St. Thomas on why there are only three Persons when there are four mutually opposed relations in the Holy Trinity

by Dr. David Fleischacker

In the first part of the Summa Theologicae, question 30, article 2, St. Thomas is presenting the intelligible grounds for the existence of three and only three Persons of the Holy Trinity. It is a rather fruitful passage to come to understand, and it reveals some of the real power of the analogy that St. Thomas was using to understand the Holy Trinity. If Tertullian and St. Augustine are famous for asking “three what?” And answered “three persons,” St. Thomas now asks the further question, “Why three persons?”

Could an analogy actually help to explain this point? The better the explanatory capacity of an analogy, the more it is going to help us understand. This analogy was based upon the interior procession of the act of understanding to the act of the word, and then from word to will/love. 

St. Thomas shows that if we suppose this set of processions to be in God, then there are three persons. And, one can even go on and say what these three would be like.  The two processions result in four relations, since each procession results in two mutually opposed relations.

Though the general question regards why only three persons exist when there are four relations, within this context, another question emerges.  Why are the two relations of the second procession [the procession of love] distinct from the two relations based on the first procession [the procession of intellect]? Earlier in the Summa, St. Thomas had proposed that in each procession, there are two mutually opposed relations. However, each of the first two relations [filiation and paternity] are not mutually opposed to either of the second two relations [spiration and “procession”]. Hence, how are filiation/paternity distinct from spiration/procession if not seemingly based on mutually opposed relations? The answer requires that one link the two processions, and that the mutually opposed relation of one set be identified with one or both of the relations in the other set.  Thus, spiration is either paternity, filiation, or both; or “procession” (passive spiration) is paternity, filiation, or both.

Here is the main body of that second article that I found particularly interesting:

I answer that, as was explained above, there can be only three persons in God. For it was shown above that the several persons are the several subsisting relations really distinct from each other. But a real distinction between the divine relations can come only from relative opposition. Therefore two opposite relations must needs refer to two persons: and if any relations are not opposite they must needs belong to the same person. Since then paternity and filiation are opposite relations, they belong necessarily to two persons. Therefore the subsisting paternity is the person of the Father; and the subsisting filiation is the person of the Son. The other two relations are not opposed to either of these, but are opposed to each other; therefore these two cannot belong to one person: hence either one of them must belong to both of the aforesaid persons; or one must belong to one person, and the other to the other. Now, procession cannot belong to the Father and the Son, or to either of them; for thus it would follows that the procession of the intellect, which in God is generation, wherefrom paternity and filiation are derived, would issue from the procession of love, whence spiration and procession are derived, if the person generating and the person generated proceeded from the person spirating; and this is against what was laid down above (27, 3 and 4). We must frequently admit that spiration belongs to the person of the Father, and to the person of the Son, forasmuch as it has no relative opposition either to paternity or to filiation; and consequently that procession belongs to the other person who is called the person of the Holy Ghost, who proceeds by way of love, as above explained. Therefore only three persons exist in God, the Father, the Son, and the Holy Ghost.

A hermeneutical note

I would like to focus on the boldface part of the quote above with the following question. Why would linking the the relation of “procession” with Father and Son result in the procession of intellect issuing from the procession of love? One thing I want to highlight is that the inversion takes place when one considers both the Father and the Son to be a result of the relation of “procession”, not just the Father or just the Son. The small clause “or to either of them” results in a similar problem but through a slightly different logical route which I will discuss below.  However, if you notice the next sentence is refering to both the generator and the generated, hence the Father and the Son together.

The Problem

Now to return to the problem. The relation of “procession” regards the relationship of love to that from which it proceeds, the spirator.  St. Thomas is proposing a problem. If one is going to say that the relation of “procession” [as a note, I will put the relation of procession in quotes] belongs to the Father and the Son, then one must say that the procession upon which the Father and Son were based comes from the procession of love. Earlier, he had argued that in us, the procession of love comes from the procession of intellect. So, why would the relationship of the two processions become inverted?

The meaning of procession, relation, and mutually opposed relations

In general, the meaning of procession is to come forth from an origin.  So, the second term comes forth from the first.  Now, in the procession of intellect, what comes forth from the first is an image of the first.  Hence, a word.  Since an image of another that comes forth from that other is the meaning of generation or begetting, this procession is one of begetting or generation.  And, since paternity means “that which generates or begets a generated or begotten, then the relations of the first to the second is that of paternity. Likewise, since filiation means that which comes from another as an image of the other, then the relation of the second term to the first is filiation.

Notice, thus, that paternity and filiation are mutually opposed relations.  They are NOT relations that are equal.  Two friends, for example, are equal in their generic meaning, insofar as they are “friends.” Friend one has a relationship of friendship to friend two.  And, friend two has a relationship of friendship to friend one.  The meaning of friendship in both relations is equal.  Hence, these are not mutually opposed in meaning. In contrast, paternity is defined in an unequal and opposite relationship to filiation.  Hence, they cannot be switched and mean the same thing.

Why the inversion.

Understanding this mutual opposition of the relationships, and how both are based on the same procession, is key to understanding the logic of the problem St. Thomas has presented.

Like paternity and filiation, spiration [active] and “procession” [passive spiration] are each mutually opposed relations based on two different but related processions.  If “procession” (passive spiration) were the same as the Son and the Father, then they come from the spirator. However, if they come from the spirator, then they are based on the procession of love.  However what they “mean” as Father and Son is based upon the procession of intellect, because only this procession gives mean to paternity and filiation, thus one must also conclude that just as they, so the procession upon which they are defined issues from the procession of love.

What about equating passive spiration (procession) with Son? Or with Father?

One could push the exploration of this question however in directions further than that stated by St. Thomas. Instead of identifying passive spiration with both the Father and Son, what happens when it is identified with just one or the other? Well, other, similar problems emerge. One does not immediately conclude to the inversion of the relations of the processions, but one does run into some conflicting problems. For example, if the Son comes both from begetting and spirating, then the Son would then be both a word and something that is not a word (namely love).  Likewise, if the Father was both begetter and spirated, then the relation of the Father and Son would be rather bizarre.  Since the Son would not be in mutual opposition to his spirated Father, he would be one who spirates the Father.  So, the one who the Father begets, is also the one who spirates.  Thus, the Father, through the Son, also spirates, who? Himself.  So, the Father is both spirated and spirator, which conflicts.

One can keep exploring the logic of this confusion, and in every case, conclude that neither one nor both the Father and the Son can be passively spirated (and thus be the relation that St. Thomas calls
procession).
So who is based on spiration and who on procession? 

Hence the Father and the Son are the Spirator, and hence are based on spiration.  The Holy Spirit is spirated and based on “procession.”

What if only the Father or only the Son is based on spiration? 

One could further wonder why are both the Father and the Son linked to spiration, and not just one or the other. In short, conflicting intelligibilities and doctrinal positions emerge when identifying spiration with either the Father alone or the Son alone. Because then one would say that procession is opposed to the one but not the other. Intelligibly, if spiration is equated with the Father, then the Son is opposed to spiration, and not to procession. Thus, the Son is both a word and something which cannot be a word, namely love.  Likewise, if spiration is equated with the Son, then the Father would be in an opposed relation to spiration, thus he would be identical with the relation of procession.  In turn, the Father would be both spirated and begetter.  Thus, as the begetter of the Son, who then spirates the spirated, he also spirates himself by begetting his Son (a problem in reverse from what we ran into earlier).  This means that he is not opposed to spirator, but if the Son is the spirator, and the Father is not, then the Father cannot be spirator. Doctrinally, it means that either the Son or the Father are not distinct from the Holy Spirit, which is opposed to the dogmatic position. 

Thus, what is left is that both must be the spirator.  An analogical explanation which provides the intelligible grounds for the fililoque in the Church creed.

2 Replies to “St. Thomas on why there are only three Persons when there are four mutually opposed relations in the Holy Trinity”

  1. One step that is useful when following a logical path is to clearly state the assumption. This might precede the text in question, but why does Thomas exactly assume paternal, filial, and process features?

    Or, what exactly does he assume without question? We want to be sure he didn’t have the creed in-mind, and then work his way back to the assumptions.

    Finally, as with all analogy, where does it break down?

  2. Re: Mounce

    If I understand your questions correctly, I agree, part of the “logic” of the argument, was developed in earlier questions. The basic assumption is the psychological analogy (the intellectual emantions, etc.). However, one can ask, why this assumption. To answer this, I would say he had to have the creed in mind, because using this particular analogy arises from the search for an explanatory analogical understanding of the Trinity. Without the Creedal basis, one would not be on the search (a search which is clear in St. Augustine’s De Trinitate). One would not be one such a search otherwise, simply because one cannot argue to the existence or even probability of the Trinity via analogies alone. Beyond the search however, the creed also provides the grounds for affirming the validity of the analogy, because the analogy comes to explain, or conclude to the point being explored in the Creed. So, in a way, one can say, if there are the intellectual and volitional emantions in God, then there is a Trinity. However, there would not be any conditions by which one could affirm these emanations without the creed.

    I would argue that some analogies may not need to break down, as happens with metaphors. However, all analogies are limited, and knowing the limits is key — I suppose you could call this a breakdown, but it does not mean it is false. For example, one says analogically that God is unrestricted Being, or Goodness. The meaning of these terms is analogical, however there is nothing in them that is false either (though the person could, I suppose think that these are not just analogies, but the complete comprehension of God, in which case that is false). So, in saying God is a Trinity of three persons, we are understanding these terms analogically, however these have come to possess a revelatory certitude with them. The intellectual emanation is also an analogy, but it does not, at least yet, have a revelatory certitude (or a clear creedal correlate).

    Perhaps by breakdown, you mean “the limits of the explanatory power of the analogy,” and this I am not sure has been fully exhausted yet with this analogy. St. Thomas will show how this analogy can go on and not only explain why there are three persons, but also some of the general features of these persons as well, which then is validated by creed/scriptural/revelatory knowledge of these three Persons. In turn, this gives even more weight to the validity of the original assumptions (namely the intellectual and volitional emanations).

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