Code of Canon Law (25 January 1983):
St. Thomas Aquinas is mentioned twice in the 1983 Code, once by name and once by implication. Canon 252 § 3, regulating various aspects of seminary formation, states: “There are to be classes in dogmatic theology which are always to be based upon the written word of God along with sacred tradition, in which the students may learn to penetrate ever more profoundly the mysteries of salvation, with St. Thomas as their teacher in special way…”[43] The express reference to St. Thomas in the 1983 Code is new not only in the sense that the Pio-Benedictine Code made no such reference,[44] but also in that this explicit mention of St. Thomas was not made until the final draft of this canon.[45] Considering, however, that St. Thomas was expressly honoured by Vatican II for his theological teaching,[46] however, the appearance of the Angelic Doctor in the Code is not entirely surprising.
But while Canon 252 speaks of St. Thomas in his capacity as a teacher of theology, Canon 251 refers to him, though not by name, as a trustworthy teacher of philosophy as well. For practical purposes, Canon 251 had no predecessor in the Pio-Benedictine Code,[47] and instead it traces its roots to Conciliar teaching and post-conciliar documents.
Paragraph 15 of the Second Vatican Council’s Decree on the Training of Priests stated that seminary “students should rely on that philosophical patrimony which is forever valid….”[48] When asked just two months later what was to be the concrete understanding of the Council’s reference to a philosophical system “forever valid”, the Congregation for Seminaries and Universities replied Saint Thomas.[49] It repeated this identification of St. Thomas as the preeminent teacher of perennially valid philosophy in 1972.[50] Thus the revision commission, when queried why St. Thomas was not expressly named in what was to become Canon 251 of the new code, replied that there was no need to name St. Thomas in this context, for he is already indicated by the term “perennially valid philosophy.”[51] All modern commentaries on canon law recognize St. Thomas as the referent of Canon 251.[52]"
[46] See Second Vatican Council, Gravissimum educationis (Declaration on Christian Education) 28 October 1965, No. 10.
[49] See Sacred Congregation for Seminaries and Universities, “Private Reply”, 20 December 1965, reprinted in Canon Law Digest 6 (1963-1967) 252.
[50] See Sacred Congregation for Catholic Education, “Study of Philosophy in Seminaries”, 20 January 1972, reprinted in Canon Law Digest 9 (1978-1981) 807-821, esp. 820.
[52] [...] Saint Thomas is, by the way, the only saint mentioned in the 1983 Code who does not enjoy a preceptive holy day of obligation.
(cf Marian and cultic references in the 1983 Code of Canon Law, by Dr. Edward N. Peters, on http://www.canonlaw.info/a_mary.htm)
DECREE ON THE REFORM OF ECCLESIASTICAL STUDIES OF PHILOSOPHY (28 January 2011)
“IV. Philosophical Formation in Ecclesiastical Institutions of Higher Learning
10. [...] philosophical preparation is, in a particular way, a “crucial stage of intellectual formation” for future priests: “only a sound philosophy can help candidates for the priesthood to develop a reflective awareness of the fundamental relationship that exists between the human spirit and truth, that truth which is revealed to us fully in Jesus Christ.”[21] In fact, “the study of philosophy is fundamental and indispensable to the structure of theological studies and to the formation of candidates for the priesthood. It is not by chance that the curriculum of theological studies is preceded by a time of special study of philosophy.”[22]
11. Within Ecclesiastical academic institutions, a suitable philosophical formation must involve both intellectual “habitus” (plural) and contents.
With the acquisition of intellectual, scientific and sapiential “habitus”, reason learns to know more than empirical data. In a particular way, the intellectual debate in pluralistic societies, which are strongly threatened by relativism and ideologies, or in societies without authentic freedom, demands that the students in Ecclesiastical Faculties acquire a solid philosophical forma mentis. These “habitus” make it possible to think, know and reason with precision, and also to dialogue with everyone incisively and fearlessly.
The “habitus” are, though, connected with the assimilation of firmly acquired contents. In other words, they derive from the knowledge and deepening of the most important truths gained by philosophical labour, sometimes with the help of Divine Revelation. To arrive at a rigorous and coherent knowledge of man, the world and God,[23] the “habitus” require that the teaching of philosophy be rooted in “the eternally valid philosophical heritage”, developed over time, and, at the same time, be open to accepting the contributions that philosophical research has provided and continues to provide.[24] Among those fundamental truths, some are of central importance and are particularly relevant today: the capacity to reach objective and universal truth as well as valid metaphysical knowledge;[25] the unity of body and soul in man;[26] the dignity of the human person;[27] relations between nature and freedom;[28] the importance of natural law and of the “sources of morality,”[29] particularly of the object of the moral act;[30] and the necessary conformity of civil law to moral law.[31]
12. The philosophy of Saint Thomas Aquinas is important both for the acquisition of intellectual “habitus” and for the mature assimilation of the philosophical heritage. He knew how to place “faith in a positive relation with the dominant form of reason of his time.”[32] For this reason, he is stilled called the “apostle of truth.”[33] “Looking unreservedly to truth, Thomas’ realism was able to recognize the objectivity of truth and produce not merely a philosophy of ‘what seems to be’ but a philosophy of ‘what is’.”[34] The Church’s preference for his method and his doctrine is not exclusive, but “exemplary”.[35]”
[...]
Art. 59 [Aims of an Ecclesiastical Faculty of Philosophy]
§ 1. The research and teaching of philosophy in an Ecclesiastical Faculty of Philosophy must be rooted in the “philosophical patrimony which is perennially valid”,[42] which has developed throughout the history, with special attention being given to the work of Saint Thomas Aquinas. [...]
On the [feast] of St Thomas Aquinas, (28 January 2011)
Zenon Card. Grocholewski
Præfectus
Ioannes Ludovicus Bruguès, O.P.
a Secretis”
Excerpt from the Constitutions of the FSSP (definitevely approved by the Holy See on 29 July 2003):
"10. [...] The philosophical and theological studies in the seminary will be founded on the principles and the method of Saint Thomas Aquinas, and will thus be conformed to the desires and prescriptions so often renewed by popes, councils, and the Code of Canon Law. Thus the seminarians will carefully avoid modern errors as much in philosophy as in theology. (See Pius X, Pascendi, AAS 40 (1907), 596 ff.; Pius XII, Humani generis, AAS 42 (1950), 561 ff; Paul VI, Mysterium fidei, AAS 57 (1965), 753 ff.).
11. In the Fraternity, the formation of priests will be conformed to the dispositions of the ratio studiorum promulgated by the Holy See. A directory specifies the curriculum at the seminary, in conformity with the law."