SECOND ARTICLE: WHETHER THERE ARE NOTIONS IN GOD

In this article St. Thomas explains in opposition to Praepositivus of Cremona that it is necessary to express the relations in the abstract, and that the relations in the abstract are called personal properties or notions. Thus paternity is said to be a notion or the objective reason denoting the person of the Father, and filiation likewise is the notion or the proper reason denoting the person of the Son, and similarly procession is the notion denoting the third person.

The reason for having recourse to the abstract notions of paternity, filiation, etc., is that our intellect apprehends God not as He is in Himself as a most simple being, but in the mirror of sensible things, that is, according to our method of knowing sensible things. The simple forms of sensible things are signified by abstract terms, for example, animality, humanity, whereas the suppositum is signified by concrete terms, such as this animal, and this man.

As St. Thomas says,[369] because of their simplicity we designate divine things by abstract terms, and by concrete terms because of their subsistence. Thus we speak of God and, the Deity, of wisdom and a wise man, of paternity and the Father. But we add that God is His own Deity and the Father is His own paternity. Otherwise we would not be able to reply to the heretics who ask how the three persons are one God and how they are three. For the person of the Father there is a special reason since the person of the Father is actively referred to the two other persons by the two relations of paternity and active spiration. These two relations cannot be reduced to one, otherwise filiation and passive spiration would be identified and thus there would be only two persons. Thus we must admit two notions for the Father, namely, paternity and active spiration, and the latter is common to Him and to the Son.