In this article, in order to establish that I understand the deficient Pneumatology of the West and how they invoke Augustine to their defense, I am going to intentionally make their case from the writings of Augustine in as few words as possible.

If you do not understand why I am doing this or its importance, please read the Preface to this series of articles.

With the preceding out of the way, let’s make the case that Augustine was a Pneumatological thinker in line with the Council of Florence’s definition of the Spirit’s causation:

[T]he holy Spirit is eternally from the Father and the Son, and has his essence and his subsistent being from the Father together with the Son, and proceeds from both eternally as from one principle and a single spiration. We declare that when holy doctors and fathers say that the holy Spirit proceeds from the Father through the Son, this bears the sense that thereby also the Son should be signified, according to the Greeks indeed as cause, and according to the Latins as principle of the subsistence [i.e. existence/production] of the holy Spirit, just like the Father. (Sixth Session of Council of Florence)

It has been said that the council was, fundamentally, reiterating what Augustine himself said:

[T]he Father is a beginning in relation to the Son, because He begets Him; but whether the Father is also a beginning in relation to the Holy Spirit, since it is said, He proceeds from the Father, is no small question…[T]he Father and the Son are a Beginning [Principium] of the Holy Spirit, not two Beginnings; but as the Father and Son are one God, and one Creator, and one Lord relatively to the creature, so are they one Beginning relatively to the Holy Spirit. (On the Trinity, Book V, Par 15)

As we can see, Augustine appears to state there is one principle which in Latin means “beginning,” who is identified as both the Father and the Son. The following inference, possibly justified, is made concerning Augustine’s thought in Par 15–

The eternal origins of the Spirit pertain to a single principle/cause, that being the Father and the Son. We should note that Par 15 in the beginning appears to talk about origin/cause, because it makes reference to how the Son is begotten (which is a matter of origin). However, the statement pertaining to “Principium” does not actually state that origin is in mind, but rather “beginning…relatively to the creature.” Nevertheless, “so are they one Beginning relatively to the Holy Spirit” must be a reference that both Persons are in the same way the cause of the Spirit’s existence as they would be in the cause of mankind receiving the Holy Spirit.

Let’s grant that the inference is justified. This inference appears born out in Augustine’s Tractate 99 of the Gospel of John. In few words, this tractate sums up arguments overarching the entirety of On the Trinity. I will parse Par. 6 through 9 of Tractate 99 in detail and iterate what they appear to say in agreement with Florence:

  1. Some one may here inquire whether the Holy Spirit proceeds also from the Son. For the Son is Son of the Father alone, and the Father is Father of the Son alone; but the Holy Spirit is not the Spirit of one of them, but of both…[Parses Matt 10:20 and Gal 4:6]

Augustine begins by showing that nominally the Spirit is the Spirit of the Father (Matt 10:20) and the Spirit of the Son (Gal 4:6). If the Spirit is named as belonging to both the Father and Son, then, Augustine reasons, the Spirit proceeds from both.

Are there, then, two [Spirits], the one of the Father, the other of the Son? Certainly not…7. And for no other reason, I suppose, is He called in a peculiar way the Spirit; since though asked concerning each person in His turn, we cannot but admit that the Father and the Son are each of them a Spirit; for “God is a Spirit,” [John 4:24] that is, God is not carnal, but spiritual. By the name, therefore, which they each also hold in common, it was requisite that He should be distinctly called, who is not the one nor the other of them, but in whom what is common to both becomes apparent.

Augustine now makes the point that because the Father is God, then He is Spirit. Likewise, the Son is God, then He is Spirit. The Spirit is the same essence as the Father and the Son, so He is called Spirit. We can iterate the same logic as to why the Spirit is called “Holy.” Obviously, the Father and Son are Holy. In short, the Spirit is what the Father and Son are, because He is of their essence with no diminution.

Why, then, should we not believe that the Holy Spirit proceeds also from the Son, seeing that He is likewise the Spirit of the Son? For did He not so proceed, He could not, when showing Himself to His disciples after the resurrection, have breathed upon them, and said, Receive the Holy Spirit. For what else was signified by such a breathing upon them, but that from Him also the Holy Spirit proceeds?…[Discussion of “virtue”]

Augustine’s logic is that if procession belongs to God the Father, this means procession of the Spirit is a property belonging to Divinity. Because the Son is God, it is therefore true to say the procession likewise belongs to the Son. The temporal procession appears to be used as an example of the eternal procession, if we infer the Florentine reading of this passage. A rather long discussion of “Virtue,” which is “the Power of the Holy Spirit” (Luke 6:19) follows in the exact same vein.

  1. If, then, the Holy Spirit proceeds both from the Father and from the Son, why said the Son, “He proceeds from the Father?” [John 15:26]

Augustine appears to anticipate one objection, that being, why does John 15:26 explicitly only make reference to the Spirit proceeding from the Father? His answer is as follows:

Why, do you think, but just because it is to Him He is wont to attribute even that which is His own, of whom He Himself also is? Hence we have Him saying, “My doctrine is not mine, but His that sent me.” [John 7:16] If, therefore, in such a passage we are to understand that as His doctrine, which nevertheless He declared not to be His own, but the Father’s, how much more in that other passage are we to understand the Holy Spirit as proceeding from Himself, where His words, He proceeds from the Father, were uttered so as not to imply, He proceeds not from me?

In short, Augustine is saying that Christ mentioned only the Father as it pertains to the Spirit’s procession, because Christ considers everything that belongs to Himself as belonging to the Father. So, Augustine reasons, this does not imply that the Spirit does not proceed from Him any more than “My doctrine” is not “Mine” as it pertains to Christ. It is “Mine” (the Son’s) but also “not mine, but His” (the Father’s).

But from Him, of whom the Son has it that He is God (for He is God of God), He certainly has it that from Him also the Holy Spirit proceeds: and in this way the Holy Spirit has it of the Father Himself, that He should also proceed from the Son, even as He proceeds from the Father.

On the surface, “even as He proceeds from the Father” appears to say that the Spirit proceeds from the Father and Son in the same exact way—that being, eternally.

In connection with this, we come also to some understanding…why the Holy Spirit is not said to be born, but to proceed: since, if He also were called by the name of Son, He could not avoid being called the Son of both, which is utterly absurd. 

Augustine now anticipates the second objection to his teaching, as I said before is as follows:

Augustine’s logic is that if procession belongs to God the Father, this means procession of the Spirit is a property belonging to Divinity. Because the Son is God, it is therefore true to say the procession likewise belongs to the Son.

The objection to the preceding teaching is that if being begotten belongs to the Son, and He is God, then being begotten is a property belonging to Divinity, therefore the Spirit should be also begotten just as the Son is. Augustine replies that the logic pertaining to procession is not the same as eternal-causation-via-being-begotten:

For no one is a son of two, unless of a father and mother…


In short, the Spirit cannot be begotten, because (Augustine presupposes) the Spirit proceeds from the Son. And, if procession logically the same as being begotten, that would make the Spirit both proceeding from the Son and the son of the Son–but with the same Father who begets both the Son and Spirit and proceeds the Spirit. This is illogical and not possible. One can be a grandson, of a son, of a father—but not a son of another son, as well as being a child of that other son’s father.

But the Holy Spirit proceeds not from the Father into the Son, and then proceeds from the Son to the work of the creature’s sanctification; but He proceeds at the same time from both: although this the Father has given unto the Son, that He should proceed from Him also, even as He proceeds from Himself.

The preceding statement is hugely in favor of the Florentine formulation of the Filioque. The Father alone is not the cause of the Holy Spirit, but the Father and the Son “at the same time,” or in the words of Florence, “a single principle and a single spiration.”

The following image, where it says “Latin Church,” appears to illustrate what Augustine is saying here:

Screenshot 2020-02-28 at 6.42.51 PM

An Orthodox Christian may object that the preceding statement pertains to eternal origins, because “the work of the creature’s sanctification” is the point at issue, and one would have to infer that the temporal procession in every way reflects the eternal procession—a statement Augustine does not explicitly make. For now, we are going to handwave this away and say that Augustine is speaking about eternal origins, because of On the Trinity, Book 15, Par 47. 

Before parsing that passage, let’s finish Tractate 99:

And as little can we say that the Holy Spirit is not the life, seeing that the Father is the life [John 5:26], and the Son is the life [John 14:6]. And in the same way as the Father, who has life in Himself, has given to the Son also to have life in Himself; so has He also given that life should proceed from Him, even as it also proceeds from Himself. But we come now to the words of our Lord that follow, when He says: “And He will show you things to come. He shall glorify me; for He shall receive of mine, and shall show it unto you. All things that the Father has are mine: therefore, said I, that He shall take of mine, and shall show it unto you.” [John 16:14-15]

Augustine concludes the Tractate making “an argument from Life.” This is similar to the “God is Spirit” argument. If the Father is said to be Life and the Son the same, therefore the Son has everything the Father has. Because nowhere in the Scriptures is the Spirit called “Life,” therefore He does not share this quality self-susbsistently as the Father and Son do. Thus, it is necessary to infer that the Father takes what is His and gives it to the Son, which obviously includes the ability to “proceed” the Holy Spirit.

Granted, this is a bad argument. For one, we are aware that the Son says the doctrine is not His own, but yet it is—so, why would it be necessary to infer that the Spirit is not the Life simply because it is nowhere explicitly stated? John 6:63 and Rom 8:2 mitigates against Augustine’s point here, though technically it is possible to infer that the Spirit gives life through the Son, but He is not the Life in of Himself. Ambrose also explicitly calls the Holy Spirit “the Spirit of Life” (On the Holy Spirit, Book 1, Par 58), which shows that Augustine’s own teacher did not concur. Lastly, there are Trinitarian issues with the statement if taken at face value. Do the Two or Three Persons have three separate “Lifes” per hypostasis? Of course not. Life must belong to the divine essence, which means each hypostasis shares the same “Life.”

So, while we find Augustine’s argument here not entirely airtight, and it is actually troubling if taken literally (which I do not think is the case), that is not the point. We are making the argument that Augustine believes the Spirit eternally proceeds from the Father and the Son. From this passage, it appears we can draw the conclusion that the Spirit must proceed from the Father and the Son, because the Spirit cannot derive Life from Himself—but only from the Father and Son. This would be akin to saying Love does not come from itself, but from the relationship between a Lover and a Beloved. This latter example, is used by Augustine as well.

Before ending this article, I want to attempt extrapolating the Florentine Pneumatological doctrine from what is in my estimation, Augustine’s most “Filioquist” passage—Book 15, Par 47 of On the Trinity. The passage is as follows:

Are we therefore able to ask whether the Holy Spirit had already proceeded from the Father when the Son was born, or had not yet proceeded; and when He was born, proceeded from both, wherein there is no such thing as distinct times?

At first glance, the answer would seem to be “no.” However, Augustine attempts speculating that though the Spirit is eternal, we can presumably get some glimpse at His eternal causation. This is an inference of sorts, but a justified one because the speculation of whether “the Holy Spirit had already proceeded from the Father when the Son was born” is an obvious reference to the Son’s eternal origins in reference to the Spirit’s. 

…Wherefore let him who can understand the generation of the Son from the Father without time, understand also the procession of the Holy Spirit from both without time. And let him who can understand, in that which the Son says, “As the Father has life in Himself, so has He given to the Son to have life in Himself,” not that the Father gave life to the Son already existing without life, but that He so begot Him apart from time, that the life which the Father gave to the Son by begetting Him is co-eternal with the life of the Father who gave it: let him, I say, understand, that as the Father has in Himself that the Holy Spirit should proceed from Him, so has He given to the Son that the same Holy Spirit should proceed from Him, and be both apart from time

Just like Tractate 99, Augustine makes the “argument from Life.” It is compelling to believe that eternal origins are at issue, because “from both without time” and “both apart from time” appears to be a reference to eternal origins, including the Son in said origins.  

and that the Holy Spirit is so said to proceed from the Father as that it be understood that His proceeding also from the Son, is a property derived by the Son from the Father. 

In short, “apart from time” the Spirit proceeds also from the Son, because the ability to have the Spirit proceed from the Son “is a property derived by the Son from the Father.” Procession thereby also properly belongs to the Son, because He is Life in the exact same way the Father is Life. The image of the triangle appears to be justified in what we see here.

For if the Son has of the Father whatever He has, then certainly He has of the Father, that the Holy Spirit proceeds also from Him. But let no one think of any times therein which imply a sooner and a later; because these things are not there at all…And the Son is born of the Father; and the Holy Spirit proceeds from the Father principally, the Father giving the procession without any interval of time, yet in common from both [Father and Son]. But He would be called the Son of the Father and of the Son, if — a thing abhorrent to the feeling of all sound minds — both had begotten Him. Therefore the Spirit of both is not begotten of both, but proceeds from both.

Similar to Tractate 99, Augustine explains how the Spirit can proceed from the Father and the Son, but not be begotten by the Father (as this would create a nominal contradiction—the Father and the Son, in order not to be grandfather and Father of the Spirit, must have the Spirit proceed and not beget from both.)

What does it mean that the Holy Spirit proceeds from the Father “principally…yet in common” between the Father and Son? Florence speaks of a single principle, or cause, that being the Father and the Son. On the face, this is be a contradiction. How can a single principle/cause have two parties (i.e. two principles/causes)? However, as Augustine said earlier in the same book:

[T]he Father and the Son are a Beginning [Principium] of the Holy Spirit. (On the Trinity, Book V, Par 15)

Therefore, there must be some way that both the Father and the Son are a principle (in one way), but the Father is solely the principle in another way—otherwise there would be no sense whatsoever in which the Spirit “proceeds from the Father principally.” 

I presume the minds of the Filioquist thinkers deriving their understanding from Florence would reconcile the two by saying the following: 

  1. The Father is the origin of the Son.
  2. The Father and Son are the origin of the Spirit.
  3. Therefore, the Father is the principle cause of the Spirit’s origin in that He is also the origin of the Son, whose existence is necessary for there to be via a single spiration (i.e. causal event) of two separate processions—one from the Father and the other from the Son. 

Again, we can see the preceding accords with the triangle image earlier in the article. I do not think the preceding is an unfair summary of Roman Catholic thought. The Concise Oxford Dictionary of the Christian Church in its summary of the “double procession” states:

…theologians argue that as both Latins and Greeks hold everything common to the Father and the Son except the relationship of Paternity and Sonship, the Spiration of the Holy Spirit, in which this relation is not involved, must be common to both

The preceding pertains to what Thomas Aquinas calls “a relation of principle.” In other words, the Father is the principle of the Son by relationship of Paternity and Sonship, and the Father and Son is the principle of the Spirit, because the Father confers procession to the Son and by relationship, no to the Spirit, because His relationship is not that of Father and Son.

Why must we conclude the Spirit comes from a “relation of principle” within the Godhead? Due to procession not being something that contradicts 1. The shared essence and 2. The relational difference in Persons of the Father and Son, therefore 3. The Father and Son must “proceed” the Spirit as there would be no relational/“nominal” (as explained above) contradiction. 

It is a logical necessity because its logically possible. This is the Filioquist argument.

Yet, despite ascribing to the double procession, Aquinas elsewhere concedes that the Father stands in some sense, as it pertains to being a principle, before and above the Son–but this too is a nominal, relational difference.  In a highly technical disputation, Aquinas concurs with the following statement:

The principle whence a thing proceeds exercises a certain authority over that which proceeds from it as from a principle. If then one divine person proceeds from another, for instance, the Son and the Holy Spirit from the Father, there must be in the Father some authority over the Son and the Holy Spirit: and thus, since authority is a kind of dignity there will be a dignity in the Father that is not in the Son and the Holy Spirit.

By adding the following proviso:

Authority in the Father is nothing but the relation of principle. (De Potentia, Question 10, Article 1, Point 17)

In short, the Father in effect is a principle above/before a principle; or in other words the Personal principle that is the origin of the Son, as well as a dual-Personal principle (Father + Son), is the principle/origin of the Holy Spirit. 

As I postulated above, there is some sense that “the Father is solely the principle in another way” than the “one” principle/spiration (which includes both the Father and Son) of the Holy Spirit’s procession–by the criteria that Augustine and Aquinas give. According to Aquinas, the principle of the Father is purely relational—i.e. He is the Father of the Son, which by being unbegotten makes him a principle above/before the Son, who is only part of the principle of the Holy Spirit. The principle of the Spirit’s causation is in addition to principle of the Son’s causation, as the principle of the Son precedes that of the Spirit, whose principle requires the Son to exist.

Elsewhere, “St Thomas” parses the interesting Latin term “auctor,” which in Latin theology means “Author” or “Originator” explaining “that the name auctor denotes the principle which does not derive its being from another [quoting Aquinas]: ‘This is why, even though [while] the Son can be called principle [of the Holy Spirit], only the Father is named auctor.’ The name auctor thus denotes the relation of principle found in the person of the Father.” (Giles Emery, The Trinitarian Theology of Thomas Aquinas, p. 159

(Note: I used the above source to inform my presentation of Aquinas and I cite the same primary sources.) 

As we can see, the entire Roman Catholic dogma of Aquinas (and presumably Florence) hinges upon what is, in reality, two-principles. A principle for the Son, which pertains to a relational difference between Father and Son, and a secondary principle of the Spirit, which pertains to the Father and Son—or in the words of Aquinas himself, quoting what (from what I can tell) was a forgery ascribed to Gregory Nazianzus:

We believe the holy Trinity, namely, the Father without a principle, the Son, however, a principle from a principle, the Father, but the Holy Spirit with the Son as principle, to be one God throughout all and over all. (Against Greek Errors, Book II, Chap 24)

Such a scheme preserves the relation of principle which in effect puts the Father “on top” of the God head, the originator and principle of all. From all the preceding, the triangle illustration from earlier still seems to fit best.

Yet Aquinas complicates things by offering his own illustrations that look different. In the previously mentioned book, in chapter 30, quotes another forgery, ascribed to Athanasius:

Indeed, just as he who pulls the head link of a chain pulls also its middle link, and against the Father, the opposite extremity, so he who blasphemes also against the Spirit, the third person, blasphemes also against the Son, the middle link, and against the Father, the opposite link, the head of the chain of the triune, distinct, unconfused divine order…The Father from himself, as origin of the triune divine order, through the medium of his begotten Son established by a natural property the term of this very order in the third person, the spirated Spirit.

And then offers the following interpretation:

For if the Holy Spirit were not from the Son, the Holy Spirit would no more be the term of the Trinity than the Son, nor would the order of the Trinity be likened to a chain [by Pseudo-Athanasius] but rather to a triangle.

Aquinas then quotes a forgery ascribed to Cyril of Alexandria to bolster his point:

Cyril says: “As the arm and hand exist naturally from the body and prolong it, and as the finger extends naturally from the hand, so from God the Father, as his arm and hand, the Son, naturally arises by generation God from God, and from the Son as from the natural hand of the Father God the Holy Spirit called finger is produced, flowing forth naturally. 

From the preceding, we can surmise that the term “double procession” is misleading when made into an illustration. In effect, there is a definite sequence in Aquinas’ mind of: 


  1. Father
  2. Father begets Son
  3. Son proceeds Holy Spirit (presumably concurrently with the Father acting through the Son as an agent.)

As we can see, Aquinas rejects, the triangle–a single point of origin (the Father) with the Son being begotten on one hand and the Spirit proceeding from the other. Ironically, this is the illustration Irenaeus offers, calling the Son and the Spirit the “Hands of God.” (cf A.H, Book V, Chap 28).

So, while the first image of a “kind” of triangle is what the Council of Florence appears to be communicating, this may even be misleading. Florence merely reiterates Constitution 1 of the Council of Lyons (1274):

We profess faithfully and devotedly that the holy Spirit proceeds eternally from the Father and the Son, not as from two principles, but as from one principle; not by two spirations, but by one single spiration. This the holy Roman church, mother and mistress of all the faithful, has till now professed, preached and taught.

Aquinas died shortly before attending that council. He personally worked as a Papal theologian at the Dominican stadium in Orvieto when he wrote Against Greek Errors. It is beyond unlikely that the theologians of Lyons represented an idea that was not pervasive in 1263, when Aquinas offered his illustrations. So, it is within the lens of Aquinas Roman Catholics must understand Augustine’s words: 

[T]he Holy Spirit proceeds from the Father principally, the Father giving the procession without any interval of time, yet in common from both [Father and Son].


But the Holy Spirit proceeds not from the Father into the Son, and then proceeds from the Son to the work of the creature’s sanctification; but He proceeds at the same time from both.

On the face of it, Aquinas’ illustration appears to be “the Holy Spirit proceeds from, the Father into the Son and then proceeds from the Son,” and not “at the same time from both.” I will allow those more learned in Aquinas to come more specifically to his defense, but I will simply say in deliberately making the Roman Catholic case that Aquinas was only looking at “one half” of the “single spiration.” If the Father gives to the Son the ability to proceed the Spirit identically to His, then the Father’s procession of the Spirit must be identical to the Son’s. So, the illustration should be corrected to look like this so it shows a double procession:


It should go without saying that either illustration contradicts Orthodox doctrine, which knows of no doubling of principles/causes of the Spirit:

[T]he Father is the only cause of the Son and the Spirit, the one by begetting and the other. by procession (Maximus’ Letter to Marinus)

[W]e speak also of the Spirit of the Son, not as through proceeding from Him, but as proceeding through Him from the Father. For the Father alone is cause. (Exposition of the Orthodox Faith, Damscene, Book I, Chap 12)

[T]he Father is the foundation and the source of the Son and the Spirit, the only source of divinity, and the only cause. (Council of Blachernae, Fifth Anathema)

As Aquinas himself conceded: 

On the other hand the Greeks employ the word ‘cause’ more absolutely when speaking of God, and indicate origin only. (De Potentia, Question 10, Article 1, Point 8)

But, being that Aquinas taught “the Son originates the Holy Spirit,” (Against Greek Errors, Book II, Chap 22) quoting a forgery of Athanasius’ 54th letter, it is clear that Aquinas believed there to be, in fact, two principles (Father, and Father and Son) and two causes (Father, and Father and Son)—and only for technical reasons pertaining to grammar “by reason of the unity of the property [shared essence between Father and Son] that is signified in this word ‘principle’” can we speak of the Spirit originating from a single principle (Summa, Part I, Question 36, Article 4). 

Due to forgeries and bad translations of the Damascene’s exposition, which obfuscated the impossibility of the Spirit having two origins/causes, Aquinas developed the theology that became the doctrine of Florence. Being that Aquinas’s doctrine is based on forgeries, we should presume that his logic and that of Florence should contradict Augustine.

But, as we have seen, an argument can be made that it does not. The existence of forgeries does not, by default, put Augustine and Aquinas (and thereby Lyons and Florence) into contradiction. The forgeries could have easily been made to recast the Greek Fathers’ doctrine into an Augustinian one.

So, having treated the preceding topic thus, we will test the interpretations against the entirety of On the Trinity. From this, we can properly evaluate Augustine’s Pneumatology and see if the Roman Catholic Church truly preserves the Augustine’s parsing of the Filioque.