A pronouncement cannot be ex cathedra if it conflicts with previously established infallible teaching. An infallible teaching, by its nature, can never be overturned.
The Infallibility of the pope is a figment of vain imaginations made up out of whole cloth.
Catholic theologian Hans Küng, critical of this dogma, argues for four principle reasons: "Pius IX had a sense of divine mission which he carried to extremes; he engaged in double dealing; he was mentally disturbed; and he misused his office."
Pius may have been insane. He suffered from seizures his entire life and later developed memory loss and an inability to think clearly for long periods of time (by his own admission). By 1869, disease and stress had taken a serious toll on his psychological state and people noticed that he had become unpredictable, irrational, emotional and dictatorial — sometimes acting like a megalomaniac. Historian Ferdinand Gregorovius reported that 1870:
The pope recently got the urge to try out his infallibility...While out on a walk he called to a paralytic: "Get up and walk." The poor devil gave it a try and collapsed, which put [the pope] very much out of sorts. The anecdote has already been mentioned in newspapers. I really believe he's insane.
Pius may have been dishonest. Pius stacked the council heavily in his favor. Cardinal Gustav von Hohenlohe told a friend: "In my entire life, I have never met a man who was less particular about the truth than Pius IX." Other bishops, like Bishop Henir Manret, openly called Pius IX a liar, so the charge was not at all unusual.
Upon later reflection, many of the inexperienced members came to believe that their ill-fated appointments occurred only so that they could more easily be outmaneuvered by the pope's supporters. One, Bishop Joseph Karl Hefele wrote to a friend:
"The longer I stay here, the more clearly I see the duplicity behind my appointment as consultor concilii. That was just Rome's way of hoodwinking the public with the appearance of neutrality. In reality, I have no idea what I'm supposed to be doing here."
Who originally came up with the idea of papal infallibility? It was the creation of Peter Olivi, a Franciscan who was more than once accused of heresy (an auspicious parent for the concept of infallibility, wouldn't you say?). His reason for attempting to limit papal power seems to have been to prevent future popes from rescinding a ruling favorable to Franciscans made by Pope Nicholas III (1277-1280). Nicholas was willing to go along with this idea, but later popes rejected it outright. For example, Pope John XXII (1316-1334) went so far as to call it "...a work of the devil...the Father of Lies." and in 1324 actually issued a papal bull condemning it as heresy.
http://www.oldcatholichistory.org/wiki/papal_infallibility_part_2
Hans Küng is infamous as a strark raving liberal. He has been censured by the Church.
Pius may have been insane.
LOL. Not nearly as insane as many modern liberal theologians. Pius IX was under the stress of fighting a civil war against the Italian Free Masons and had to flee for his life from Rome on occasion. Still, his writings are rational and straightforward, unlike the writings of Hans Küng.
Who originally came up with the idea of papal infallibility? It was the creation of Peter Olivi, a Franciscan who was more than once accused of heresy
The Church has always acted upon the assumption of infallibility. St. Irenus, disciple of St. Polycarp who was successor to John, defended Church infallibility and the primacy of Rome in his work "Against Heresies."
http://www.oldcatholichistory.org/wiki/papal_infallibility_part_2
The "Old Catholics" are now ordaining women and open homosexuals.