The Knowledge of the Divine Persons
The Knowledge of the Divine Persons — St. Thomas Aquinas asks: Whether the trinity of the divine persons can be known by natural reason?; Whether there are notions in God?; Whether there are five notions?; Whether it is lawful to have various contrary opinions of notions?.
We proceed to inquire concerning the knowledge of the divine persons; and this involves four points of inquiry:
Article 1: Whether the trinity of the divine persons can be known by natural reason?
Hilary says (De Trin. i), "Let no man think to reach the sacred mystery of generation by his own mind." And Ambrose says (De Fide ii, 5), "It is impossible to know the secret of generation. The mind fails, the voice is silent." But the trinity of the divine persons is distinguished by origin of generation and procession (). Since, therefore, man cannot know, and with his understanding grasp that for which no necessary reason can be given, it follows that the trinity of persons cannot be known by reason.
It is impossible to attain to the knowledge of the Trinity by natural reason. For, as above explained (), man cannot obtain the knowledge of God by natural reason except from creatures. Now creatures lead us to the knowledge of God, as effects do to their cause. Accordingly, by natural reason we can know of God that only which of necessity belongs to Him as the principle of things, and we have cited this fundamental principle in treating of God as above (). Now, the creative power of God is common to the whole Trinity; and hence it belongs to the unity of the essence, and not to the distinction of the persons. Therefore, by natural reason we can know what belongs to the unity of the essence, but not what belongs to the distinction of the persons. Whoever, then, tries to prove the trinity of persons by natural reason, derogates from faith in two ways. Firstly, as regards the dignity of faith itself, which consists in its being concerned with invisible things, that exceed human reason; wherefore the Apostle says that "faith is of things that appear not" (Heb. 11:1), and the same Apostle says also, "We speak wisdom among the perfect, but not the wisdom of this world, nor of the princes of this world; but we speak the wisdom of God in a mystery which is hidden" (1 Cor. 2:6,7). Secondly, as regards the utility of drawing others to the faith. For when anyone in the endeavor to prove the faith brings forward reasons which are not cogent, he falls under the ridicule of the unbelievers: since they suppose that we stand upon such reasons, and that we believe on such grounds.
Therefore, we must not attempt to prove what is of faith, except by authority alone, to those who receive the authority; while as regards others it suffices to prove that what faith teaches is not impossible. Hence it is said by Dionysius (Div. Nom. ii): "Whoever wholly resists the word, is far off from our philosophy; whereas if he regards the truth of the word"---i.e. "the sacred word, we too follow this rule."
Article 2: Whether there are notions in God?
Damascene says (De Fide Orth. iii, 5): "We recognize difference of hypostases [i.e. of persons], in the three properties; i.e. in the paternal, the filial, and the processional." Therefore we must admit properties and notions in God.
Prepositivus, considering the simplicity of the persons, said that in God there were no properties or notions, and wherever there were mentioned, he propounded the abstract for the concrete. For as we are accustomed to say, "I beseech your kindness"---i.e. you who are kind---so when we speak of paternity in God, we mean God the Father.
But, as shown above (), the use of concrete and abstract names in God is not in any way repugnant to the divine simplicity; forasmuch as we always name a thing as we understand it. Now, our intellect cannot attain to the absolute simplicity of the divine essence, considered in itself, and therefore, our human intellect apprehends and names divine things, according to its own mode, that is in so far as they are found in sensible objects, whence its knowledge is derived. In these things we use abstract terms to signify simple forms; and to signify subsistent things we use concrete terms. Hence also we signify divine things, as above stated, by abstract names, to express their simplicity; whereas, to express their subsistence and completeness, we use concrete names.
But not only must essential names be signified in the abstract and in the concrete, as when we say Deity and God; or wisdom and wise; but the same applies to the personal names, so that we may say paternity and Father.
Two chief motives for this can be cited. The first arises from the obstinacy of heretics. For since we confess the Father, the Son, and the Holy Ghost to be one God and three persons, to those who ask: "Whereby are They one God? and whereby are They three persons?" as we answer that They are one in essence or deity; so there must also be some abstract terms whereby we may answer that the persons are distinguished; and these are the properties or notions signified by an abstract term, as paternity and filiation. Therefore the divine essence is signified as "What"; and the person as "Who"; and the property as "Whereby."
The second motive is because one person in God is related to two persons---namely, the person of the Father to the person of the Son and the person of the Holy Ghost. This is not, however, by one relation; otherwise it would follow that the Son also and the Holy Ghost would be related to the Father by one and the same relation. Thus, since relation alone multiplies the Trinity, it would follow that the Son and the Holy Ghost would not be two persons. Nor can it be said with Prepositivus that as God is related in one way to creatures, while creatures are related to Him in divers ways, so the Father is related by one relation to the Son and to the Holy Ghost; whereas these two persons are related to the Father by two relations. For, since the very specific idea of a relation is that it refers to another, it must be said that two relations are not specifically different if but one opposite relation corresponds to them. For the relation of lord and father must differ according to the difference of filiation and servitude. Now, all creatures are related to God as His creatures by one specific relation. But the Son and the Holy Ghost are not related to the Father by one and the same kind of relation. Hence there is no parity.
Further, in God there is no need to admit any real relation to the creature (); while there is no reason against our admitting in God, many logical relations. But in the Father there must be a real relation to the Son and to the Holy Ghost. Hence, corresponding to the two relations of the Son and of the Holy Ghost, whereby they are related to the Father, we must understand two relations in the Father, whereby He is related to the Son and to the Holy Ghost. Hence, since there is only one Person of the Father, it is necessary that the relations should be separately signified in the abstract; and these are what we mean by properties and notions.
Article 3: Whether there are five notions?
A notion is the proper idea whereby we know a divine Person. Now the divine persons are multiplied by reason of their origin: and origin includes the idea of someone from whom another comes, and of someone that comes from another, and by these two modes a person can be known. Therefore the Person of the Father cannot be known by the fact that He is from another; but by the fact that He is from no one; and thus the notion that belongs to Him is called "innascibility." As the source of another, He can be known in two ways, because as the Son is from Him, the Father is known by the notion of "paternity"; and as the Holy Ghost is from Him, He is known by the notion of "common spiration." The Son can be known as begotten by another, and thus He is known by "filiation"; and also by another person proceeding from Him, the Holy Ghost, and thus He is known in the same way as the Father is known, by "common spiration." The Holy Ghost can be known by the fact that He is from another, or from others; thus He is known by "procession"; but not by the fact that another is from Him, as no divine person proceeds from Him.
Therefore, there are Five notions in God: "innascibility," "paternity," "filiation," "common spiration," and "procession." Of these only four are relations, for "innascibility" is not a relation, except by reduction, as will appear later (). Four only are properties. For "common spiration" is not a property; because it belongs to two persons. Three are personal notions---i.e. constituting persons, "paternity," "filiation," and "procession." "Common spiration" and "innascibility" are called notions of Persons, but not personal notions, as we shall explain further on ().
Article 4: Whether it is lawful to have various contrary opinions of notions?
The notions are not articles of faith. Therefore different opinions of the notions are permissible.
Anything is of faith in two ways; directly, where any truth comes to us principally as divinely taught, as the trinity and unity of God, the Incarnation of the Son, and the like; and concerning these truths a false opinion of itself involves heresy, especially if it be held obstinately. A thing is of faith, indirectly, if the denial of it involves as a consequence something against faith; as for instance if anyone said that Samuel was not the son of Elcana, for it follows that the divine Scripture would be false. Concerning such things anyone may have a false opinion without danger of heresy, before the matter has been considered or settled as involving consequences against faith, and particularly if no obstinacy be shown; whereas when it is manifest, and especially if the Church has decided that consequences follow against faith, then the error cannot be free from heresy. For this reason many things are now considered as heretical which were formerly not so considered, as their consequences are now more manifest.
So we must decide that anyone may entertain contrary opinions about the notions, if he does not mean to uphold anything at variance with faith. If, however, anyone should entertain a false opinion of the notions, knowing or thinking that consequences against the faith would follow, he would lapse into heresy.
By what has been said all the objections may be solved.