THE DIVISION OF ST. THOMAS' TREATISE ON THE TRINITY

IN the prologue (question 27), St. Thomas lays down the order for the whole treatise and the fitness of his distribution of the matter is immediately apparent. He explains: "Since the divine persons are distinguished by the relations of origin (inasmuch as the Son is denominated by His origin from the Father, and the Holy Ghost by His origin from the Spirators), we shall follow the order indicated by the matter itself when we first consider origin or procession, secondly the relations of origin, and thirdly the divine persons."

The treatise, therefore, is divided as follows:

1. Concerning the divine processions (Question 27).

2. Concerning the divine relations (Question 28).

3. Concerning the divine persons (Questions 29 to 43).

Of persons absolutely:

In common: the idea of person, the plurality of persons, the similarities and dissimilarities of the persons, and their knowability by us.

Individually: the persons of the Father, the Son, and the Holy Ghost.

Of the persons comparatively: with regard to their essence, their properties and relations, their notional acts (generation and active spiration); the comparison of the persons with one another with regard to their similarity and equality and their respective missions.

St. Thomas, we see, proceeds according to the genetic method, from that which is better known to that which is less known. For in the Scriptures we read of processions, indicated by the name of the Son, proceeding from the Father, and of the Holy Ghost, proceeding from the spirators, but we do not find the word "person," only the personal nouns, Father, Son, and Holy Ghost. In this way St. Thomas gradually shows that the relations are founded in the processions (for example, filiation is based on passive generation), and that the persons are constituted by subsisting relations. Beginning with what is explicitly revealed, the processions, he finds something that is implicitly revealed and gradually progresses from the indistinct knowledge of subsisting relations and related persons to a defined and distinct idea. These are, as we shall see, explicative processes, or at least subjectively illative, and not objectively illative processes, except in those instances where a new truth is deduced. In general in these first questions the same truth, which is formally revealed, is extensively explained and unfolded.[155]

In the division of this treatise it should be noted that the first two parts are discussed in Questions 27 and 28: the third part, treating of the divine persons, is treated in Questions 29 to 43.

This third part is subdivided into two parts:

1. The persons considered absolutely: a) in common; b) individually.

2. The persons considered comparatively: a) with regard to their essence; b) their properties; c) their notional acts (active generation and active spiration); d) their equality, similarity, and missions.

At first sight it will appear that in Questions 39, 40, 41, St. Thomas seems to begin the treatise anew, treating of the persons in common with regard to their essence, properties, and notional acts; he seems to be repeating what was already said in Questions 27, 28, and 29, about the processions, the relations of origin, and the persons in common.

He is not, however, repeating himself; for what he said earlier in an analytical exposition he explains later in a synthetical exposition, comparing one truth with another and penetrating more profoundly into the matter of the treatise. Many of St. Thomas' commentators, because of the similarity of the matter treated, explain in their commentary on Question 27 the doctrine offered by St. Thomas in Question 39. They follow this procedure for the sake of clarity and brevity, but the more profound and preferable presentation, we think, is that given by St. Thomas.