Rev. Gregory Hesse (1953-2006) held a doctorate in both Canon Law and Theology. I have been listening to various lectures of his on various topics, including canon law, the papacy, and tradition. Apart from having a near photographic memory of Denzinger's The Sources of Catholic Dogma and other important sources, Hesse also had a lot of intellectual integrity. In the following presentation, he discusses the many instances of papal fallibility and error from a Roman Catholic perspective of doctrines and morals (be sure to share this with a Roman apologist who claims that the pope has never erred on issues of morals and/or dogma and/or that having a pope ensures there will never be theological disputes and confusion):
Fallibility Of The Popes Fr Hesse
If one is interested in pursuing such issues in more detail, see:
Bibliography on the Papacy and Papal Infallibility
Fallibility Of The Popes Fr Hesse
If one is interested in pursuing such issues in more detail, see:
Bibliography on the Papacy and Papal Infallibility