Sacrae Theologiae Summa IIA: On the One and Triune God

This English translation, The One and Triune God (De Deo Uno et Trino), is meant for those who want to learn scholastic and Thomistic theology. The four volumes of B.A.C. contain treatises that cover all the basic dogmas of the Catholic faith and it does it in a detailed and scholarly way, with a heavy reliance on the teaching of St. Thomas Aquinas. One advantage of this Summa is that it gives the student the "theological note," that is, the grade of certitude for each thesis. Here you will learn what is a defined dogma of the Church, what is theologically certain, and what is just a theological opinion. That is important in order to know what level of assent is required for Catholic teachings, such as can be found in the Catechism of the Catholic Church which, since it is for all the faithful and is not a theology textbook, does not, for the most part, give the theological note or doctrinal level of the various truths of the faith. The classical division of the treatise De Deo is into two parts-De Deo Uno according to his nature or essence, and De Deo Trino according to the persons which are always handled in this order. This division should be preserved. First of all, because the order of knowability of divine things so far as we are concerned demands it, since "the essentials, as a theological principle affirms, for our knowledge are prior to ideas." And although many of them can be presupposed as having been treated in natural theology, still there is value in treating them again from the point of view of revelation. The revelation which God has given to us about himself also demands the same thing. For in a way suited to the human mind God first of all, clearly and explicitly, revealed those things that pertain to the unity of the divine essence rather than what pertains to the trinity of persons, the highest mystery of the essence of God and the divine life, so that we might gradually and eventually come to some knowledge of the trinity.