“So you determine what is and is not infallible based on what your Church tells you.”

Basically, but I need to explain this concept to you. To us the Church IS Christ in space and time. Christ is truly man and truly God. As God He is the source of all goodness, knowledge, truth, and therefore when I, as a Catholic Christian, allow the Church to guide me in the turbulent waters of this world, I am acknowledging that I don’t know it all, even if I have a very high I.Q. I’m trying to practice the virtue of humility by allowing the Church I claim to belong to, to guide me in this world. Another person may choose to have the secular society around him or her guide them, but they are taking a chance they will be confused because the world around us sends us conflicting and confusing messages all the time. I know there are people who think, “I think what I think and no one influences me.” I believe those folks are delusional at best. All of us are somehow influenced by the culture around us. I choose to be influenced by a Church claiming to be infallible in certain things, so I can trust it.

“like a child who does what they are told to do for fear they’ll be punished.”

It’s not a matter of being punished, it’s a matter of knowing one is doing the right thing in spite of living in a very confused world. There are two dimensions here I need to explain to you. If you grab the hand of a child to cross the street, that child is trusting you will safely cross the street without allowing anyone to hurt him or her. As believers we do have that type of trust in God.

The use of reason is equally important. Many accuse us of not using “reason” but I don’t know of any other Christian body that emphasizes the use of reason more than the Catholic Church. All you have to do is read the writings of St. Anselm, St. Albert the Great, St. Thomas Aquinas, St. Augustine and many of the Fathers of the Church to see how they use “reason” to understand their faith. Even in our own day you’ll find the encyclical Fide et Ratio, Faith and Reason, written by Blessed John Paul II which clearly states there is no conflict between reason and faith, so this idea that many have that Catholics do not use their reason in accepting the faith is simply not accurate. One thing is for sure, if a person thinks he already knows it all, the Church has nothing to offer him or her till he or she acknowledges a) we don’t know it all. b) The Church is not just and institution, this is the Mystical Body of Christ guiding me through this life. When we pray the Rosary we refer to this life as a “a valley of tears” meaning that what we must confront in this life ain’t pretty, but we are also a people of hope who rely in our Church for guidance in the midst of darkness. If not, then there is no point in belonging to a Church we believe is one among many.

But I thought you were an atheist. If so, how do you know the teachings of the Church?
As far as the “rock” reference is concerned, what I meant to say is that just as the sun is in no way affected by a human being crawling under a rock and refusing the warmth of the sun, the Church is in no way affected because there are Catholics who openly disobey her teachings. They are the one affected negatively, not the Church.

“You however, refuse to believe that’s possible.”
Correct, if indeed the Holy Spirit, the Third Person of the Blessed Trinity guides the Church, then error is impossible in her teachings, but to understand this reality, one needs to be a man or woman or faith. I frankly do not believe most people understand this truth because the distractions of the world are more important to them than listening to Christ’s Church.

No, the Church is not infallible in everything. The Pope can tell all U.S. Catholics tomorrow the winning numbers of the lottery and it would be foolish for us to listen to that advice because he might be wrong. The gift of infallibility does not cover such adventures in predectability.

“how do you determine when it is and when it isn’t infallible?”
The Church proclaims a body of teaching to either be infallible or not. Sometimes the teaching is part of the ordinary teaching of the Church and the Popes are adamant in telling us that is the teaching of the Church, like the non-ordination of women to the priesthood.
Christ is truly Man and truly God, we believe in the Blessed Trinity, the Scriptures are God’s word, the Blessed Virgin is immaculately conceived, etc. Those, we Catholics would call “infallible” teachings. I must contribute financially to my parish is a precpt of the Church that does not fall under infallibility. We must pray the Rosary is a beautiful devotion but hardly infallible.
Remember Marvin, we live in a secular society and a secular society where democracy and pluralism are alive and well, and such a society has a hard time understanding a hierarchical Church where the truth is objective and relativism is not welcome. When you and I engaged is these discussions, it’s almost like a Martian is talking to a creature from Venus. Unless we find a common language to communicate, it is almost impossible for us to understand one another, but I am glad to have the opportunity to write to you. It’s the teacher in me. I’ve been teaching for almost thirty years, so, at times, I’m going to sound pompous to you and others.