Here is an excerpt:
When the pope speaks about matters of faith and morals, then, the question is not whether he uses a specific formula but whether it is sufficiently clear that he intends (1) by virtue of his supreme authority (2) to explain a doctrine (3) on a matter of faith or morals (4) to be held by the whole Church.
With the current scandals in the European Church, I have heard, from not a few people, the term papal infallibility tossed around with regard to Pope Benedict XVI's alleged involvement in specific investigation in Bavaria. First of all, as Archbishop Ratzinger, he was not protected by papal infallibility; secondly, papal infallibility is not retroactive; thirdly, the workings of the hierarchy of the Church are sorely misunderstood or completely foreign to most people, Catholics included.
There is a section in the Catechism of the Catholic Church on the hierarchy, but I would also recommend reading the Second Vatican Council documents, Lumen Gentium, Christus Dominus, Gaudium et spes, and Presbyterorum ordinis. Once one understands what the Church's hierarchy contains and how it is meant to operate, I would further recommend reading the section under the Catechism of the Catholic Church regarding the lay faithful and their responsibilities in the hierarchy. This can be found under the same section linked above. The Second Vatican Council also wrote a specific decree for the laity called, Apostolicam actuositatem, which is located at the link for the Vatican documents.
I've just thrown a huge amount of reading out there, but a properly educated Catholic is a necessity when it comes to defending and explaining doctrine. (I believe that press has made us acutely aware of that fact here in the US with regard to political leaders who profess to be practicing Catholics, yet flagrantly, and publicly, disregard Church teaching. They either don't understand it, or choose to ignore it.) This makes it imperative that when a term like Papal Infallibility is tossed around by the media, or by people in general, we not only need to understand what it means, but be able to explain how it operates in the papacy.
Dr. Mirus gives a clear and concise, as is possible, explanation of the function of Papal Infallibility and how to determine if it is in operation in the written or spoken words of our pontiff. I highly recommend reading his piece and then peruse the documents that I have suggested above. Anyone will be better able to respond to those who wishes to challenge the doctrine of infallibility of the pope on matters of faith and morals.
This may lead to a series summarizing these various documents -- let me know if you would appreciate hearing more about this.
God bless you!