Now that is interesting, Ladislaus, and I would be interested to learn more about the meaning of the Pope acting as a PRIVATE PERSON. The impression I get is that this is often used by theologians to mean whenever the Pope is not invoking his supreme authority as the infallible teacher of the Church, that is, speaking ex cathedra. You oppose the term, however, to the Pope acting "officially". Can you substantiate that?
Well, in more recent times we have a very clear rule of thumb. If something appears in the
Acta Apostolicae Sedis, it's the intention of the Pope to act as Pope. These aren't the
Acta Jorge Bergoliensis, but Acts of the See itself. Essentially it depends on the intention of the Pope to be acting in his capacity as Pope, vs., in this case, as Jorge Bergoglio. In the past, there was some debate about inferring that intention, often due to the nature of a docuмent (Bull, Encyclical, etc.), but with the creation of AAS, any ambiguity is cleared up.
Simply because the Pope is teaching non-infallibly, say, in an Encyclical letter, does not translate to him acting as a "Private Person". He's clearly acting in his official capacity as Pope.
That's actually all that the term
ex cathedra actually means. This term has been turned into a shorthand for when the Pope is acting infallibly, but that's not technically correct. Acting
ex cathedra is simply ONE of the notes of infallibility.
Here's from
Pastor Aeternus:
Therefore, faithfully adhering to the tradition received from the beginning of the christian faith, to the glory of God our savior, for the exaltation of the Catholic religion and for the salvation of the christian people, with the approval of the Sacred Council, we teach and define as a divinely revealed dogma that when the Roman Pontiff speaks EX CATHEDRA, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals. Therefore, such definitions of the Roman Pontiff are of themselves, and not by the consent of the Church, irreformable.
That parenthetical "that is" actually defines the term
Ex Cathedra, and private person is the opposite of
Ex Cathedra, namely when he's NOT exercising his office as shepherd and teacher of all nations. So even in a simple non-infallible Encyclical letter, he's still exercising his office as shepherd and teacher of all Christians, but not necessarily defining a doctrine of faith and morals ... etc. etc.
In the past, things where the Pope might be writing a letter to an individual bishop, or giving a sermon, or opining privately (such as when Jorge is answering questions on his plane), those are acts generally construed as the Pope acting as a private theologian, since they're not addressed authoritatively to all Christians. But, as I said, in recent days, the inclusion of something in AAS has served to remove all ambiguity and guessing regarding his intentions.