As a prelate rising towards the leadership of his order of Augustinian hermits, Giles of Viterbo had a special interest in defending the procession of the Holy Spirit from the Father and the Son, since ‘Augustine established the Filioque’.Footnote ¹ As a man of letters in the age of renewed humanism and, perhaps even more forcefully, as an heir to Renaissance hopes for a renewed learning which would reconcile various strands of human intellectual and religious life, one surely capable of effecting a reconciliation between Greek Eastern and Latin Western Christianity, Giles had an opportunity to review the tradition of scholastic argumentation on the subject with fresh eyes.Footnote ² Participating in the Sentences-commentary tradition at the beginning of the sixteenth century, Giles already had four centuries of commentators behind him,Footnote ³ and since Peter Lombard had devoted the first book of his treatise to questions regarding the Trinity, commentators on his Sentences encountered the Filioque question early. A well-worn interpretative tradition grew around the Filioque doctrine in the universities. The Western commentators were all, however, largely without access to many original texts which explained the Orthodox reasons for finding fault with the Western insertion of the words Filioque into the Nicene-Constantinopolitan Creed. For the Eastern position, Latin commentators relied mainly on John Damascene's De fide orthodoxa in a Latin version which, since the early thirteenth century, had been reorganised and read as an Eastern predecessor to Lombard's Four Books of Sentences.Footnote ⁴ What occurred in Giles’ era was the re-emergence of the Platonic dialogues and an intellectual perspective which was closer to that of the early church Fathers. Further, his age had developed faith in the support which the classical texts, particularly the myths and poetry of ancient Hellenism, lend to discovering the revealed truth of sacred scripture.

Educated at Padua, Giles was a product of the Aristotelian scholastic tradition. As an Augustinian hermit, his spiritual father was Augustine, but he was also a beneficiary of the renewed study of Plato and classical humanism.Footnote ⁵ Giles’ writings show that he shared the methodology of his scholastic predecessors but was not a blind follower in their footsteps. In a Renaissance tradition which made frequent gestures of good will towards the Greek East, Giles effected a commentary on the Filioque which was more conciliatory on this perennial controversy than those of his Western predecessors.

Peter Lombard (c.1100–1160)

The opening words of the treatment of the Filioque in the first book of the Sentences of Peter Lombard, the scholastic theologian who became bishop of Paris, leave no doubt about his position: ‘Here it must be said that the Holy Spirit is from the Father and the Son and proceeds from the Father and the Son, which many heretics have denied’.Footnote ⁶ Peter begins his defence of this position by citing scriptural texts which mention the ‘Spirit of the Son’ and the ‘Spirit of Christ’ and Christ's words about the Spirit, ‘whom I will send to you from the Father’.Footnote ⁷ Peter follows with passages containing phrases which are frequently adduced in opposition to the Filioque, such as ‘the Spirit of your Father’, and ‘whom the Father will send in my name’, and finally the best known, ‘who proceeds from the Father’.Footnote ⁸ Lombard concludes, however, that even those texts which seem to deny the Filioque, when properly understood, confirm that the Spirit proceeds from both the Father and the Son. In the same chapter he acknowledges that the Greeks hold the Spirit's procession from the Father only, and to account for this he refers not only to the principal scriptural texts seeming to refute the Filioque like John 14:26 and 15:25, but to the original wording of the Nicene-Constantinopolitan Creeds, and the anathema pronounced by the first four ecumenical councils against anyone who teaches anything different, aliud, or proclaims anything otherwise, aliter, about the faith of the Trinity than what they have taught and proclaimed.Footnote ⁹ Peter also mentions Pope Leo III's own transcription onto silver plates of the text of the Creed without the Filioque.

In light of historical developments in the West since Pope Leo's day and in the spirit of his commentary's arguments pro and contra, Peter engages in theological rationalising and immediately adds that the Latins interpret the aliud of the anathema as meaning not ‘other’ but ‘against’, and the aliter not ‘otherwise’ but ‘to the contrary’. This argument, which is still voiced in modern polemics, is of course meant to justify the making of additions to the Creed, provided that they are not in violation of the rule of faith. Finally, Peter reuses from Augustine the argument that when Jesus says in the Gospel that the Holy Spirit proceeds from the Father, he does not mean that he proceeds from only the Father.Footnote ¹⁰ The point again is to argue that it was permissible to add what is not considered contradictory to the truth of scripture. So Peter, in the first chapter, bases his support of the Filioque on a claim that he is appealing to the proper sense of the matter and not to the words alone.

Peter's second chapter contributes to what was to become arguably the main traditional appeal for a mutual acceptance by East and West of the truth of the Spirit's procession, even if the words each party uses differ from one another. Peter outlines the framework that it fell to later writers to develop. The point rests on drawing an equivalency between the phrase ‘Spirit of the Son’, which the Greeks do acknowledge, and ‘Spirit from the Son’, which the Latins acknowledge in addition. Peter then adduces texts from what he accepted as four Greek Fathers which state that the Spirit is from the Son.Footnote ¹¹

Since throughout the medieval schools and into the seventeenth century, to produce a commentary on Peter Lombard's Sentences was the traditional rite of passage for students seeking the magisterium or teaching licence in theology, virtually all Western theologians learnt those basic arguments and built upon them. For the purposes of the present study, two principal, somewhat divergent, commentators who were contemporaries of one another will help set Giles’ treatment in relation to his many Western predecessors.Footnote ¹²

Bonaventure (1217–1274)

The Sentences-commentary on book 1, distinction 11, by Bonaventure illustrates the line of argument from a scholastic theologian following strongly in the Augustinian tradition before Giles. He also shows the degree of rigidity in defence of the Filioque which many commentators reached. In the one article consisting of two questions which he devoted to the distinction under study, Bonaventure reviews several standard objections to the Filioque and presents standard refutations. His conclusions summarise much of the Western argumentation and resolution of the question which Giles was to inherit. He notes that there have been different understandings by the Latins and the Greeks of the act of the Spirit's procession. They include, for example, different ideas of spiration. Bonaventure says the Latins have emphasised this divine act not so much as exterior breath (flatus exterioris), as the Greeks have done, but as interior love (amoris interioris) between the Father and Son.Footnote ¹³ In the second question Bonaventure emphasises the single distinctive way in which the Spirit proceeds from Father and Son, and there is an argument for a singular principle at work, which had become a standard qualification of the Filioque doctrine: ‘The Holy Spirit proceeds from the Father and the Son, not insofar as they are distinct Persons, but insofar as there is in them one fecundity of the will, or one active spiration.’Footnote ¹⁴ Bonaventure's commentary could be a fitting example of a conciliatory approach in that it seeks to acknowledge a procession from Father and Son which nevertheless functions through a unified divine act. But Bonaventure does not dwell on the possibilities of integrating the divergent positions. He takes a more judgmental, political tone in claiming that the problem arose in the way the two sides professed their understanding differently from one another. The Latins, he states, have operated in truth, necessity and authority, and the Greeks in ignorance, pride and pertinacity.Footnote ¹⁵ Under that critical shadow Bonaventure asserts that the early conciliar prohibitions about professing the faith ‘otherwise’ still allow valid statements to be added to the Creed.

Thomas Aquinas (1225–1274)

In his Sentences-commentary on book 1, distinction 11, Thomas Aquinas also treats many of the issues Giles was to treat, and while he defends the Filioque, he avoids Bonaventure's criticism of the Greek motivation in refusing to accept the Latin addition to the Creed. Thomas devotes four articles to distinction 11 of book 1. The first article makes passing reference to twelve arguments against the Filioque. These include first and foremost an acknowledgement of the Father as the simple, perfect, unique and essential source of all things, since the Western position must retain this essential doctrine. Thomas also presents arguments which were more vigorously resisted in the West. These include analogies used by opponents of the Filioque, such as one arguing that, just as the procession of a physical spoken word proceeds not from the word in the mind of the speaker but from the speaker himself, so too the procession of the divine breath (Spiritus) proceeds not from the intellectual Word of God (the Son) but from him who generates that Word (the Father). Thomas also cites what was perceived as a standard argument of the Greek position, namely John Damascene's distinction between affirming the Spirit as being ‘of the Son’ but not ‘from the Son’.Footnote ¹⁶ To all of these Thomas gives a short dismissal, frequently by offering counter-analogies, such as Augustine's analogy of the Holy Spirit proceeding from the mutual love of the Father and Son.

To answer John Damascene's differentiation between the scriptural ‘Spirit of the Son’ and the non-scriptural ‘Spirit from the Son’, Thomas follows Peter Lombard in claiming that with reference to God the two phrases must be equivalent. Thomas, however, knows that the passages which Peter Lombard cited from Galatians, such as ‘God has sent forth the Spirit of his Son into your hearts’, do not stand as a self-evident defence of the Filioque or a sufficient proof-text that the Spirit proceeds from the Son as well as the Father.Footnote ¹⁷ He presses the matter by arguing that when the genitive ‘of his Son’, Filii sui, is construed in this case, it cannot be construed in any way other than as expressing the condition of origin, since condition of origin is the only relation which distinguishes the persons of the Trinity.Footnote ¹⁸ So the phrase Spiritus Filii is taken to be equivalent in meaning to Spiritus a Filio.Footnote ¹⁹ Thus, according to Thomas, the Greeks agree with the Latins in essential meaning but not in words.

The remainder of Thomas’ discussion takes up three technical matters, the same three as Giles was to address. In article 2 Thomas argues that the procession from the Father and Son is nevertheless from a singular entity inasmuch as the two divine persons are functioning as one in some essential quality (inquantum sunt unum). Following on this assertion in article 3 he argues that in the case of spiration the Father and Son are one not simply in essence or nature but in the power of spirating spirativa potentia, which ‘means the [divine] essence in the function of this specific property [of spiration]’ (dicit essentiam sub ratione talis proprietatis). This is the power which Bonaventure called spiratio activa. Last, in article 4 Thomas discusses, in light of the multiple sense of the Spirit's procession owing to the Filioque but the singular sense owing to the inquantum unum, whether there should be said to be one spirator or two spiratores. Thomas again treats a theme and the same line of arguments Giles was to inherit but also critically evaluate, accepting some positions but rejecting what he considers to be inadequate acknowledgment of a single spiritive principle at work.

Thomas, for example, refuses to draw a parallel between the doctrine that there is, in spite of the Trinity of persons, only one creator and one initium, and the position that there is one spirator. Instead, he favours arguments in support of the alternative position: as the Father and Son are spirantes, so too they are spiratores. Thomas argues for the absolutely firm plural of verbal nouns as well as participles even when the act they point to is produced by one principium and multiple agents.Footnote ²⁰ Those are all topics Giles treats in his commentary, and he will be shown to reach a conclusion which is more conciliatory than that of Thomas.

Giles of Viterbo (1469–1532)

Giles’ chapter 104 of his Sentences-commentary on book 1, distinction 11, has a four-part subheading: ‘The Spirit Emanates also from the Son. How They [Father and Son] Spirate as One. In What [Quality] They Are One. They Are Both One [Spirator] and Multiple Spiratores.’Footnote ²¹ This indicates a fidelity to the Filioque doctrine but also considers the three related points which seek to give abundant validity to the singularity of the divine act of spiration. Giles will stress that the procession of the Spirit from Father and Son is accomplished in a manner whereby the divine persons are as one (inquantum unum sunt). He will also show that the Father and Son are one in the power of spirating (vis spirandi), which he acknowledges as the divine essence in the specific function of spirating. Third, he will show that it is equally proper to speak of one spirator as of two spiratores, according to whether the speaker has in mind the mutual vis spirandi or the individual divine persons. In this emphasis he surpasses the limits of mutuality and conciliation reached by Bonaventure and Thomas Aquinas.

Giles begins by setting the controversy in a historical, epic context, invoking the pseudo-Etruscan legend of which he was enamoured, that pagan polytheism began in Etruria and moved to Greece and Asia Minor, whereas the Judaeo-Christian religion began in Asia and moved into Italy. Then he notes, with not a little irony, that a great question arose between the Greek and the ‘Etruscan’ Christians about the origin of Love, namely, the Holy Spirit.Footnote ²² Giles acquired much of his Etruscan lore from a forged manuscript of the fifteenth-century Italian Annio da Viterbo.Footnote ²³ For Giles, this lore is not simply a piece of High Renaissance dramatisation of ancient history but an argument in favour of the primordiality and respectability of the East as the seedbed of monotheism and Christian revelation. With this kind of introduction to the controversy, Giles is also validating the use of pre-Christian ancient wisdom to support the later Christian revelation in the tradition of Eusebius’ Praeparatio Evangelica.

In his place in the commentary customarily devoted to the scholastic ‘it appears’ (videtur), the contrary position which the commentator then refutes, Giles presents only the standard argument against the Filioque, that neither the language nor the doctrine is stated in scripture. He makes reference to (ps.) Dionysius that in fact ‘nothing should be ventured’ (nihil audendum) to attempt to capture the mystery of the Spirit in a definition which goes beyond what has been recorded. Giles, however, adds to this ad mentem Platonis, saying that readers of Plato's Timaeus know that nothing at all should be affirmed absolutely, except what the sacred oracle has affirmed.Footnote ²⁴ Later in the treatise he repeats the principle more strongly, with support from other Platonic texts:

In this context, he states explicitly the reason for the opposition to the Filioque: ‘Now the sacred writings do not state that the Spirit flows from the Son but only from the Father; so it should not be said by the Vatican Pope and his Roman Council that he proceeds from the Son.’Footnote ²⁶ He adds the standard reference to John Damascene, that scripture speaks of the Spirit of the Son but not Spirit from the Son, which viewpoint, he observes, the Greeks have steadfastly maintained.Footnote ²⁷

Giles’ acknowledgement of the absence of the Filioque in scripture but its explicit reference to the Spirit's proceeding from the Father conforms to a standard opening procedure in the Latin scholastic tradition of which Giles was a beneficiary. He probably did not know of the Greek patristic and Byzantine theology beyond that, however. Maximus Confessor's or Gregory Palamas’ detailed reflections on the procession of the Spirit from the Father, for example, are not present in Giles. But Giles was able to act on his aim of invigorating what he considered to be a tired scholastic methodology, weighed down by its own record of abstract dialectical complexity, and getting beyond the already familiar Western sources. He therefore does not simply cite the standard argument; it is also his unique contribution to the Sentences-commentary tradition that he buttresses that argument not from Greek patristic sources but from ancient Platonic wisdom.

When Giles turns to present the contra, the Latin position on the Filioque, he acknowledges first of all that it was the Latins who strove with all their might against the Greeks in insisting that the Spirit must be said to be not only of the Son but from the Son.Footnote ²⁸ He adduces traditional elements of the scholastic argument for the procession of the Spirit from the Father and Son. First, there is the claim that order of origin is the only distinguishing element among the immaterial persons of the Trinity. He states this more generally than did Thomas Aquinas, noting that immaterial things must have an order among them if they come forth from the same source. If both Son and Spirit come forth from the Father alone, they would not be distinguished:

The argument need not proceed this far, however. Even John Damascene, no supporter of Filioque, maintained a simple distinction in the manner of originating from the Father, in that the Son draws his origin from the Father by generation and the Spirit draws his origin from the Father by procession, but that the difference between the two modes ultimately remains a mystery.Footnote ³⁰ Giles knows the basic outline of that argument, but he reminds readers that he spoke about the Father's power of generation as analogous to the power of spiration but distinct from it, much as the scholastics had distinguished generation as according to the mode of the intellect and procession as according to the mode of the will. Giles was heir to that tradition of distinguishing the Son's and the Spirit's modes of drawing their respective origins from the Father. Thus, after mentioning in passing two perceived dangers of not acknowledging the Filioque, Arianism and Sabellian modalism, Giles advances to what had already long become the principal way of understanding the procession of the Spirit from Father and Son and consequently main Western argument for the Filioque in the commentaries.Footnote ³¹ This understanding relies on attempting to define two different modes of the Son's and the Spirit's coming forth, emphasising that the Son is born in the mode of the Father's perfect knowledge of himself and the Spirit in the mode of mutual love between the Father and Son. And this divine Love comes forth from both understanding and recognition. As Love, therefore, the Spirit must emanate from the Word in the mode of understanding, as well as the Father who utters the Word of his mind eternally. As Giles puts it, ‘Love always comes forth from knowledge and recognition. For nothing can be loved unless it be recognized by some reason, and so things that lie hidden from us cannot be loved. Wherefore since the Word arises in the mode of wisdom and understanding, Love cannot take its origin except from it.’Footnote ³² The definition of the Word as arising ‘in the mode of wisdom and understanding’ recalls Thomas Aquinas’ emphasis on the generation of the eternal Word as the word of the divine mind (verbum mentis), from which the Spirit of intimate Love proceeds.Footnote ³³

Then, just as he did with the presentation of the Greek position, here Giles seeks support for the Latin position with additional proof from the theologia platonica. He appeals to the Parmenides and the Republic, which were considered to support the unity of God in the first instance and the real distinction of divine persons in the other. Then Giles has readers recall that Dionysius warned against venturing anything about the Spirit (nihil audendum). John Damascene, however, cautioned about holding only to the words of the sacred oracles. What if the sacred oracles, then, can shed light on the question? He therefore reminds readers that the Cratylus teaches that the Son is the ‘child of mighty intelligence’ (a symbol for the Father here), and the Symposium teaches on the genealogy of Love:

Giles then returns to cite the strongest elements in his list of Western arguments. The sacred oracles matter nothing, he says, in light of the divine Son's own testimony about himself. This is Giles’ preamble for citing Gospel passages which are traditionally seen as proof-texts of the Filioque. The main text is John 16:14, ‘The Spirit will glorify me because he will receive of mine.’Footnote ³⁵ Giles interprets this by noting, ‘these words give witness to the same thing about the Holy Spirit as what the Son says about himself when he says, “All things have been given to me by my Father, that is, ‘from him I am born’, and so the Spirit ‘will receive of mine’, that is, he will proceed from me”’.Footnote ³⁶

Giles concludes his presentation of the Roman position with the defensive line of argument e silentio which Augustine originated, namely that scripture's silence about the Filioque, the fact that scripture does not expressly declare that the Spirit is from the Son, is not to be taken to mean that the Spirit proceeds only from the Father. When the Son says the Spirit proceeds from the Father, he does not mean that he does not proceed from the Son too. Giles adds that it is, however, to be accepted that the Spirit does not proceed from the Son principally or chiefly (praecipue).Footnote ³⁷ Giles therefore ends this part of the commentary with a statement which, although it defends an understanding of Filioque and thus supports the Western theology, when so positioned, also allows Giles to emphasise what is equally true about the Greek position, as well as to limit possible excesses in the Western line of argument: ‘We attribute the chief right of flowing to the Father therefore, who is the only person who does not receive from elsewhere, but whatever he possesses he possesses of himself.’Footnote ³⁸

Following that section which is equivalent to the contra of scholastic commentary, where Giles presented the Latin position, he is prepared for the conclusio, where he gives a most conciliatory reply to John Damascene's and the Greek position. He first dismisses two opinions about the Greeks which he considers patently false: some say that the Greeks understand the faith badly; others say that the Greeks are irritated at not having been invited to participate in the Council (of Florence) but that they approve of the theology secretly.Footnote ³⁹ These charges will not stand, and for Giles the conciliatory tone rises quickly to a climax. That (Greek) nation, he states, in all the world have been either the discoverers or promoters of every kind of branch of learning, and they seem therefore most worthy of protection and defence rather than accusation or summoning to trial. Further, they have been the pre-eminent leaders and teachers even of the Latin writers.Footnote ⁴⁰ So there should be a way to understand the validity of their position on the Holy Spirit, and by this Giles means John Damascene's avoidance of the Filioque as dangerous and erroneous, ‘which we [Orthodox] do not say, not because it cannot be said but because it is not found in scripture’.Footnote ⁴¹

Just as important is what the Orthodox do say according to John Damascene, ‘not from the Son but through the Son’.Footnote ⁴² Giles argues that, ‘in order to acknowledge and protect the parts of the whole Church, we Latins should embrace the Greeks as brothers and not try to cast them out, they who have produced the most fruitful and most celebrated part of the Christian people’.Footnote ⁴³ If we consider their argument, he suggests, we will perhaps find the Greek teaching not only not repugnant but even harmonious with our position on the Filioque.Footnote ⁴⁴ Giles here follows Augustine into the area of the Latin case where the Greeks have considered it too sophistic and unwarranted to follow, in claiming that when the Greeks say that the Spirit proceeds from the Father, they actually mean from the Father principally; they do not really deny that the Spirit proceeds from the Son but only that that procession is not by the power of the initium which only the Father has of himself. They mean the Spirit proceeds from the Son only by that power which the Son receives from the Father. This is precisely Giles’ way of affirming the Spirit's procession through the Son (per Filium) as closely as he can while still affirming the Filioque. Summarising the position this way, Giles’ suggestion that close scrutiny of the issue will reveal that the Greek position harmonises with the Latin has as much to say about the Latin position as about the Greek. That is to say, Giles wants to explain the Filioque doctrine in such a way as to emphasise a unity of source, and he wants to explain the Greek position as describing the Son's participation as an agent in sending the Spirit into time and the world.

Giles still speaks of the power of spiration which the Son received from the Father and so is still voicing a Western position. He therefore shows that he has knowledge of the general position of the Greeks without yet appropriating the many Fathers who expounded on the per Filium, including Athanasius, Basil, Gregory of Nyssa, and Maximus Confessor, and even Western Fathers Tertullian, Hilary of Poitiers, and Marius Victorinus.Footnote ⁴⁵ This absence of direct Greek patristic sources resembles that of Peter Lombard himself, for whom John of Damascus is virtually the sole voice of the Christian East. This absence limits Giles’ ability to present important patristic distinctions on the question. Maximus Confessor, for example, presented an argument that was on the other side of Augustine's coin, as it were, arguing that when the Latins say that the Spirit proceeds from the Father and Son, they still differentiate the essential procession from the Father from that derivative procession which is from the Son, since not even the Latins fail to see that the sole cause μιὰν ατίαν of the Spirit is the Father. Maximus used the Greek verb κπορεύεσθαι of the essential procession from the Father and προιἐναι of the progression in the passage of the Spirit, namely the Father and the Son.Footnote ⁴⁶ Giles uses six different verbs for the Spirit's proceeding from the Father (procedere, manare, dimanare, provenire, nasci, exoriri) but with no apparent distinction among them. Zeal for variety seems to be behind Giles’ less technical use of the various verbs. Further, Gregory Palamas distinguished between the procession of the hypostasis of the Spirit, which is that procession only properly attributed to the Father, and the procession of the energies of the Spirit, which is accomplished through the divine nature of the Son. Giles appears only to know that the formula ‘through the Son’ is defended by John Damascene, and that suffices for him, although it is not necessary for him to have acquired even that teaching directly from John, as it was held at the Council of Florence that Thomas Aquinas and other scholastics accepted the wording ‘through the Son’ as the same as ‘from the Son’.Footnote ⁴⁷

Giles thus makes his presentation of the Greek position not in light of the details of the Greek Fathers per se, but on arguments he derives from the procedure of the Latin Sentences-commentaries on the question. But he does inform these from his reading of the Platonic dialogues and declare that readers must explore charitably what the Greek resistance to the Filioque means theologically. Especially, he continues, since the topic under discussion is Love itself, ‘what good is it to practise strife and hatred?’Footnote ⁴⁸

The remainder of Giles’ treatment of distinction 11 forms a second article focusing on the three technical aspects of the Spirit's procession. Giles continues strongly in the spirit of conciliation, as his aim regarding the first aspect is to show that while the claim is that the Spirit proceeds from the Father and Son, those two persons of the Trinity spirate as one. Second, he shows that Father and Son spirate as one in that very vis spirandi which the Son receives from the Father but which only the Father has of himself, and third that it is possible to find truth in both notions of one spirator and plural spiratores. As before, Giles is not intending to argue in favour of the Greek case against the Latin. Had he attempted that he would have failed because he did not know the Greek theology of the procession of the Spirit from the Father alone, with no place for a spirative power shared between Father and Son. Giles’ attempt, however, is nevertheless to show that the Greek understanding, in several respects manifestly different in perspective from the Latin position, is in accord with true doctrine. Many a late Latin theologian seeking to be conciliatory simply attempted to reinterpret the Greek position as identical to the position held in Rome. In making his demonstration, particularly in his second article, however, Giles shows his ability to select between alternative teachings in the repository of scholastic argumentation and also to consider what is true about positions apparently at variance.

Explaining how Father and Son spirate as one is intended traditionally to clarify and refine what is meant and not meant by the Filioque. Giles observes that when the Latins profess that the Spirit proceeds from the Father principally but also from the Son, they seem to be holding that there is a plurality of sources of the Spirit. This, however, would violate the doctrine that there is one initium of the Spirit's proceeding, since acts of God are not attributed to the divine nature but to individual persons within the Trinity. Giles notes that in light of this problem a distinction is customarily maintained between form and agent in the origin of the Spirit. The Latins, he says, depend on not treating the question of spiration simpliciter. It actually requires holding a singularity and plurality together: ‘If the agent be regarded, since there are two persons, it must be said that they act as a plurality, but if the form and the principle of acting is observed, since there is one power of bringing forth the Spirit, they are not as a plurality but as one source (initium) of the flowing Spirit.’Footnote ⁴⁹ Giles, however, knows that there is another way of looking at the matter, and he considers it to be the stronger. What he presents as the better explanation is the position presented by Bonaventure, which does indeed require considering the matter of spiration simpliciter. First of all, Giles notes, it must be maintained that God acts as one being. To make that assertion is to point to the principle of divine action (ratio agendi) and not the individual divine person as the agent (agens) of divine action.Footnote ⁵⁰ The Spirit is professed as proceeding from the Father principally, not because the Father has something the Son lacks, but because the Father has everything ex se and the Son does not. But because acts of God are attributed to individual persons, when God is spoken of as acting as one, as in the case of spiration, then the individual persons must not be acting as individuals. So the Father and Son's action is as one in Love's procession. If their individual persons are thought of, however, then it is possible to speak of Filioque. In this way Giles downplays the distinction between plural agent and singular initium, stressing instead that the two individual persons are not acting as individuals when they spirate the person of Love.

Giles then addresses inquantum sunt unum, the essential corollary to the teaching that Father and Son spirate as one. For the question remains: ‘In what principle do the two divine persons spirate as one?’ It surely is not the divine nature itself, Giles quickly replies, since even the Spirit has that and then the Spirit would be the initium of itself. Giles lists four qualities in which the Father and Son are united. There is the Love by which they are united, that is, the Holy Spirit itself. There is the act of spiration, for Father and Son in this understanding are both agents acting singly. There is the notion of Fatherhood and Sonship in which, since it is interrelational, the one cannot exist without the other. Finally, there is the power of spiration which Father and Son each have. Giles calls this power spirandi vis and spirandi potestas, but by this he means the same as what Thomas Aquinas called spiritiva potentia. Father and Son, Giles argues, are united in all those things, but there is a problem when it comes to spiration. What causes Father and Son to be united in the spiration of the Holy Spirit can be neither the Spirit or Love itself nor the act of spiration itself. They cannot be the cause of their acting as one, Giles notes, simply because a thing cannot be the cause of itself. Nor are Father and Son united through a common notion; for Fatherhood and Sonship, although mutually dependent, are yet distinct from each other. So the uniting principle is the very power of spirating which they share. Now if a reader asks just what the power of spirating is, Giles says he must refer the reader to what he said at length about the vis generandi. Here he summarises by saying it is the same as the divine essence but with an added purpose, which the Spirit does not share in even though he partakes in one divine essence. This is equivalent to Thomas’ definition of his spiritiva potentia, which, as mentioned, Thomas said means the divine essence in the function of such a property (as spiration). It is to be wondered whether this tautological definition satisfied Giles or the scholastics who preceded him. They seem resigned to it because they inherit it and bequeath it, especially in an environment in which the Filioque had become doctrine by unilateral authoritative declaration in the West.

To conclude his commentary on distinction 11, Giles shows significant independence in demonstrating that it is proper to speak about a single spirator as well as multiple spiratores. He begins with the premise that, since the West professes that the Father and the Son spirate, it would seem that there are two spiratores. Giles, however, resists the propriety of speaking of multiple spiratores and says that he reaches a different conclusion. He draws support from analogies offered by other divine names as, for example, the three persons of the Trinity. When it is said that they create, the plural of the verb is used (creant). Similarly, the persons may be described by the plural of the participle as creating ones (creantes). But those plural forms notwithstanding, it is not said that there are three creators (creatores). Giles turns to grammatical analysis. First he observes that some people insist absolutely on a plurality of spiratores. The reasoning for this, however, leads only to a partial and incomplete truth. For they hold that, since the act of spiration involves more than one divine person, then all words denoting that action, but particularly verbs and all other parts of speech derived from verbs, should be in the plural. There is support for this in scripture's ‘I and the Father are one’.

But opinion is divided, Giles observes, since others who may agree about verbs being plural disagree about the substantives even when they are derived from verbs, as in the case at hand with the noun spirator. They argue that it must be determined whether the word in question denotes the substance of a thing or only something added to a substance. He draws support from Plato's Sophist which distinguishes between substantives and action-words. In the case of spirator, the noun, the reference is to the Form, that is, the vis spirandi which serves as the single essential unifying principle of spirating in both persons. Giles concludes that, if this is the understanding, then the noun spirator is rightly in the singular.Footnote ⁵¹

This acknowledgement is consistent with Giles’ conciliatory mission which characterises his entire commentary, Giles concludes virtually every chapter of his commentary by seeking to express the truth in alternative positions regarding many tenets on the mystery of God. Also as customary, the conciliatory resolution is where Giles makes the greatest use of analogies drawn from Platonic texts. ‘We conciliators’, he says, ‘intercede among our Latins not to let this disputation be the seedbed of hatred.’Footnote ⁵² Giles first says that, given the two arguments above, proponents of a singular spirator should remember the advice given in Plato's Statesman and Laws about not altering the truth of the holy oracles. Since Genesis 1:1 in the Hebrew actually gives a plural form for the substantive in naming the creator elohim and matches that plural subject with the singular verb bara, scripture in this case presents the opposite of the scholastic argumentation summarised above, which, relying on the translation of the scripture into Latin, defends the plural of verb forms and the singular for substantives when speaking of divine acts. So Giles first cautions about applying definitive rules of speech to divine matters. He rejects the argument that requires the plural spiratores which finds support in the Gospel text, ‘I and the Father are one’, which Aquinas used, since alternative scriptural texts can be found leading to the opposite conclusion.

Then, having worked to refute the logical necessity for the plural, Giles ends this chapter with an acceptance of the plural as well as the singular, noting that because proponents of the plural maintain that divine action relates to the individual persons and not the one divine nature, ‘even though Plato perhaps did not see it this way, let it be as they teach’. For Giles the matter depends on the intention of the speaker: ‘And so we will say that spirator can be said both singular and plural, if we but pay attention to the agents in the one form and the principle of acting in the other.’ That is to say, since the principle must first and foremost be considered, there is no error in saying that there is one spirator. But for the reasons given about the plurality of the divine persons who are the agents, it is right also to speak of two spiratores. And Plato's myth about Eros originating from Poros and Penia applies to this. He ends by saying that, since the term Filioque has been accepted, he will also accept plural spiratores of the Holy Spirit.Footnote ⁵³

In a rare reference to the discussion of the Filioque in Giles’ Sentences-commentary, John O'Malley made three important observations in passing in his monograph on Giles more than forty years ago. He noted, first, Giles’ expression of confidence that the Greek's doctrine of the procession of the Holy Spirit was actually in agreement and accord with the Latins’ and, second, Giles’ advice towards a ‘calm discussion of theological differences with the Greeks’, seeking to embrace them rather than cast them out. He added, however, as a third observation, that ‘Giles later may not have been so convinced of the Greeks’ orthodoxy, or at least of the admissibility of the formula “per Filium”, as he was at the time of the Sententiae’.Footnote ⁵⁴ On the first point, the present study has shown that Giles went beyond configuring the Greek position to the Latin but was interested in discovering a genuinely conciliatory position to which all parties possessing true doctrine contributed. He lacked details from the Greek patristic tradition, but he sought to find guidance in the prisca theologia of Plato. To the second observation, the present study has shown how Giles’ optimism on a reconciliation to be achieved by reasoned discussion in a spirit of charity did not result in capitulation for its own sake but removed much of the rigidity of his medieval predecessors. To the third observation, it is acknowledged that Giles lived and wrote in a post-conciliar, post-Byzantine-era Rome and, as he moved higher on the administrative ladder, even being considered papabilis for a time, his need to speak for the Latin position became more insistent.