I have found the larger work from which that quotation comes, and I couldn’t find anywhere that St. Gregory says that the Son participates in the hypostatic procession of the Holy Spirit (in fact, most mentions of through the Son in that work seem to be referring to the economy), so I’m not so sure that’s what he meant. If I recall, even Marduk’s opinion is that the Son does not cause the person of the Holy Spirit.
He doesn’t mention it in any other part of that work, but that isn’t really important. The point is that he does mention that the Son is the “intermediary” in the procession of the Holy Spirit, and he does so quite explicitly. He says, in preface to this portion of the text that I quoted, that he is describing the causes of the Divine Persons themselves, their origins, and he most definitely puts the Son “between” the Father and the Holy Spirit.
I suggest that the only reason you’re having difficulty with what he means is that you are coming to the text with the presupposition that he
can’t mean the filioque, despite the fact that his plain language not only indicates the filioque but actually rules out any notion that he’s speaking in terms of economic or “energetic” manifestation. He even uses the nature of this “intermediary Procession” to guard the “only-Begotteness” of the Son, which surely proves that he’s speaking of direct causal relations in the Trinity and not some external manifestation.
At any rate, I’m not so sure that the issue is quite as simple as the patristic witness being clear evidence for the filioque. That relies on a lot of odd grammatical assumptions, firstly that αιτία is equivalent to both source and cause in Latin, and that the Greek speaking Fathers only meant source when using αιτία in that context (and that they were thinking with the Aristotelian metaphysics which provided the framework for medieval scholasticism, which is not apparent at all), and that ex patre filioque is grammatically equivalent to ex patre per filium.
Actually you have my points mixed up, which is likely my fault in not being clearer.
Aitia is not equivalent to both source and cause in Latin, but rather in Greek it is a term that can be used broadly or narrowly. Narrowly it is synonymous with source, and this is how it is often used by the Greek Fathers; this isn’t an odd grammatical assumption, but simply a fact, as can be seen in the quote of St. Gregory’s where he speaks of the Father alone with the term “cause” (aitia in the original), yet clearly states that the Holy Spirit is “by the Son”. Broadly, however, it can have many meanings depending on the context, and this can be seen in its many uses in Aristotle and other philosophers. It is the Latins, not the Greeks, who use cause in this broad sense theologically.
As for ex Patre Filioque being grammatically equivalent to ex Patre per Filium, they are not equivalent and I wouldn’t claim that they are. Ex Patre per Filium is a more problematic expression, however, because it does not imply consubstantiality of the Holy Spirit. “Per” does not simply mean “through” as in “passing through” in Latin, it can also mean “by” and imply metaphysical distance, such as the President acting through the army. When we say such a thing we mean precisely that the President himself is
not where the army is fighting, and it is much the same in Latin. If the Latin were say “per Filium” it could naturally be understood to mean that the Father gives the directive, and the Son produces the Holy Spirit. The best way to say that the Father Himself breathes forth the Holy Spirit through the Son is “ex Patre Filioque”, which is why that is the preferred term in Latin.
For reference, in the Creed when it says of the Son “by whom all things were made”, the Latin is “
per quem ómnia facta sunt.” We know that while the Godhead works together with one Energy in all things, the creation of the world is appropriated to the Word specifically, and in the Latin this is done by saying “
per”. Obviously we don’t want to appropriate the Procession of the Holy Spirit to the Son alone, so why would we accept this term?
In addition, we see that both sides had to grapple with seemingly contradictory statements from the Eastern Fathers. For example, St. John of Damascus produced both of these statements in the same paragraph:
Actually these statements aren’t much of a problem for Latin theology, though it is for the Photian. The main difficulty the Latins had is that both ekporousis and proinai were translated as “proceeds” in Latin (and in English, BTW) despite having very different meanings. Latin simply doesn’t have a word that matches ekporousis, which literally means “from the mouth” and is taken to represent the coming forth from a source a la “from the horse’s mouth”. Of course the word used in the Creed is ekporousis, but the Latin renders it with the closest it can offer which is “procedit” which simply means “moving forward from” and has no implication of source, just as proceed has no implication of source in English.
continued…
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Even the Philippines and East Africa!
I don’t know how to describe it.