¹ See especially I Sent., d. 3, q. 1, a. 4; In Boeth. de Trin. q. 1, a. 4; De Veritate [=DV] q. 10, a. 13; and Summa Theologiae [=ST] I q. 32, a. 1.

² See Summa contra Gentiles [=SCG] I, chs. 7-8; ST I, q. 32, a. 1, ad 2.

³ For more on the reach and role of reason in Trinitarian theology, see Emery, Gilles, Trinity in Aquinas (Ypsilanti, MI: Sapientia Press, 2003), 1-32.Google Scholar

⁴ For the “common” in God (including God's absolute perfection) as accessible to natural reason, see ST I q. 32, a. 1.

⁵ See my “Giving Perfections, Receiving Perfections: The Essential Divine Attributes in Aquinas's Trinitarian Theology,” (PhD Diss., The Ponticial John Paul II Institute, 2017), 41-160Google Scholar, where I also give some sense for the parallel path that Thomas lays out with reference to the love that necessarily proceeds in any act of will. For an earlier treatment of these same principles, see Vagaggini, Cyprian, “La hantise des rationes necessariae de saint Anselme dans la théologie des processions trinitaires de saint Thomas,” trans. Evard, J., in Specilegium Beccense. Congrès International de ix^e centenaire de l'arrivée d'Anselm au Bec (Paris: Vrin, 1959), 103-139Google Scholar; Vagaggini, however, comes short of acknowledging the full force of the principles to which he himself calls attention.

⁶ See Milbank, John, “Truth and Vision,” in The Radical Orthodoxy Reader, eds. Milbank, John and Oliver, Simon (New York: Routledge, 2009), 69-115, especially 101-103Google Scholar; Pannenberg, Wolfhart, Systematic Theology, Vol. I, trans. Bromiley, Geoffrey W. (Grand Rapids: Eerdmans, 1991), 287-288Google Scholar; and Hankey, Wayne, God in Himself (Oxford: Oxford University Press, 1987), 134 and 147.Google Scholar

⁷ See Torrell, Jean-Pierre, introduction to Facing History: A Different Thomas Aquinas, by Boyle, Leonard E. (Louvaine-la-Neuve: Fédération Internationale des Instituted d’Ètudes Médiévales, 2000), xxivGoogle Scholar; Malloy, Christopher J., “The ‘I-Thou’ Argument for the Trinity: Wherefore Art Thou?” Nova et Vetera 15 (2017), 113-159CrossRefGoogle Scholar, especially 115-116, 118, and 125-137; and Holtz, Dominic, “Divine Personhood and the Critique of Substance Metaphysics,” Nova et Vetera 12 (2014), 1191-1213Google Scholar, on 1213. For an earlier example, see Masiello, Ralph, “Reason and Faith in Richard of St Victor and St Thomas,” New Scholasticism 48 (1974), 233-243, especially 234-236.CrossRefGoogle Scholar

⁸ While I hope that this point will be enough to show that both of these positions are too problematic to be ultimately tenable, we will not have space to respond in detail to all of the arguments that might be marshalled out in their favor. First of all, we cannot address the texts that each camp cites in support of its position (members of the first camp cite De Potentia [=DP] q. 8, a. 1, ad 12 and DV q. 4, a. 2, ad 5; those in the second camp cite SCG I, ch. 53 and IV, ch. 11; and either camp might also cite DV q. 10, a. 13, ad 2 and In Boeth. de Trin., q. 1, a. 4, ad 6). Elsewhere, however, I hope to show that these texts, which might initially seem to stand as open-and-shut sources of support for these respective positions, are actually far more complicated than they initially appear.

And, perhaps even more significantly, we cannot address ways in which each camp invokes Thomas's teaching on analogy, along with his apophaticism (and so his insistence that, even with faith, we cannot know how God exists, or how God understands) in order to downplay the force of these principles (for some examples of this move, see Emery, The Trinitarian Theology of St. Thomas Aquinas, trans. Murphy, Francesca [Oxford: Oxford University Press, 2007], 185Google Scholar; Matthew Levering follows Emery here in Engaging the Doctrine of the Holy Spirit [Grand Rapids: Baker, 2016], 96n.108). I have addressed this point at length—and I have attempted to account for Thomas's claims in, for example, ST I q. 32, a. 1, ad 2—in “Giving Perfections, Receiving Perfections,” 89-105; and we will speak to it, at least indirectly, at various points as we continue (see especially in n.32 below). For now, however, we can stress that, again, even though we will not be able to speak to every aspect of our two positions, we will see enough to conclude that they are untenable, and that no amount of appeals to analogy, to apophaticism, or to any “proof texts” can make them any more viable.

⁹ Importantly, none of the figures mentioned in n.6 above end up asking this difficult question. Pannenberg merely notes that there is a tension here without any attempt to resolve it. Hankey goes further, arguing that this tension cannot be resolved: for Hankey, Thomas contradicts himself here in a flurry of “incongruities” (God in Himself, 134) and “incoherences” (147). Milbank, finally—to put the matter somewhat crassly—does not so much reconcile the strength of these arguments with Thomas's distinction between faith and reason as invoke these arguments in order to call this distinction (or at least any straightforward reading of it) into question. For more on Milbank on this score, see DeHart, Paul J., Aquinas and Radical Orthodoxy: A Critical Inquiry (New York: Routledge, 2010), 171-196.Google Scholar

¹⁰ I myself tentatively outline two possible approaches to this question—which can hopefully bring us further than can either of the two positions we will treat here—in “Giving Perfections, Receiving Perfections,” 111-114, and in “The Reach of Reason and The Eyes of Faith: Pierre Rousselot and the Question of ‘Necessary Reasons’ in Aquinas's Trinitarian Theology,” forthcoming in Gregorianum.

¹¹ Before beginning, we should stress a basic point: if the arguments that Thomas so consistently lays out from the meaning of absolute perfection to the necessity of the Trinity are, in fact, airtight and logically compelling, then no amount of appeals to the limits that Thomas places on natural reason can make them any less so. These limits, therefore, cannot be invoked in order to deny the conclusions to which these arguments unavoidably lead. Instead, this conclusion could only be denied by showing that, in fact, there is a hole at some point in these arguments—and our main aim here will be to show that no such hole exists (indeed, there is good reason to think that Thomas sees no incompatibility at all between these arguments and these limits, for he often articulates them in immediately adjoining passages. See my “Giving Perfections, Receiving Perfections,” 112-113 for more on this point). Indeed, speaking more generally, there are any number of other considerations which are doubtless relevant and important, but which we cannot treat in any detail here: the distinct ways in which Thomas treats the common the proper in God, the role of “redoublement” in his Trinitarian theology, and the more general distinction and relationship between faith and reason (and between theology and philosophy), just to name a few (plus the role of analogy and apophaticism mentioned in n.8 above). Yet, as important as all of these points are, it remains the case that, if the arguments that Thomas lays out really are as strong as we will contend that they are, then none of these points can be invoked in order to show otherwise. Again, our conclusions here can only be refuted by showing that there is a hole somewhere in the path that, as we will argue, make them unavoidable.

¹² Verbum: Word and Idea in Aquinas (Toronto: University of Toronto Press, 1997), 204Google Scholar; emphasis added.

¹³ Richard's The Problem of an Apologetical Perspective in the Trinitarian Theology of St. Thomas Aquinas (Rome: Gregorian University Press, 1963)Google Scholar is the only monograph devoted entirely to this question.

¹⁴ Problem, 230; emphasis added. Such strong language redounds throughout Problem: see also 188, 226, 302, 307, 308, and 330.

¹⁵ Thus, Richard writes that “the existence and proper predication of the Divine Word” is unknowable apart from Revelation (Problem, 188; emphasis added).

¹⁶ Aquinas: God and Action, third edition (Eugene, OR: Wipf and Stock, 2016), 175-176,Google Scholar quoted on 175; this passage comes at the end of Burrell's reflections on the divine Word on 172-176.

¹⁷ Scripture and Metaphysics (Oxford: Blackwell, 2004), 83n.27.Google Scholar

¹⁸ Thomas Aquinas's Trinitarian Theology: A Study in Theological Method (Washington, D.C.: The Catholic University of America Press, 2003), 76Google Scholar; emphasis added. In a related move, a number of scholars not only argue that we cannot know that a word is necessarily present in every act of understanding; instead, they even argue that, in fact, this necessity is limited to human or creaturely understanding. And so they hold that, if a Word is present in God, then this presence is not required by the structure of understanding-as-such. Cesar Izquierdo gives, and refutes, some examples of this approach in “La theologia del verbo de la ‘Summa Contra Gentiles,’” Scripta Theologica 14 (1982), 551-580Google Scholar, on 570n.54 and 571n.55. We will return to this point ourselves in Section II.

¹⁹ Trinity, Church, and the Human Person (Washington, D.C.: Catholic University Press, 2007), 82.Google Scholar

²⁰ Ibid., 82n.44; emphasis added.

²¹ Trinity in Aquinas, 98; emphasis added.

²² Theologie du Verbe. Saint Augustin et saint Thomas (Paris: Cerf, 1951), 167n.1Google Scholar; emphasis added.

²³ Ibid., 172n.1; emphasis added. See also 175n.3. Paissac also offers some developed thoughts on faith, reason, and the word in ibid., 220-231; yet these final reflections, while often rich, cannot ultimately resolve our question here.

²⁴ Le périchorèse des personnes divines (Paris: Cerf, 2005), 176Google Scholar; emphasis added.

²⁵ See his, “Is the Blessed Trinity Naturally Knowable? St. Thomas on Reason, Faith, Nature, Grace, and Person,” Gregorianum 93 (2012) 113-149Google Scholar; quoted on 149.

²⁶ See, for example, SCG I 44§6.

²⁷ DP q. 9, a. 5; emphasis added here and in all passages from Thomas to follow.

²⁸ Ibid.

²⁹ In Ioan., #25.

³⁰ In Ioan., #26.

³¹ Thomas makes clear in ##26-28 that doing so by no means requires that he paper over the radical differences between human, angelic, and divine acts of understanding; instead, it simply requires that, no matter how radical these differences might be, they cannot open up any space at all for an act of understanding that is simply word-less.

³² Thomas writes that “whenever something that is of the ratio of a thing is taken away, it must be that the thing itself is removed, just as were reason removed, man would be destroyed” (I Sent., d. 26, q. 2, a. 1, ad 3); and, “[f]rom the very fact that something is attributed to anything, everything that is of the ratio of the former must be attributed to the latter” (ST I q. 28, a. 3). Thus, no amount of apophatic or analogous distance between God and creature, and no amount of (rightful) insistence that we cannot know the way in which a given perfection exists in God, can soften the necessity with which all that belongs to the ratio of a given term (as a word belongs to the ratio of understanding) must be present in some way in God if that term is predicated properly of God. This point will be just as relevant when we come to the rationes of a word and of relation with reference to the second camp, and so we must bear it in mind throughout.

³³ Indeed, in addition to the two more striking passages we have treated here, Thomas makes much the same point all through his mature Trinitarian theology: see SCG IV 11§9, 11§10, and 14§3; CT I, 37; DP q. 8, a. 1 and q. 9, a. 9; and ST I q. 27, a. 1 and q. 37, a. 1. Also relevant here—though very different, and quite a bit more complicated—is in Metap., #2539, where Thomas seems to suggest that Aristotle discovered that a word belongs to the ratio of understanding. For more on in Metap., #2539 in this connection, see my “The Reach of Reason and The Eyes of Faith.”

³⁴ SCG IV 11§13.

³⁵ ST I q. 34, a. 1. Thomas makes clear in the same passage that such a “concept of the heart” is an inner word.

³⁶ De rationibus fidei, ch. 3.

³⁷ In Ioan., #28. Thomas makes similar points with great regularity in his Trinitarian theology: see SCG IV 11§11; CT I 42; De rationibus fidei, ch. 3; DP q. 8, a. 1; q. 9, a. 5; ST I q. 27, a. 2.

³⁸ ST I q. 28, a. 1. See also DP q. 7, a. 10, arg. 3 and ad 3.

³⁹ Importantly, we will see in a moment that such real relations necessarily attend not only on procession within a numerical identity of nature, but even on any procession within a shared specific nature.

⁴⁰ Doing so will also allow us to speak more directly to certain members of the second camp, who seem to suggest (at least at times, and not without ambiguity) that natural reason can advance up to, but that it cannot take, the step from procession in God to real relation in God. Paissac, for example, seems to vacillate between suggesting that natural reason falters at the move from procession to real relation and suggesting that it falters at the move from real relation to real distinction (see Théologie du Verbe, 175 and 175n.3). Emery, at least at one point, seems to deny that natural reason can take the step from procession in God to real relation in God: for he draws a line between the existence of the divine Word (which we can know by natural reason) and its “real relation with the entity from which it proceeds” (which he suggests that we cannot know: recall n.21 above). Yet, elsewhere, Emery writes that “word” is “a relative term,” and even that “the notion of ‘word’ implies a real relationship with the intellect that is its principle” (Trinity, Church, and the Human Person, 78-79; emphasis added). Thus, for Emery, real relation enters (at least implicitly) into the very “notion of ‘word’”—from which it seems to follow that, if natural reason can know that there is a Word in God, and if it can know “the notion of ‘word,’” then it can know that there is necessarily real relation in God. Thus, as with Paissac, there is perhaps an ambiguity here. Yet, again, both thinkers seem to insert an unbridgeable gap either at the transition from procession to real relation, or at the transition from real relation to real distinction. We will see here, however, that neither such position is ultimately viable (R. L. Richard had already noted as much, with reference to Paissac, in Problem, 32; Vagaggini puts the same criticism a bit less diplomatically in “La hantise,” 135n.94).

⁴¹ DP q. 8, a. 1.

⁴² Returning to the procession of a word, Thomas also suggests—without using language quite as strong as he does elsewhere—that reciprocal real relation follows on any procession of any word in any intellect: see ST I q. 28, a. 1, ad 4 and q. 28, a. 4, ad 1.

⁴³ I Sent., d. 15, q. 1, a. 1.

⁴⁴ ST I q. 41, a. 4, ad 3. The context makes it clear enough that Thomas is speaking here of real distinction.

⁴⁵ ST I q. 33, a. 1.

⁴⁶ CT I, ch. 52.

⁴⁷ On this note of real distinction, one might object that, in fact, Thomas speaks quite frequently of something proceeding from itself: that is, he claims regularly that “the free is the cause of itself [liber est causa sui].” For ways in which this maxim in no way undermines our claim here, however, see Spiering, Jamie Anne, “‘Liber est Causa sui’: Thomas Aquinas and the Maxim ‘The Free is the Cause of itself,’” The Review of Metaphysics 65 (2011), 351-376Google Scholar, especially 354n.8.

⁴⁸ ST I q. 28, a. 1.

⁴⁹ I q. 28, a. 3.

⁵⁰ See also DP q. 8, a. 2, ad 3: “just as things which pertain to goodness or wisdom, such as intelligence and so on, are really in God, even so that which is proper to a real relation, namely opposition and distinction, is really in God.”

⁵¹ See ST I q. 3, a. 3. Thus, while Thomas is careful to distinguish the common from the proper in God, he here suggests strongly that the logic we are pursuing here (in brief, if a term is predicated properly and analogously of God, then so too must be all that “pertains” to that term) holds in things said of God relatively no less than things said absolutely (such as goodness and wisdom).

⁵² ST I q. 34, a. 2, ad 1. See also ST I q. 27, a. 2, ad 2; q. 29, a. 4; SCG IV 26§7; DP q. 9, a. 9; and In Ioan., #28.

⁵³ Recall n.37 above.

⁵⁴ Quoted from ST I q. 29, a. 3.

⁵⁵ ST I q. 30, a. 1. Thomas argues again from the simplicity of the divine nature, and the subsistence of the divine Word, to the Personhood of that Word in SCG 26§7.

⁵⁶ Trinity, Church, and the Human Person, 82n.44.

⁵⁷ For more on our knowledge of our own intellects and acts of understanding, see Cory, Therese Scarpelli, Aquinas on Human Self-Knowledge (Cambridge: Cambridge University Press, 2013CrossRefGoogle Scholar).

⁵⁸ See, among many others, SCG I, ch. 22.

⁵⁹ It ought to grab our attention that R. L. Richard—who, again, has engaged these questions at far greater length than has anyone else—admits this point quite openly. Towards the beginning of Problem, he asks, “Does Aquinas himself admit the instance where A can be de ratione formali of B, without this de facto truth being evident to merely rational or philosophical analysis? It might well be that the ultimate solution of the verbum dilemma would depend on the answer to that question” (40). Richard continues that “if Aquinas does admit that something can pertain to the ratio formalis of a certain perfection or reality, without unaided reason being able to arrive at the fact relying exclusively on its own resources,” then we could easily square the strength of Thomas's arguments for the Trinity with the limits he places on natural reason. Finally, Richard goes on to argue at length that, in fact, part of the solution to this difficulty lies in holding that natural reason cannot discover some facet of the ratio of understanding (recall n.14 above). Thus, Richard—who, again, has thought about these questions at far greater length and in far greater depth than has anyone else—all but explicitly acknowledges that his solution hinges on claim on which, as we have seen here, all of the members of both of our camps implicitly depend: that natural reason cannot discover some facet of a reality that it encounters among sensible creatures.

⁶⁰ Though we can at least note that a great number of texts—such as ST I q. 12, a. 12: “our natural knowledge can extend as far as it can be led by sensible things”—would suggest that the answer is “no.”

⁶¹ R. L. Richard comes the closest through his analysis of the relation between theology's ordo inventionis and ordo doctrinae. Yet not even Richard ever deals directly with the specific difficulties entailed in the claim that natural reason cannot discover something of the ratio of understanding.