FIRST ARTICLE: WHETHER THE FATHER IS A PRINCIPLE

State of the question. The difficulty arises because the Father is not the cause of the Son and therefore it seems that He cannot be the principle of the Son. It would also follow that the Son proceeded from a principle and would therefore be created, or at least that there were priority and posteriority in God. That which is later depends on that which is earlier, and dependence implies imperfection, which cannot exist in a divine person.

Reply. Nevertheless the Father is a principle. This is of faith since the Father is defined by the Council of Florence as "the principle without principle."[376] In many earlier councils, especially in the Sixth Council of Toledo, the same doctrine was defined: "We confess the unbegotten and uncreated Father, the font and origin of the entire Trinity, with whom there is not only paternity but also the principle of paternity." St. Augustine says: "The Father is the principle of the entire Deity."[377]

St. Thomas explains the meaning of the word "principle" in the body of the article and in the reply to the first objection. A principle is nothing other than that from which something proceeds. For example, a line proceeds from the initial point, a series of numbers proceeds from unity, the light of day proceeds from the aurora. But the Father is He from whom the Son and the Holy Ghost proceed in God. Therefore the Father is a principle and this not in a metaphorical but the proper sense. This is a simple explanation of the meaning of "principle."

Reply to the first objection. This will be made clearer by contrast with the meaning of cause, for as Aristotle himself remarks, "The meaning of principle is more general than cause."[378] Thus we say that the point is the principle of the line and not its cause. For the term "cause" (especially an extrinsic cause) seems to imply the diversity of substance and dependence of one on another, but this is not implied in the term "principle." Hence, although the Greeks in speaking of God used the two terms 'arche' and 'aitia' the Latin doctors never use the word "cause," restricting themselves to the term "principle." The reader is referred to the reply to the first objection.

Reply to the second objection. The Latins do not even use the expression "principle" of the Son and the Holy Ghost because this implies a certain subordination. The Son is said to be the principle from a principle, light from light, and the Holy Ghost is similar in His own way. The beautiful text of St. Hilary is quoted here: "The Son is not less because the one being is given to Him." The Father and the Son both possess subsisting being itself, yet the Father communicates this being to the Son. Analogically, two brothers possessing something in common communicate to each other certain gifts.

Reply to the third objection. Here the objection that principle is derived from priority is solved. But in God there is no priority and no posteriority. I distinguish the major: principle is derived from priority according to the use of the word, let it pass; according to its formal significance, I deny; for principle does not denote priority but origin. In God, however, there is the relation of origin without priority.[379] Certainly there is no priority of time because the processions are eternal; nor is there priority of nature because the divine nature is numerically the same in the Father and the Son and the relation of paternity is not conceived without the opposing relation of filiation. Relative things are simultaneous in nature and in the intellect since one is in the definition of the other. The Father is not constituted by something absolute, as is the man who begets before he begets. In God, the Father does not become the Father, but of Himself and from all eternity He is the Father and He is formally so constituted by the subsisting relation of paternity, whose correlative is filiation, by which the Son is constituted. So it is with the three angles of an equilateral triangle.

In question 42,[380] speaking of the equality of the divine persons, St. Thomas says: "(In God) dignity is absolute and pertains to the essence. As the same essence which is paternity in the Father is also filiation in the Son, so the same dignity which is paternity in the Father is filiation in the Son. But in the Father this dignity is according to the relation of the giver; in the Son it is according to the relation of the receiver." But to receive subsisting and infinite being in itself is not something less perfect than giving it. In the equilateral triangle the second angle constructed is not less perfect than the first, and for the second angle to receive the total area is not less perfect than for the first angle to communicate it. Hence the term principle notionally belongs to the Father. The term principle, however, is also used essentially with respect to creatures, and in this case it is common to the three persons.