No one is infallible except God.
Hans Küng, in Infallible?
One of the important obstacles to the ecumenical movement is the Roman Catholic dogma that the Pope, when speaking ex cathedra ("from the chair" of St. Peter) on matters of faith and morals, is infallible. Actually, the doctrine has only been invoked once since it was officially defined in 1870. That was when Pius XII declared in 1950 that Mary was assumed bodily into heaven. Last week, however, the Vatican issued a sharp warning that the doctrine stands as proclaimed. It came...