WHETHER EXISTENCE BELONGS TO A PREDICAMENTAL RELATION FORMALLY ACCORDING TO ITS BEING IN THE SUBJECT OR ITS BEING WITH REFERENCE TO ITS TERMINUS

The relation's being in the subject ("esse in") is not the foundation of the relation but it is the relation itself in the general nature of an accident and not under the special aspect of a relation. The reply of the Thomists is that existence does not belong formally to a predicamental relation according to its being with reference to its terminus ("esse ad") because according to this being with reference to another ("esse ad") the relation abstracts from existence and could be a relation of reason. Existence, however, belongs to a predicamental relation according to its being in a subject, that is, its "inesse"," or its inherence in the subject. Since, however, as we shall see below, in God the "esse in" cannot be an accident, but must be the divine substance, it follows, according to St. Thomas, that there is one being in the Trinity for the different divine relations. Suarez, on the contrary, thought that a relation had its own proper existence and therefore he taught that there were three relative existences in God. Similarly he taught that there were two beings in Christ because he denied the real distinction between the created essence and being. For St. Thomas there was but one being for the three divine persons and one being in Christ.

This distinction between the "esse in" of a relation and its "esse ad" is clearly explained by St. Thomas: "The relation itself, which is nothing else than the reference of one creature to another, has one kind of being inasmuch as it is an accident and another being inasmuch as it is a relation or order to another. Inasmuch as it is an accident it has its being in a subject, but not as it is a relation or an order, for as a relation it has being exclusively with reference to another, a something passing over to another and in some way assisting the thing to which it is related."[206] Thus the "esse in", which is something the relation has in common with all accidents, gives title to reality to the relation's "esse ad".[207]

From various examples, especially in the supernatural order, we shall see that this concept of relation is of great importance. In Christ the hypostatic union is the real relation of the dependence of the humanity of Christ on the person of the divine Word. "The hypostatic union is that relation which is found between the divine and human natures... . This union is not really in God but is only a relation of reason; but it really is in the human nature, which is a kind of creature. Therefore it is proper to say that it (the hypostatic union) is something created."[208]

Similarly, in the Blessed Virgin Mary the divine maternity is a real relation to the person of the incarnate Word, and because of its terminus this real relation belongs to the hypostatic order and transcends the order of grace. Hence it is commonly held that the Blessed Virgin Mary was predestined to the divine maternity before she was predestined to the fullness of glory and grace. It should be noted, however, that the person of the Word does not acquire a real relation to the Blessed Virgin but only a relation of reason because the relation of God to creatures is only a relation of reason. So also St. Joseph's great dignity of foster-father of the incarnate Word is a relation. Finally, our adoptive sonship is a relation to God the author of grace; it is a participation in the likeness of the eternal filiation of the only-begotten Son.