St. Thomas Aquinas
The studies in philosophy and theology follow the teaching of St. Thomas Aquinas, who is called the Common Doctor of the Church, because, according to Leo XIII, St. Pius X and Pius XI: “having studied the Fathers of the Church extensively, he inherited so to speak the understanding of them all, and he refuted in advance all future errors.”
The "Summa Theologica"
Archbishop Lefebvre, following the guidelines of St. Pius X,1 wanted the Summa Theologica of the Angelic Doctor, read in Latin, to be the manual of the seminarians:
The Summa could be summarized in this way: Coming from God in order to return to God by means of God. This is the destiny of mankind. What a marvel! What a program! The elaboration of this program in the school of St. Thomas Aquinas continually amazes us as we contemplate the mysteries of God’s wisdom, knowledge and charity and His mercy for His human creatures.2
The spiritual aspect of the "Summa"
The Summa has everything: dogmatic, moral, mystical theology, and since then it has had no equal. All the manuals are inspired by St. Thomas, but they lack the spirit, the Holy Ghost that breathes in the works of St. Thomas. Even so, St. Thomas makes for rather dry reading, and yet there are often one or two well-wrought sentences that sum up the spiritual aspect of the doctrine being taught and open up to you extraordinary vistas.3
“Make your synthesis”: Jesus Christ
Here is the singular instruction given by the founder to his seminarians: “Make your synthesis!” This explains the regulation for the seminaries of the Society concerning studies:
The seminarians will increase their faith and their knowledge of Our Lord Jesus Christ and of His work of redemption by a meditative study of the natural and supernatural facts taught by philosophy, theology, Sacred Scripture, Church history, and Canon Law, striving to refer everything back to Our Lord Jesus Christ, recapitulare omnia in Christo, under the aegis of St. Thomas Aquinas.
Consequently:
They will study to become thoroughly acquainted with the writings of the Angelic Doctor and particularly the Summa Theologica, where they will find the most reliable nourishment for enlightened faith, profound piety, and effective, ardent preaching.4