There are implications to this thread in other areas, and all relate to a critical definition of terms, which as Aristotle and St. Thomas I think agree is a necessary beginning before there can be any reliable discourse.
We see this all over the place: what is "necessity" when it comes to the sacrament of baptism, or when it comes to the Church and salvation; what does the "infallibility" or "indefectibility" of the Church mean, and when is the Magisterium infallible or indefectible (if it is)? My own view is that the thought and definitions of the theologians, and even the teaching Church (at least most definitely in instances below the level of the universal, ordinary Magisterium certainly, even in the "authentic" Magisterium - witness Pope Francis) created problems in this regard that lead to and inspired the errors of Vatican II.
As far as I can see,
Indefectibility of the Church and
Infallibility of the Church are concepts of theologians and not teachings of the Magisterium proposed to be believed by the faithful. Each theologian gives his own definition of these/such terms and then quotes the Magisterium, Fathers, etc. to convince his readers. There are related propositions we have to believe, but it's not easy to find them all.
E.g. Ludwig Ott:
Die Kirche ist indefektibel, d.h. sie bleibt bis zum Ende der Welt als die von Christus gestiftete Heilsanstalt bestehen. (
The Church is indefectible, i.e. she shall persist until to the end of the world as the salvific institution founded by Christ.) Then he qualifies this as
Sententia certa. This "definition" is then wrapped into a lot of text stating various seemingly related propositions, garnished with quotes of Councils, Popes, Fathers etc.
Theology is not mathematics, and even in mathematics many terms include the name of a mathematician to make sure the reader knows how the term is defined. Let's speak about
Hilbert space or
Ott indefectibility.
Now, Ott doesn't even care to mention what "until to the end of the world" exactly means. His first quote is taken from the Vatican Council, but he neither quotes the first paragraph of
Dei filius nor of
Pastor aeternus. Later on though, he does quote Mt 28:20 (
consummation of the age translated to German as
Ende der Welt).
Dei Filius et generis humani Redemptor Dominus Noster Iesus Christus, ad Patrem caelestem rediturus, cuм Ecclesia sua in terris militante, omnibus diebus usque ad consummationem saeculi futurum se esse promisit.
The Son of God, redeemer of the human race, Our Lord Jesus Christ, when about to return to his heavenly Father, promised that he would be with his church militant upon earth all days even to the future consummation of the age.
Pastor aeternus [...] ita in Ecclesia sua Pastores et Doctores usque ad consummationem saeculi esse voluit.
The eternal shepherd [...] in like manner it was his will that in his church there should be shepherds and teachers until the consummation of the age.
By quoting Mt 28:20,
until the consummation of the age, the Vatican Council redirects the readers to scripture and the exegesis of the Fathers. Anyone praying the Divine Office (at the time of the Vatican Council), read the exegesis of St. Jerome on Matthew 24:15-35 once a year on the last Sunday after Pentecost; Jerome equates the consummation of the age and the abomination of desolation and the reign of Antichrist.
There must be a reason, why theologians of more recent times seem unaware of the subtleties of the term
consummation of the age used right at the beginning of
Dei Filius and
Pastor aeternus. I can only guess: The Apostle Paul speaks about an
operation of error sent by God to lead many to the slaughterhouse of Antichrist. CI user
Incredulous has it in his signature:
in those days Our Lord Jesus Christ will send them not a true Pastor but a destroyer ("deathbed warning of St. Francis of Assisi"). Some of the Old Testament prophets announce that God will send a
pastor stultus, a foolhardy shepherd, who will slaughter and sell the flock. Or alternatively (for vegans) at harvest time the fields are burnt down, the vines and olive trees are cut down. The bad shepherd or grower is identified as Antichrist by the Fathers. God's
sword is inebriated in heaven (apostate bishops of the Church)
it shall come down upon the people of my slaughter unto judgment (Is 34:5). If God sends the
operation of error to ensure that those sheep
who have not believed the truth, but have consented to iniquity don't flee from Juda, it may be convenient that the manuals of theologians do not tell all the details about the consummation of the age. But as I said, that's just a guess.