So is John F. McCarthy pope?
Fr. McCarthy is not Pope. Rather, Fr. McCarthy attempts to show how Dignitatis Humane and Quanta Cura are not contradictory, that being one of the bedrock principles of the Catholic Magisterium - non-contradiction of papal teaching. In this sense, he is acting as a faithful theologian attempt to resolve the perplexing question you raise.
Remember, if we have two documents from the Popes A and B which appear to be contradictory, the misunderstanding is ALWAYS on our part in not comprehending the Papal teaching, not on the part of the Pope and his supposed misunderstanding of the intention and thoughts of his predeessors.
INSTRUCTION ON THE ECCLESIAL VOCATION OF THE THEOLOGIAN
THE MAGISTERIUM AND THEOLOGY
A. Collaborative Relations
21. The living Magisterium of the Church and theology, while having different gifts and functions, ultimately have the same goal: preserving the People of God in the truth which sets free and thereby making them "a light to the nations". This service to the ecclesial community brings the theologian and the Magisterium into a reciprocal relationship. The latter authentically teaches the doctrine of the Apostles. And, benefiting from the work of theologians, it refutes objections to and distortions of the faith and promotes, with the authority received from Jesus Christ, new and deeper comprehension, clarification, and application of revealed doctrine. Theology, for its part, gains, by way of reflection, an ever deeper understanding of the Word of God found in the Scripture and handed on faithfully by the Church's living Tradition under the guidance of the Magisterium. Theology strives to clarify the teaching of Revelation with regard to reason and gives it finally an organic and systematic form.(20)
22. Collaboration between the theologian and the Magisterium occurs in a special way when the theologian receives the canonical mission or the mandate to teach. In a certain sense, such collaboration becomes a participation in the work of the Magisterium, linked, as it then is, by a juridic bond. The theologian's code of conduct, which obviously has its origin in the service of the Word of God, is here reinforced by the commitment the theologian assumes in accepting his office, making the profession of faith, and taking the oath of fidelity.(21)
From this moment on, the theologian is officially charged with the task of presenting and illustrating the doctrine of the faith in its integrity and with full accuracy.
23. When the Magisterium of the Church makes an infallible pronouncement and solemnly declares that a teaching is found in Revelation, the assent called for is that of theological faith. This kind of adherence is to be given even to the teaching of the ordinary and universal Magisterium when it proposes for belief a teaching of faith as divinely revealed.
When the Magisterium proposes "in a definitive way" truths concerning faith and morals, which, even if not divinely revealed, are nevertheless strictly and intimately connected with Revelation, these must be firmly accepted and held.(22)
When the Magisterium, not intending to act "definitively", teaches a doctrine to aid a better understanding of Revelation and make explicit its contents, or to recall how some teaching is in conformity with the truths of faith, or finally to guard against ideas that are incompatible with these truths, the response called for is that of the religious submission of will and intellect.(23) This kind of response cannot be simply exterior or disciplinary but must be understood within the logic of faith and under the impulse of obedience to the faith.
24. Finally, in order to serve the People of God as well as possible, in particular, by warning them of dangerous opinions which could lead to error, the Magisterium can intervene in questions under discussion which involve, in addition to solid principles, certain contingent and conjectural elements. It often only becomes possible with the passage of time to distinguish between what is necessary and what is contingent.
The willingness to submit loyally to the teaching of the Magisterium on matters per se not irreformable must be the rule. It can happen, however, that a theologian may, according to the case, raise questions regarding the timeliness, the form, or even the contents of magisterial interventions. Here the theologian will need, first of all, to assess accurately the authoritativeness of the interventions which becomes clear from the nature of the documents, the insistence with which a teaching is repeated, and the very way in which it is expressed.
(24) When it comes to the question of interventions in the prudential order, it could happen that some Magisterial documents might not be free from all deficiencies. Bishops and their advisors have not always taken into immediate consideration every aspect or the entire complexity of a question. But it would be contrary to the truth, if, proceeding from some particular cases, one were to conclude that the Church's Magisterium can be habitually mistaken in its prudential judgments, or that it does not enjoy divine assistance in the integral exercise of its mission. In fact, the theologian, who cannot pursue his discipline well without a certain competence in history, is aware of the filtering which occurs with the passage of time. This is not to be understood in the sense of a relativization of the tenets of the faith. The theologian knows that some judgments of the Magisterium could be justified at the time in which they were made, because while the pronouncements contained true assertions and others which were not sure, both types were inextricably connected. Only time has permitted discernment and, after deeper study, the attainment of true doctrinal progress.
25. Even when collaboration takes place under the best conditions, the possibility cannot be excluded that tensions may arise between the theologian and the Magisterium. The meaning attributed to such tensions and the spirit with which they are faced are not matters of indifference. If tensions do not spring from hostile and contrary feelings, they can become a dynamic factor, a stimulus to both the Magisterium and theologians to fulfill their respective roles while practicing dialogue.
26. In the dialogue, a two-fold rule should prevail. When there is a question of the communion of faith, the principle of the "unity of truth" (unitas veritatis) applies. When it is a question of differences which do not jeopardize this communion, the "unity of charity" (unitas caritatis) should be safeguarded.
27. Even if the doctrine of the faith is not in question, the theologian will not present his own opinions or divergent hypotheses as though they were non-arguable conclusions. Respect for the truth as well as for the People of God requires this discretion (cf. Rom 14:1-15; 1 Cor 8; 10: 23-33 ) . For the same reasons, the theologian will refrain from giving untimely public expression to them.
28. The preceding considerations have a particular application to the case of the theologian who might have serious difficulties, for reasons which appear to him wellfounded, in accepting a non-irreformable magisterial teaching.
Such a disagreement could not be justified if it were based solely upon the fact that the validity of the given teaching is not evident or upon the opinion that the opposite position would be the more probable. Nor, furthermore, would the judgment of the subjective conscience of the theologian justify it because conscience does not constitute an autonomous and exclusive authority for deciding the truth of a doctrine.
29. In any case there should never be a diminishment of that fundamental openness loyally to accept the teaching of the Magisterium as is fitting for every believer by reason of the obedience of faith. The theologian will strive then to understand this teaching in its contents, arguments, and purposes. This will mean an intense and patient reflection on his part and a readiness, if need be, to revise his own opinions and examine the objections which his colleagues might offer him.
30. If, despite a loyal effort on the theologian's part, the difficulties persist, the theologian has the duty to make known to the Magisterial authorities the problems raised by the teaching in itself, in the arguments proposed to justify it, or even in the manner in which it is presented. He should do this in an evangelical spirit and with a profound desire to resolve the difficulties. His objections could then contribute to real progress and provide a stimulus to the Magisterium to propose the teaching of the Church in greater depth and with a clearer presentation of the arguments.
In cases like these, the theologian should avoid turning to the "mass media", but have recourse to the responsible authority, for it is not by seeking to exert the pressure of public opinion that one contributes to the clarification of doctrinal issues and renders service to the truth.