The Pope’s own words in Ordinatio Sacerdotalis: definitive tenendum, mean precisely “requiring to be held definitively.”
Closely following Bishop Gasser’s explanation, Vatican II shows that it considers the words “define” and “proclaim” to be equivalent by using the word “definition” when it states: “Therefore his definitions are rightly called irreformable, etc.” Lumen Gentium, 25].
Fr Brain Harrison, O.S.:
“In the final analysis, therefore, the reason the Church has always rejected female service in the sanctuary is that such service is very closely related, both symbolically and often causally, to the ministerial priesthood itself. And this can never possibly be conferred upon women, as John Paul II declared on the Feast of Pentecost last year in what is clearly an infallible,* ex cathedra *definition. 10
“10. It stops short, however, of being a solemn dogmatic definition on a par with those of the Immaculate Conception and Assumption, which are defined as truths of faith, binding on pain of heresy. Cf. the present writer’s article, “Cardinal Ratzinger on Ordinatio Sacerdotalis,” The Priest (Journal of the Australian Confraternity of Catholic Clergy), Spring 1994 / Summer 1995, pp. 5-6.”
On Ordinatio Sacerdotalis
Congregation for the Doctrine of the Faith
October 28, 1995
“Dubium: Whether the teaching that the Church has no authority whatsoever to confer priestly ordination on women, which is presented in the Apostolic Letter [Epistle] *Ordinatio Sacerdotalis *to be held definitively, is to be understood as belonging to the deposit of faith.
Responsum: In the affirmative.
“This teaching requires definitive assent, since, founded on the written Word of God, and from the beginning constantly preserved and applied in the Tradition of the Church, it has been set forth infallibly by the ordinary and universal Magisterium (cf. Second Vatican Council, Dogmatic Constitution on the Church Lumen Gentium] 25, 2). Thus, in the present circumstances, the Roman Pontiff, exercising his proper office of confirming the brethren (cf. Lk 22:32), has handed on this same teaching by a formal declaration, explicitly stating what is to be held always, everywhere, and by all, as belonging to the deposit of the faith.”
Joseph Card. Ratzinger
The meaning of the word ‘define’ was explained to the Fathers of Vatican I, before they promulgated the dogma of papal infallibility, as follows: “the pope is said to ‘define’ a doctrine when he passes judgment directly and finally, ‘in such a way that each and every Catholic can be certain as to the mind of the Apostolic See and of the Roman Pontiff.’ ”
Answer by David Gregson of EWTN on Nov-22-2002:
“You are correct in stating that the Pope exercises his charism of infallibility not only in dogmatic definitions issued, ex cathedra, as divinely revealed (of which there have been only two), but also in doctrines definitively proposed by him, also ex cathedra, which would include canonizations (that they are in fact Saints, enjoying the Beatific Vision in heaven), moral teachings (such as contained in Humanae vitae), and other doctrines he has taught as necessarily connected with truths divinely revealed, such as that priestly ordination is reserved to men. Further details on levels of certainty with which the teachings of the Magisterium (either the Pope alone, or in company with his Bishops) may be found in Summary of Categories of Belief.”
The three levels of teaching from *Ad Tuendam Fidem *are:
1) Dogma – infallible (Canon #750.1) to be believed with the assent of divine and Catholic faith.
2) Doctrine – infallible (Canon #750.2) requires the assent of ecclesial faith, to be “firmly embraced and held”.
3) Doctrine – non-definitive (non-infallible) and requires intellectual assent (“loyal submission of the will and intellect”, Vatican II, *Lumen Gentium 25), not an assent of faith. See the Explanatory Note on ATF by the Congregation for the Doctrine of the Faith at ewtn.com/library/CURIA/CDFADTU.HTM