the Holy Ghost only in extreme cases where it is necessary to settle the truth of a question; and this, always on fundamental truths.