Trinity and Mystery. Three Models for the Contemporary Debate in Analytic Philosophy of Religion

The notion of mystery in the contemporary debate about the Trinity

There is a lively debate in contemporary Analytic Philosophy of Religion (APR) about the issue of whether the Trinity is a logically consistent doctrine or contains such insoluble contradictions that the doctrine cannot be believed. Several positions take part in the debate: Latin Trinitarianism (including Relative Identity Theories) and countless forms of Social Trinitarianism (Tuggy 2016) argue that the Trinity can be satisfactorily explained. Some of these positions also acknowledge the mystery of the doctrine, but in a more superficial than substantial way: their supporters believe to have solved the inconsistency of the dogma (Brown 1985),1 so that “the problem of the Trinity disappears” (Brower and Rea 2005, 69).

On the contrary, those who believe that the Trinity exceeds human rational capacities embrace a position called Mysterianism (MY) (Tuggy 2016). In negative MY it is argued that the Trinitarian theory is unintelligible and that we do not know how to accept Trinitarian analogies, having neither a linguistic formulation nor a useful image that can help us explain the Trinity. In positive MY it is argued that the doctrine is composed of understandable statements that are contradictory when taken together (but this is actually a merit: it is precisely when we solve all the contradictions that we free ourselves from orthodoxy).

I agree with McCall (2010) that the relevance of mystery remains one of the challenges of today’s Trinitarian speculation, but the discussion about the notion of mystery, in the context of APR, seems to remain rather partial and superficial (Wainwright 2009, 80). This is why I plan to analyse three emblematic and much more grounded ways to believe in a mysterious Trinity: Aquinas, Leibniz and Hegel. They all refer to the notion of mystery, but in quite a different sense from the contemporary forms of MY described above, and they represent three emblematic ways of understanding this notion in relation to the Trinity. The positions of Aquinas and Leibniz could be defined as traditional MY: on the one hand, unlike some of our contemporaries, they do not express any certainty about having demonstrated the logical consistency of the Trinity. Hegel proposes a form of positive MY, but he too arrives at a very articulated position with respect to the possibility of believing in the Trinity.

In each of the three cases, I would like to draw the reader’s attention to the fact that any position about the notion of mystery (and about the Trinity) can be grounded only in a coherent metaphysical, linguistic and epistemological system. I would like to show – however briefly – that the notion of mystery is an important feature of the ontologies of these three authors, and not only of their description of God.

Aquinas, for example, relies on the analogical use of language, an approach whose sophistication is underestimated in contemporary discussion. On the contrary, having abandoned analogical language, Leibniz uses ordinary (univocal) language to demonstrate that we do not have a clearly contradictory formulation of the Trinity. His position, however, is rarely considered in the current debate, and deserves to be examined more closely.

Finally, I will recapitulate a few points of Hegel’s thought which, in my opinion, provide a coherent metaphysical frame to positive MY. Hegel is indeed one of the thinkers who have defended the need for contradiction. Hegel, like Leibniz, abandons analogical language but reaches an opposite conclusion and accepts the contradiction of the Trinity as a virtue. However, he can do so precisely because his entire metaphysical system allows it.

Before proceeding, I should mention that my endeavour is neither a historical nor a philological one. My intent is to offer an inevitably broad outline of the doctrines of these three philosophers and to consider their contemporary applications, in order to make their accounts suitable for the contemporary analytic debates. It will not be possible, for reasons of space, to provide an exhaustive historical reconstruction of the debates (documented in the quoted literature) in which these authors took part, or to examine their writings directly. I will approach the authors only using secondary sources, which interpretations will help us to extrapolate “models” inspired by the three authors.

In general terms, Aquinas and Leibniz are committed to disproving the evidence of the contradictoriness of the Trinity, in different ways:

(ε~1~) using analogical terms that inhibit the perception of contradiction;

(ε~2~) lowering the standard for proof (it is sufficient that the thesis be not shown as contradictory);

(ε~3~) limiting the knowability of an object and showing how, in some cases, we have only legitimate knowledge of the object.

These strategies allow us to affirm that, while we have no demonstration of the truth of the doctrine the Trinity, we also have no demonstration of its contradictoriness. This is an essential result in the overall apologetic strategy of the two authors. Hegel’s solution, instead, can be summarized as follows:

(ε~4~) embracing the contradiction.

In summary, the paper aims: a) to present three different conceptualizations of mystery, useful to enrich the debate and to bring new elements of analysis by showing that MY can take many forms; b) to assess a few claims about the logical consistency of the Trinitarian doctrine, and the possible weaknesses of the definitions of mystery based on a distinction between being above and being against reason; c) to underline, in light of the previous point, Hegel’s potential relevance in the contemporary debate; d) to show to what extent the notion of mystery is intrinsic to one’s metaphysics and connected with many epistemological premises, for example analogy and univocity.

Aquinas’ position on Trinity and mystery

In Emery (2007)’s authoritative interpretation, according to Aquinas our reason cannot prove the existence of three Divine Persons (DP). Reason knows God only as the First Cause of creatures and, since creative power belongs to the unity of God’s essence (opera trinitatis ad extra indivisa sunt), we know God to be Pure Act, not a Tri-personal Act (Emery 2007, 23; Porro 2017, 129–130). There are no necessary reasons to postulate the Trinity: Aquinas excludes that it may be the outcome of God’s essential fruitfulness (that had been the thesis of Richard of Saint Victor). God is love, but not in the sense that He loves Himself as human beings love one another: God is love in the sense that He is Perfect Goodness (He wills Himself and this will is Himself). The fact that God is love in the sense of being three DP is manifested through revelation, never proved through reason.

In Aquinas’ account, reason only shows that the claims of faith are not impossible. In the Thomistic model, one arrives to the plurality of Divine Persons by Revelation, and the category of relation is then presented as the most effective means to describe how such plurality is possible (see Coffey 1999). Trinitarian theology has a defensive purpose: Sacra Doctrina does not demonstrate the truths of faith – which are revealed – but defends them from their deniers. It is sufficient to show that the arguments against a dogma are no more than probable (Emery 2007, 29). Our reason can demonstrate the praeambula fidei, but not the truths of faith (Porro 2017, 127–133). The act of believing consists in supposing that divine Revelation is right: dogmas are true ex suppositione and challenge us to argue in favour of their evidence. They are neither evident nor completely explained, but they will become so in the beatific vision. In other words, faith supposes beatific vision because none of the dogmas can ever be proved as contradictory through reason, and it presupposes reason because they must be explored through reason. Some truths of faith are also demonstrable, while others are non-demonstrable. The latter (e.g., the Trinity), however, are also non-refutable, i.e. they will never be proven as contradictory.

Saying that a dogma is true ex suppositione means that we have some independent reason to accept the doctrine of the Trinity (e.g., Revelation): thus, as long as it is not contradictory, we should accept it as true. There is no purely logical proof of the dogma’s inconsistency or consistency: we have other reasons to think that the Trinity is the nature of God and, as long as we cannot prove otherwise, it is within our rights to believe that doctrine.

Non-demonstrable and non-refutable truths, according to a Thomistic-inspired view, belong to the realm of mystery. The process of rational knowledge of God is open to a mystery about which we experience a desire. In the case of the Trinity, we assume the doctrine to be true, and we must show that any alleged proof of its contradictions does not work. Thus, the Trinity is not against reason, but above reason, and therefore a mystery. In this sense, Aquinas’s model differs from the positive MY championed, among others, by Anderson (2007; 2018). According to the latter, we can believe in an apparently contradictory doctrine as long as it is merely apparently – not actually – contradictory (its paradoxical nature is due to our limited cognitive abilities). According to Aquinas, on the contrary, we can believe in a doctrine only when we have refuted any argument that allegedly shows its contradictoriness. I propose to qualify his position as traditional MY, because his way of understanding the mystery is the result and culmination of a traditional understanding of the concept; and because, after him, his position will remain the traditional understanding of mystery for a long time.

How could any alleged proof of the contradictions of Trinity be countered? Aquinas, according to a common interpretation, opts for (ε~2~), i.e. a continuous work of counter-argumentation (Emery 2007, 31). In Aquinas’ thought, however, we also find (ε~1~), i.e. the use of analogy. And it is precisely the use of analogical language that is underestimated in the current trinitarian debate. This use is two-fold:

(ε~1-1~) using notions or terms in an analogical way;

(ε~1-2~) using our imagination to produce images and analogies.

In (ε~1-1~), with regard to the distinction between the DP, what matters is not how the Father is the Father, but the way through which the Father can be the Father of the Son. The speculation on subsistent relations has this (rather limited) purpose: using the category of relation analogically in order to inhibit the awareness of contradiction. In case (ε~1-2~), on the contrary, the Verbum Mentis analogy is the main strategy that allows our reason to imagine how God could be Triune. Therefore, assuming that God exists for sure, and that He has certain characteristics that make Him God (e.g., Simplicity),2 Trinitarian speculation must show:

(α) that the existence of the three DP is not proven to be contradictory;

(β) that the distinction among the DP can be described through:

(β~1~) Trinitarian analogies;

(β~2~) the notions of subsistent relations.

Trinitarian disputes relate to points α and/or β: anti-Trinitarians try to demonstrate the contradictory nature of the propositions concerning the Trinity (against α), or the inadequacy of the categories that allow us to think of 'how' and 'through which' it is possible to express these real distinctions in the divine essence (against β).

It should be underlined that, Aquinas’s confutation of the proof of the contradictions of Trinity does not imply that he gives a consistent account of the latter: analogical discourse allows to express many aspects of the Trinitarian dogma, but not to fully explain it. This position marks a profound difference between Aquinas and contemporary authors (who tend to be overconfident about their logical explanations of the Trinity).

Relationes subsistentes: the difficulty of using analogical terms

About strategy (β~2~), Aquinas introduces a kind of real transcendental relation, where the two relata, being of the same ontological order (which is why the relation is real), are only distinct but not divided (which is why the relation is transcendental). Following his masters, Aquinas draws on the Aristotelian category of relation to clarify the Trinitarian terms (persons and substance) because this category allows him to argue in favour of the existence of real transcendental relations. Aquinas affirms the existence of transcendental relations (e.g. matter-form) and then considers that, in order to be allowed to use the category of relation for the Trinity, only the essence of the category must be maintained, i.e. the fact of referring to something else: Trinitarians relations are transcendental because of this essence, although their relata are not divided. The general ratio (or intelligibility) of the category of relation is therefore maintained (Emery 2007, 94).

Subsequently, Aquinas restricts the meaning of real relation: a relation is real – in a minimal sense – when a relatum proceeds from a principle of the same nature. This is enough to rule out that the DP’s relations are only transcendental. Using the Verbum Mentis analogy, Aquinas reminds us that – in order for the existence of the operations of divine mind to be possible – divine relations cannot be only 'relations of reason (i.e. transcendental), but ‘real relations'. Aquinas transforms real relations into transcendental ones, and transcendental relations into real ones, producing the new notion of 'real transcendental relations' (also called 'subsistent relations') to designate this mysterious reality. We have an analogical concept of a real transcendental relation, even if we do not have an image of it. With this term we can affirm that the relation that really exists in God corresponds to His essence.

Aquinas’ strategy resorts to an analogical predication, arguing that the concept of relation takes on different forms, depending on the ontological level to which it applies. In the process of analogical abstraction, we pass from predicamental relations (i.e. reducible to the properties of the relata) to transcendental ones (whose terms are not divided), up to the relatio subsistens, where the relations become substance. The contradiction intrinsic to the notion of real transcendental relations, therefore, is hidden through analogy.

We should note that the analogical use of 'relation' implies a kind of descending 'hierarchy of relations': there are transcendental relations that belong to the distinctions between divine will and divine intellect, or between divine attributes; real transcendental relations between distinct things (divine persons); real transcendental relations between separate entities (essence-existence); real relations between angels; transcendental relations between separate entities (e.g., soul-body); and real relations between separate entities (e.g., between two bodies). When we say that God is three 'real transcendental relations', this expression is also used by analogy, in the sense that the 'real transcendental relations' of our world are different from the 'real transcendental relations' found in God.

Among Thomists, however, there is no agreement on these relations: some authors find them in specific worldly entities, others consider them to be possible only in God (between DPs), and others still consider them to be contradictory (for a detailed discussion of these positions, see Ventimiglia 1989). The point is that we can accept subsistent relations only if we adopt Aquinas’ analogical understanding of the category of relation (thereby allowing for the existence of real transcendental relations).

Kilby (2005, 2010), for example, advances an apophatic interpretation of Aquinas, trying to show how we can adapt the language in (α) – or the corresponding cases (β~2~) and (ε~1-1~) – to ensure the non-contradictoriness of the propositions, but we do not know what exactly the analogical terms mean. The term 'relation' is emblematic because, for Kilby (2005, 421), it enables non-contradictory language, but Trinitarian relations are not true relations; they are something about which we have neither an image nor a concept. The notion of relatio subsistens erases heresies, but it does not say how the immanent Trinity really is (Kilby 2010, 71).

Kilby concludes that, despite all the theological reflections, God seems to be more incomprehensible than before. This position also claims that no Trinitarian analogy (such as Verbum Mentis, Cerberus, the Statue, etc.) eliminates its contradictions: analogies merely say through images what cannot be formulated through reasoning. By refusing the analogical use of language, but never to the point of declaring that the Trinity is contradictory, Kilby can be associated with negative MY. However, Kilby’s account is a criticism of Aquinas rather than an interpretation of his thought with an emphasis on apophasis.

On the contrary, following Aquinas, White (2016) argues that despite the lack of a worldly example of subsistent relations, as long as this notion is possible, i.e. not inconsistent, it can be a characteristic (one of the 'privileges') of God’s simplicity. We can accept a kind of distinction within God’s simplicity without falling into obvious contradictions, and this is enough to safeguard the doctrine, even if we do not have a clear picture of how this is possible. Simplicity and Trinity concern the nature of God, which we can never completely understand.

This proves that the discrepancies among Aquinas’ interpreters persist and are connected with the wider issues of the analogical use of the category of relation and of accepting analogical language in general (we shall return to this question at the end of the paper).

Analogy in Aquinas’s metaphysics

In Aquinas’ metaphysical thought we find an argument similar to (ε~3~): all entities share a common act of being, but each entity participates in the act of being in proportion to its essence (a substance has more act than an accident). The Pure Act (God) not only has being: it is being, that is, pure existence (limited only by His essence, which is nevertheless perfect and therefore infinite). The problem is that this Pure Act is necessarily present in every entity, but in 'different ways'. We must distinguish between act of being and essence, and say that the Pure Act is in all things, but in an analogical way – a fact that cannot be entirely explained. God is in everything, but no entity is entirely coincident with God, because entities are dependent, while God is independent.

Therefore, entities and God are necessarily separate entities, even if God is completely present in any parts of the entity in the form of their act of being. It is here that the intelligibility of Being keeps alive the mystery of Being itself (Berti 2017, 101–145). There is a difference between the divine act of being (Pure Act) and the created act of being (although the latter is a way of the former). Entities participate in Being, but their being is not Being, even though the Pure Being in Act is necessarily in them. The entities are therefore in the closest proximity to and at the most radical distance from God. We can talk about 'analogy of being' precisely in this sense: entities 'have' or 'are' being to different degrees. This use of analogy is a case of (ε~3~), because analogy implies a degree of equivocity.

Aquinas’ doctrine of Being is partly mysterious also because it is impossible to define whether essence and existence are only principles or actual entities (both solutions present many difficulties, and all Thomists have racked their brains on this question; see Ventimiglia 1989, 416–465; Porro 2016, 183–215). The composition between essence and existence can never be fully explained except through the notion of participation, which refers to that of analogy (Fabro 1960, 1967; Tyn 1991). The essence-existence relation is a real transcendental relation, conceptually similar to a Trinitarian relation. In other words, in order to conceptualize the distinction between essence and existence, we need an analogical use of the concept of relation: a relation whose relata are not completely divided. Thus, even when it comes to worldly entities, explanation seems to go beyond reason, not against reason (thanks to analogical language).3

Again, we can appreciate how the analogical use of language supports and implies an entire metaphysical system (a fact that is widely underestimated by contemporary MY) and how the coherence of the Thomistic system depends on the use of analogy at multiple levels of discourse.

Leibniz’s position

Rationalistic drifts and the non-analogical use of the term person

Leibniz’s Trinitarian thought has been retraced by Antognazza (1996, 207–238; 2002; 2007; I will refer mainly to her interpretation), particularly with regard to his intervention in the “nice and hot dispute” (Dixon 2003) between British Trinitarians and anti-Trinitarians. A broader analysis of this dispute is beyond the goals set in the first section of the present paper. It is sufficient to remember that the rationalist spirit of seventeenth-century Enlightenment and the consequent mistrust in and loss of analogue language (Pérez 2012, 123) revived a kind of anti-Trinitarianism (e.g., Unitarianism and Socinianism) in which the Trinitarian dogma was rejected as irrational or contradictory (Antognazza 2007; Dixon 2003; Lehner 2011). Anglican pastor Stephen Nye (1648–1719),4 for example, claimed that the distinction among DP is slightly greater than the one among divine attributes, but not sufficient to make them into three separate gods.

The dispute involved five positions which are similar to contemporary ones: (a) Ciceronian Trinity (Wallis’s), modalist; (b) Cartesian Trinity (Sherlock’s),5 tritheist; (c) Platonic Trinity (Cudworth and the Cambridge Platonists),6 subordinationist (because based on emanatism); (d) Aristotelian Trinity (South’s), based on the constituent strategy, and adopted by several contemporary authors; and (e) Mysticism, based on accepting the mystery beyond reason.

The seventeenth-century debate mainly focused on the notion of person, which was understood, at the time, in a modern sense that included self-consciousness. Trinitarian discussions re-emerged because, understood in a modern sense, the term 'persons' in the formula 'three persons, one substance' was not understandable: each person in the modern sense can only be a substance with its self-consciousness. Cartesian Trinity coincides with the spreading of cultural awareness which, from Sherlock to German Idealism, Locke and today’s discussion, accentuates the role of consciousness, leading to the maturation of what is today called Social Trinitarianism.

Seventeenth-century anti-trinitarianism also led many authors faithful to the Trinitarian dogma to fideism and biblicism. According to Leibniz, however, if we fail to recognize the difference between being 'above reason' and 'against reason' (in the sense defined earlier by Aquinas), we are forced to choose between fideism (as Bayle did) and rationalism, which eliminates everything that we cannot understand (Antognazza 2002). In fideism (that is a kind of MY) what is against reason is accepted into the faith; in deistic rationalism, dogmas 'above reason' are confused with dogmas 'against reason' and then rejected (Antognazza 2002). Again, it is essential to specify that 'above reason' designates what is not entirely comprehensible but not evidently contradictory.

Given this historical background, it is evident that our current debate is not particularly new. Every contemporary solution has an antecedent in the past. In this specific case, the debate originates from the problems raised by Cartesian Trinity, that is, from a modern conception of the person that no longer takes place through analogical language.

In order to understand the loss of analogical language, let us return to Aquinas for a moment. In his thought, the notion of person is attributed to God in an analogical way and is made to coincide with that of relatio subsistens (RS). Each DP exists for themselves subsistence), in a singular and irreducible way (individuality), with freedom of action due to her essence (intelligence). These are abstract characteristics, but the way in which the DP are persons remains incomprehensible to us, since it is infinitely different from how humans are persons (Emery 2007, 108). The term 'person', applied analogically to God, indicates only self-subsistence, incommunicability and intellectual nature. The divine substance is the Pure Act: as Pure Existence, it can encompass (in a way unknown to us) the presence of three subsistences. RS are called Persons because the subsistences have the minimum characteristics of a person (Emery 2007, 120).

'Person' does not have a broader conceptual extension than RS: it has no psychological connotation (or only an indirect one, derived from God’s intelligence and will). Every reference to the modern connotation of the term 'person' is lost. In Aquinas, the terms 'substance', 'rationality', 'relation' and 'person' are all understood in an analogical sense.

Leibniz addresses the aporias raised by the Trinity by showing how the latter is above but not against reason, without however resorting to the analogical use of the term person. Leibniz defines a person as a substance that is single in number and incommunicable: it is a substance in the sense that it is subsistent and not accidental; single in the sense that it is individual; and incommunicable in the sense that its properties are non-transferable. Thus defined, each DP is rational (by essence) and substantial, but exists only in relation to the others.

Leibniz clearly states that the DP are only ways of subsistence, but they are also substantial subsistents (Antognazza 2007, 158). Therefore, something more than a reference to the relations is needed. However, Leibniz is also aware that the aforementioned sparse definition of person is the only one that can escape the pitfall of tritheism. The term person cannot be applied to DP in the modern Cartesian way, lest the DP become three gods (Antognazza 2007, 154). However, we will see that the term substance, in Leibniz, presents several ambiguities.

Leibniz’s Relative Identity strategy

Leibniz claims that mysteries of faith cannot violate the principle of non-contradiction (PNC), but are above reason. In Antognazza (2007)’s interpretation, therefore, Leibniz starts from the presupposition of truth (PT): following (ε~2~), it is initially assumed and subsequently maintained that a mystery is true; opponents have the onus probandi, since they must show that the contradictoriness is evident. If they fail, the mystery remains possible and therefore believable.

With respect to the strategy used to show that the (Cartesian) Trinity is not contradictory – that is (α), or (ε~2~) – Leibniz formulates an argument (Antognazza 2007, 153) similar to the one currently proposed by the supporters of the Relative Identity Theory (RIT), upon which I cannot dwell due to a matter of space. In short, it consists in interpreting the verb 'to be' in a different way in the expressions 'being God' and 'being the Father' (ibid., 72): in the first case God is considered absolutely, in the second relatively. Relative identity is based precisely on the application of different sortals (substance and person) to two subjects, showing that they can be identical in one respect, but not in another: God-identical but Person-distinct (Rea 2003, 432) or, in Leibnizian terms, God taken absolutely and God taken relatively. The essential problem of every solution based on RIT lies precisely in the distinction between substance and person: it is no longer possible to say what this substance can be, since, presumably, the absolute substance is such because it is already all the intra-Trinitarian relations, which therefore should be communicated to each of the three DP. This is why the Leibnizian definition of a person described above is of little use.

If we accept the equivalence between Leibniz’s 'RIT argument' and that of contemporary authors, we can propose a few brief (and of course not exhaustive) considerations about its effectiveness: RIT is quite a controversial theory, both philosophically (Varzi 2008, 141–156; Giaretta and Spolaore 2008, 141–156) and theologically speaking, because it does not describe an orthodox Trinity. This means that the distinction, introduced in RIT, between the verb 'to be' as a 'verb of predication' and as a 'verb of identity' does not help us solve the problem of the Trinity. It allows us to preserve a non-contradictory linguistic formulation of the dogma, but it fails when the terms in the formulation are disambiguated.

Thus, we may have solved the so-called 'logical problem' (Cartwright 1987, 187–200) but the doctrine that emerges from RIT’s linguistic turn is at best heterodox. When 'a God' is predicated of a DP, 'God' already means 'a DP' (the way of being God that implies unity in the distinction); otherwise the predication is 'classical' (it means God), in which case we have a form of tritheism. Cartwright (1987) underlines that Trinitarian theologians find themselves back where they started: trapped between not confusing the DP and not dividing the substance.

Bertini concludes about RIT: “The fact that this formulation has no problems of consistency does not mean that the doctrine of the Trinity is not contradictory, but simply that the contradiction does not necessarily emerge […] from the simultaneous predication of divinity and personality” (Bertini 2009; 2015). However, as soon as the terms divinity, person and substance are clarified, the contradiction re-emerges, and we are back to (β~2~), i.e. to postulating new kinds of entities or subsistent relations. The discussion on RIT shows that logic can be adapted to our metaphysics, our science, and the needs of our discourse; but logical formulations do not necessarily correspond to something in reality, and this exposes a discrepancy between epistemology and ontology.

Leibniz and contemporary RIT supporters propose a linguistic solution, but they fail to explain β~2~. RIT is part of a strategy that consists in showing that there is a consistent language regarding the Trinity and that this language can be used. According to Bertini (2009), in order to affirm the orthodox doctrine we must defend in a robust sense both the divine unity and triplicity. Every other weak interpretation – although more desirable rationally – is not in agreement with the dogma. RIT does not describe an orthodox Trinity or, if it does, we have fallen back into (ε~1~), i.e. we are in need of analogical terms (such as relatio subsistens).

The notion of mystery in Leibniz: kinds of knowledge

In a second strategy (ε~3~), Leibniz shows that something similar to the Trinitarian argumentation can be found in the description of other phenomena (e.g., substances) (Antognazza 2007, 15–25). Strategy (ε~3~) involves the belief that we can legitimately have a confused knowledge of a mystery that cannot be proved contradictory. In Leibniz’s scheme, knowledge can be obscure, if it does not allow us to identify a certain content; clear, if it does; confused, if it cannot be sufficiently analysed (or if its various components cannot be properly isolated); distinct, if we can identify a sufficient number of elements; adequate, if the elements are exhaustive; and perfect, if it is clear, distinct and adequate (such is the knowledge of God).

Contra Descartes and Locke, Leibniz argues that human knowledge is not limited to what is clear and distinct. The clarity of knowledge is linked to the knowability of the object, and our knowledge can be not totally clear about several notions such as substance, nature, persons, etc. This kind of knowledge is not against reason, because knowledge is something more than comprehension (Antognazza 2002). There is a parallel between a certain unknowability of the world (as in the monads) and the unknowability of God. How individual substances are in their inner nature is as unknown to us as is the nature of God.

In Leibniz’s scheme there is no distinct knowledge about the Trinity. Leibniz reiterates, however, that we cannot have a complete notion of substance, just as we cannot have a complete notion of the Trinity: there are, also in our world, entities whose understanding is beyond reason (that is, they lack distinctiveness). Therefore, understanding is a mix of clarity, distinction and adequacy, which varies according to the object to which it applies: in the case of a primitive term (that is, a term achieved through phenomenological reduction), adequacy standards are very low. There are different degrees of knowledge (Antognazza 2007, 127–128) and, even when our knowledge is not distinct, it could still be adequate. We can see a tension in the use of the adjective 'adequate'. If there is a degree of adequacy, then a knowledge that can not be totally clear is in a certain sense adequate to some objects. To avoid this ambiguity, I propose to define (as a hypothesis) this kind of knowledge – for simplicity of reference – as legitimate knowledge.

To sum up, Leibniz’s thesis is that God can be considered as Triune (clarity), even if we do not know how He is so (distinctiveness). We only know that God can (although Leibniz’s argumentation seems to imply that God must) be One and can (must) be Triune, even if the mode of composition of these two truths remains precluded to us (ibid., 8). At this stage, we can associate Leibniz, at least partially, with negative MY.

It seems to me that (ε~3~) is peculiar to Leibniz’s thought (even if, as we have seen, Aquinas also admits a 'mystery of Being'). By resorting to (ε~3~), Leibniz limits the knowability of an object, showing that in some cases we can only have – if we accept my terminological proposal – a legitimate knowledge of it. In the future, it could be interesting to investigate if legitimate knowledge is what we achieve through analogical reasoning. But first, let’s see how the mystery is present in Leibniz’s ontology.

Mystery in monadism and other analogies

Could Leibniz’s monadism serve as a model for Trinitarian relations? In the more mature developments of Leibniz’s ontology, according to Antognazza, monads are simple substances without parts,7 but they have a plurality of affections. Monads are spiritual, and their inner intellectual acts are distinct. There is, however, a difference between the multitude of affections in the monad and the one in composed substances. The former multitude distinguishes but does not divide (multitude without separability) (Antognazza 2007, 29):8 the fundamental reality of the world is an infinite number of monads with infinite distinctions inside them. This multitude is similar to the Trinity’s plurality of persons (ibid., 110). However, the existence of this multiplicity depends on our willingness to accept a real distinction between the affections of the monads and the existence of spiritual entities with inner distinctions (perceptions) that are not really divided.

It is interesting to note that we can find something comparable to the monad’s inner distinctions also in Aquinas’ distinction between existence and essence: entities (a pile of wheat, an individual, the soul, God, etc.) all have a different degrees of unity, while also implementing the transcendental unum. Similarly, to the inner affections of the monads, every entity in Aquinas’ account has an inner composition or inner plurality. The 'composition' between essence and existence is the most similar to the composition among the persons of the Trinity (composition in the absolute divine simplicity), because it is a real transcendental relation. If this is true, then the notion of Being is mysterious in both Leibniz and Aquinas. Both authors assume a correspondence between the mystery of fundamental beings and the mystery of God. In the case of Leibniz, the plurality of the monads and their affections has the same mysterious nature as the plurality of the DP.

An issue less explored in the literature is Leibniz’s idea that there must be plurality in order to achieve harmony, since the latter is only possible as unitas plurimorum or diversitas identitate compensate (Antognazza 2007, 21 and 168): therefore, if God is harmony, He is also unity in plurality. This would be an effective proof of the Trinity. According to Leibniz, the Trinity is the perfect achievement of the idea of ​​harmony (Antognazza 2007, 22). Just as the world is a concrete and complex system, so too the Trinity is a system composed of DP.

Process Trinitarians (Boyd 1992; Bracken and Suchocki 1997) – who perform a synthesis of the insights of process metaphysics and trinitarian speculation – accept the analogy of harmony in different forms because in process metaphysics, entities are societies of actual occasions, similar to Leibniz’s monads (Rescher 1996). Not only is the universe composed of many entities in harmony, but every entity is, in a way, an infinite plurality of occasions. God is the highest metaphysical exemplification of the way in which the universe ontologically is.

However, Leibniz’s argument can be weakened if we consider that every substance has the transcendental of unity (oneness), and its First Cause is a Simple One God. The universe is composed of a plurality of entities, but each of them has the transcendental of unity, so that God must only exemplify this transcendental. Moreover, if it is true that process metaphysics is the heir of monadism (Seibt 2018), process trinitarianism could suffer from the same aporias found in process metaphysics (see Pugliese 2011; Weeks 2004).

According to Powell (2001, 52), Leibniz adds two analogies for (β~1~): one derives from his concept of substance, the other from the reflexivity of the self (God is a process of self-knowledge). Let us start with the first: according to Leibniz, the Trinity is an emblematic example of substance, understood as force. Every entity has force, that is, appetite and perception. It is a monad, or at least an aggregate of monads, and monads are the best concept of substance that we can have (mysterious, but not contradictory). Monads have perception of the external world and therefore have distinctions, but no internal divisions. If this is true, then force, perception, and appetite exist in God in an eminent way as supreme and infinite substance-forces. If God is Triune, He will be like the earthly substances (monads), but infinite: the DP are the three aspects of substance. In other words, they are three distinctions. Perception-knowledge is the second Person (wisdom), and appetite-will the third (love).

Thus, we reach the analogy of reflexivity. If the mind exists, Leibniz claims, there must be real distinctions between the thinking subject, the act of thinking and the thought itself. Due to the existence of these distinctions, there must be in God a plurality which corresponds to the DP (Powell 2001, 28). The mind that thinks of itself and has self-consciousness elicits a diversity inside itself (ibid., 30). Again, however, the use of analogies is controversial: every analogy – as we have seen, from the point of view of a negative MY – partially deforms the truth of the Trinitarian dogma. Analogies merely say through images what cannot be formulated through reasoning.

Leibniz’s ontology of relation and the Trinity

Leibniz’s anti-Sabellian position is also partly favoured by his ontology of relation (Mugnai 2001b, 85–96): Leibniz is a conceptualist about relations, i.e. he reduces them to the properties of the terms (correlatives). The DP are also correlatives (subsistens relativum), i.e. they are relative substances rather than subsistent relations. This position pushes him towards a sort of 'pluri-substantialism' (Erismann 2008), although the harmony and metaphysical dependence among these 'substances' can ensure their unity in a single substance (Antognazza 2007, 107 and 157–160). Leibniz’s proposal involves three substances in relation (substances 'taken relatively'), one absolute substance that contains them all, and the same individual nature communicated to all (substance 'taken absolutely'). There are three relative beings in the same absolute being (ibid., 107), but they are not parts of this being, since none of them can exist separately from the others and because each being expresses the totality of the divine essence.

On the epistemological level, Leibniz admits that there is no example in nature similar to this situation (only the human spirit and the monads offer some analogy). However, he believes that we do not need to find such an example, because what matters is the absence of contradiction; having established this, Leibniz concludes, nothing prevents us from thinking that God has a kind of 'privilege' about the way of being a substance.

As Antognazza points out, however, Leibniz’s use of 'substance' is ambiguous. Depending on how the propositions are interpreted, his speculation is either tritheist or modalist: this weakness, highlighted above with respect to the solutions based on RIT, regards the delicate transition from (α) to (β). In order to remain between the two outcomes, Leibniz can no longer say what this substance can be – or what the three correlatives are – given that the absolute substance is a kind of substance that already includes the Trinitarian relations. All these relations should be communicated to each of the DP through their common substance. It seems that when the term is used univocally we inevitably fall into tritheism.

An anti-apologetic argument?

In order to better understand the importance of Hegel’s perspective, we first need to ask if the 'argument ex suppositione' – used in different ways by Aquinas and Leibniz – is effective. Such a doubt is somewhat justified: if there is no proof that the Trinity is consistent, it can be assumed that it is contradictory. In other words, one could say that believing in the Trinity amounts to believing in a contradiction. This is what we would call an 'anti-apologetic argument'.

In other words, an anti-Trinitarian could show that arguments against the contradictoriness of the Trinity are not conclusive (a strategy used by Bayle; see Wainwright 2009, 86). At this point, however, both Trinitarians and anti-Trinitarians base their argument on a truth ex suppositione, and both are justified in believing in their truth. The crucial question, therefore, is if we really do have a proof of the contradictoriness of the Trinity.

Despite the lack of consensus, today the idea that the Trinity is contradictory is gaining appeal (see Beall 2021, 152–175). Even without a proof, the most compelling 'anti-apologetic argument' may be that, in contemporary APR, there are many alternative accounts of the Trinity, each accusing the others of being contradictory (at worst) or unorthodox (at best). The last charge is particularly interesting: in their attempt to solve the contradictions of the doctrine, contemporary authors accuse one another other of offering heretical accounts of the Trinity. So, if there are indeed logical ways to formulate the doctrine, they lead to forms of heresy (modalism, tritheism, subordinationism, etc.). This fact – it is not properly an 'argument' – could raise the suspicion that the problem lies precisely in the claim that the Trinity can be logically expressed.

In this light, perhaps, the role of the dogma is precisely to affirm what it must be believed by means of antinomic propositions, against all rationalist simplifications. Of course, theological reasoning tries to avoid the perception of contradictions: we have seen that Trinitarian speculation invents specific terms – such as subsistent relation, as in the case of (β~2~) – to name what rationally escapes us, or it produces analogies, as in the case of (β~1~). The role of theological reason, here, is to make it possible for a believer to belong to a faith without needing to explain it completely. But the disagreements among Trinitarians about the logical formulation of the doctrine could show, even if indirectly, its contradictory nature.

We have seen that the strategies proposed by Aquinas (based on the analogical use of the category of relations) present a few difficulties and probably fail to dispel the contradictions. At the same time, Leibniz’s argument, based on RIT, does not work any better (it seems to return to Aquinas’ position, but not using analogical language). The contradictory nature of the Trinity therefore remains an open question. Let us assume, however, that its logical inconsistency is demonstrated or that the anti-apologetic argument works. Does this mean that the doctrine is hopeless? It is at this stage that Hegel can come to our help.

Hegel’s position

The Trinity as a representation of the life of the Spirit

According to Hegel the Trinity is the religious representation of a truth of reason concerning the Absolute Spirit (Illetterati et al. 2010, 313).9 Religion and philosophy express the same truth, but in different forms: the first uses representations, while the second uses concepts. Representations are metaphors of concepts, that is images that have been universalized but not yet expressed in the form of thought, which is precisely the concept. Representation is a «universal determination expressed through perceptible elements» (ibid., 112). The concept, on the other hand, is a form of rational understanding, it is life, movement, a synthesis of universality and particularity (ibid., 165).

In a narrative, the Christian Trinitarian event – the Father who alienates himself in the Son, becomes human, and then returns to himself – represents the life of the Absolute Spirit which, from universal and infinite, becomes concrete and finite. This truth of the reality and of the Spirit, its movement and life, however, cannot be grasped by the intellect (Verstand) alone, but by reason (Vernunft), because the former separates, while the latter finds the unity of the concept (Begriff).

The intellect fixes the concepts rigidly, while reason understands the movement of the concept of the speculative proposition (Verene 2007, 8–10): «If the reflection of the intellect, separating the part from the whole, simply poses the oppositions and thus produces the scissions, the reflection of reason, denying the isolation and rigidity of these oppositions, removes them from their unrelated subsistence and considers them together, in their unity» (Illetterati et al., 2010, 50). Only reason, therefore, is able to grasp the dynamics of the life of the Spirit and express it in the dynamics of the movement of the concept, which is precisely the dynamic synthesis of oppositions.

The intellect separates entities and distinguishes them (in this sense it is 'analytical'), while reason produces a synthesis that overcomes these distinctions. Reason understands that every finite is precisely 'finite', a part of the Whole, but that at the same time it is a relation with the Whole: it is the Whole, it is infinite. Each finite is the truth of the Spirit, but the complete truth is in the Whole. In order to grasp the nature of things and of the Spirit (of Infinity), therefore, one must go beyond the intellect and think about the contradiction. In order to understand the rationality of reality, its dynamism, the coexistence of the finite and the infinite, the universal and the particular, we need «an uncontradictory assumption of contradiction» (ibid., 121). But only reason knows the intrinsic relationship that connects each part and the Whole: the intellect limits itself to separating the parts, fixing them instead of grasping them in their becoming and dynamism; the intellect generates contradictions which reason manages to sublate.

Of course, it is not easy to interpret the extent to which Hegel accepts the contradiction as a part of his system (Illetterati et al. 2010, 117 and 160). However, I believe that Hegel’s system rests on the assumption that, in some cases, the PNC (Principle of Non-Contradiction) becomes irrelevant because it is an instrument of the intellect and not of reason. According to Hegel, we can accept the contradiction by including it into a kind of 'reason' that is more powerful than the intellect.

If the Trinity is a representation of the Spirit and, therefore, of the whole reality of the world (insofar as the world is the Spirit in its manifestation), it must be expressed in philosophical terms, that is through the movement of a concept that is produced by reason. This means that the Trinity, just like the Spirit, must pass through the abyss of contradiction. In this sense, the Trinity is mysterious to the intellect, but not to reason: reason can achieve the conceptualization, the synthesis beyond negation, distinction and contradiction, in the sublation (Aufheben) (Maybee 2016). Reason can grasp the Trinity, recognizing it as the summit of its own speculative itinerary.

Spirit, contradictions and the Trinity

In the Hegelian system, the universal (the Spirit) self-denies and becomes particular (the world). God is Spirit and follows the rules of the concept, which makes itself Universal, Particular, and Individual. These are three ways of God’s being: God is a concept which differentiates itself, He is one and many. Therefore, according to Hegel, the Trinity is known by reason as the logic of the Spirit, as a representation of the Spirit’s logic of negation, differentiation and reconciliation. 'Universality-Particularity-Singularity' are separate terms only to the intellect, but reason is able to hold them together, in a synthesis beyond contradiction (Illetterati et al. 2010, 167). From a philosophical point of view, the Spirit is a synthesis (beyond the contradiction) of One-Many, and the Trinity is the religious representation of this synthesis.

The One God is the anthropomorphic God of the intellect, the Triune God (the Spirit) is the God of reason. Being grasped by reason, the existence of contradictions in the Trinitarian doctrine is certainly not a demerit, in Hegel’s account, but a sign of the doctrine’s virtue (Powell 2001, 104–141). Reason sublates the moment of the contradiction of the One-Many by re-understanding it in light of the Trinitarian God. Hegel’s strategy to defend the Trinity is therefore (ε~4~), embracing the contradiction, thanks to a use of reason that tolerates contradiction as its speculative moment. Hegel’s Spirit is becoming, a dialectic game of being and nothing: a differentiation constantly in the act of being achieved (and sublated). Hegel’s God is, ab aeterno, «self-identity, self-differentiation, and self-return», and «the Trinity is true because it is a representation of God’s essence» (Bubbio 2014, 139). The Trinity as synthesis of the contradictions is the only solution to the One-Many problem, that is, the explanation of how the One can become the Many of the world. In this case, too, the difference between Hegel’s and Anderson’s position (see above) is clear. In the former, the contradictions are not 'merely apparent', but real. Even if sublated in a higher synthesis, they are never completely 'removed'.

Hegel and the Analytic Philosophy of Religion: a complicated relationship

From Hegel’s perspective, contemporary APR could probably be defined as an illusion of the intellect. It is the intellect that produces antinomies, that is, all the irreconcilable positions that we find within APR itself (this may be the cause of the competing positions on the Trinity that give rise to the anti-apologetic argument). This illusion must be overcome through reason: Hegelian dialectic theology is antithetic to APR because in this dialectics the PNC is only a partial instrument, insofar as it is an instrument of the intellect but not of reason. Kant showed that our metaphysical reasoning about reality (and God) is antinomic, and that we do not have to represent either side of the antinomy as true. Hegel picks up Kant’s intuition but argues that we must bring these sides together in a synthesis that goes beyond their contradiction. The Trinity is a philosophical achievement because it is coherent with the truth of the Whole: it is a synthesis of stasis and movement, Unity and Multiplicity, Being and Becoming. But this necessary and supra-intellectual reconciliation is reached through reason, not through fideistic intuition.

Something similar to Hegel’s position can be found, today, in the so-called dialetheism (see Priest and Berto 2017), even though the association of the Hegelian system to a form of dialetheism remains debatable (see Mancini and Carrara 2021). Dialetheism, which affirms that there are true contradictions, has recently been applied to the Trinity (see Beall 2021; for a historical precedent: see Lourié 2018). In this perspective, the claim that «different entities all of whom are identical to a unique being (viz., God) is fully achieved only via contradiction, and anything less than contradiction yields less than full identity and difference – an identity without a difference, so to speak, or a difference without identity» (Beall 2021, 175). Therefore, «a contradictory theory can be rationally chosen because its contradictory character is counterbalanced by other criteria» (Mancini and Carrara 2021, 56). This is a difficult conclusion to accept for tenants of the APR. But it is, at least, a reasonable perspective (as long as paraconsistent logic is accepted) and a legitimate way of understanding the Trinitarian mystery.

Conclusion: can we choose a model?

In light of our analysis, we can say that, if the claim – sometimes implicitly advanced by contemporary authors – to have solved the logical problem of the Trinity is at least doubtful, this does not mean that we must adhere to negative MY or positive MY: the alternative offered by Aquinas and Leibniz are different versions of what we called traditional MY. Moreover, even if the Trinitarian doctrine is contradictory, one can still adhere to MY at least in the Hegelian sense.

Aquinas and Leibniz refuse to accept the contradiction but admit that there is something above reason that we cannot express (although God could do so, ex suppositione). Aquinas believes that we can talk about what lies beyond our reason through analogical language and analogies. Leibniz uses linguistic strategies in order to achieve a legitimate knowledge. In Hegel, on the contrary, the contradiction is accepted and reconciled into a higher level.

We have seen that their solutions are not fully equivalent to today’s positive or negative MY. However, if we admit that the positions of Aquinas, Leibniz and Hegel are more grounded and complete than those of contemporary authors, which model should they choose? We have seen that there is no conclusive argument to accept or refute Aquinas, Leibniz and Hegel. What we can probably gain at this point is just a greater awareness of the implications of their positions.

In order to adopt Aquinas’ position on mystery, one should embrace his analogical use of terms in ontology and in theology. This is quite uncomfortable for contemporary analytic authors, who view analogy with some suspicion. In his book on the Trinity, Hasker observes that trinitarian language seems to require to abandon the strong professional bias that impels analytic philosophers to make language really precise and to construct tight formal arguments; but, at the same time, he claims that «with analogical language […] there is often a degree of ambiguity or vagueness concerning the intended meaning» (Hasker 2013, 171, italics added).

Hasker – whose position, in my view, is close to Leibniz’s – here highlights the problem that we left open in the last paragraph. Analytic philosophers of religion seem unable to solve the Trinitarian dilemmas (as Hasker clearly points out).10 This impasse appears to emerge in several APR discussions on religious and ontological topics. Although I cannot dwell on this point, a few perspectives for future speculation can be drawn from Hasker’s claims.

Hasker emphasizes that analogical sensitivity, or analogical tension, has been lost in APR (and, we could add, in ontology). Of course, Hasker’s view could be challenged by the fact that, in the analytic field – admitting that there is a common way to define it – we find the so-called Analytic Thomists. This fact raises the question of whether there should be anything about the nature of analytic philosophy that would not allow analytic philosophers to accept the analogical strategy.

However, many contemporary analytic philosophers share the belief that analogy is both powerful and weak: its intrinsic indeterminacy makes it immune to objections, but every analogical use of a term lends itself to equivocity. The problem, here, is to establish whether the analogical use of terms is imprecise (and, if so, whether an analytical use would indeed work better). Kilby’s approach is an example of this questioning, which in some sense dates back to Ockham (Ghisalberti 1972, 98–120). Indeterminacy is what leads many contemporary analytic authors to avoid the analogical use of terms.

In any case, Hasker seems to claim that the linguistic turn of analytic philosophy and the obsessive search for lexical precision, did not enable a simplification of the problems or new solutions. On the contrary, it seems to have led to a multiplication of metaphysics and ontologies (see also Tripodi 2015). This may at least partly justify the claim that it is precisely the analytic approach that leads to dialectical results, that is, to the possibility of alternative, opposite, and logically defensible metaphysics and ontologies. The same conclusion could be drawn with regard to the specific case of APR, where the analytic approach to religious topics has multiplied the (opposing) options and solutions.

All things considered, there may be a correlation between univocity, analyticity and the dialectical outcome of many APR discussions, but this point needs to be further investigated in order to uncover the underlying causes that lead analytic philosophy to the symptom described by Hasker. Clearly, the problem of establishing the difference between ontologies, metaphysics and theologies based on analogy or univocity is too wide (Varzi 2019, 355–384) – and the relevant body of literature too extensive – to be addressed here.11 As Micheletti (2018) rightly argued, the analogy-univocity issue is an intellectual challenge for the future, which we can only leave here as an open question.

Going back to the issue of choosing a model, in order to adopt Leibniz’s position on mystery one should embrace RIT, but this strategy is very controversial. He seems unable to avoid the problems that follow from a model in which God is described as a Person in a univocal and modern sense. Moreover, RIT seems to produce a heterodox doctrine. Finally, if we accept that the strategies of Aquinas and Leibniz aim to hide the contradictoriness of the Trinity, but that they fail in this endeavour, we may need to embrace Hegel’s position in order to escape the anti-apologetic argument.

Today, Hegel’s theology is described as dialectical, but he would probably describe it as a kind of natural theology, where our natural faculty of understanding is 'reason', as opposed to the 'intellect'. Even if most tenants of contemporary APR consider Hegel’s 'reason' as nothing more than nonsense, I believe that positive MY could be very similar to Hegel’s account, insofar as both accept that the strength of the doctrine lies in its intrinsic contradiction. In Hegel, the doctrine is accepted through a rational process, precise metaphysics and strong epistemological awareness, all qualities that positive MY is still lacking but which it could acquire. Again, we can see how a thinker’s entire metaphysical system is essential to determine what is a mystery and what can be believed.

Of course, we can ask ourselves whether the positions of Aquinas, Leibniz and Hegel are actually opposed. Despite their differences, these three classical positions agree that rational discourse needs to go beyond the plane of analytical intellect. This is perhaps the most challenging (and compelling) contributions that these three thinkers can bring to our current debate. In Aquinas, human reason, whose powers of understanding are limited, allows us only to embrace a bit of the divine reason (whose powers of understanding are unlimited) through analogical language. Leibniz prefers to introduce what I have called legitimate knowledge. Hegel’s reason understands the life of the Spirit beyond the intellect, leading to a synthesis of contradictions. Perhaps Hegel’ and Aquinas’ positions are not so opposed, since both assume that reason is split in two (human reason/divine reason and intellect/reason respectively). The split is merely expressed in two different ways, namely through dialectical and analogical language. What in Hegel is beyond the intellect, leading to synthesis of the contradictions through reason, in Aquinas is beyond reason (therefore expressible only through analogy). Of course, the two are separated by their different stance on the acceptance of contradiction, an abyss which may be partially filled by the development of a paraconsistent logic that broadens the spectrum of what human reason can believe.

It is worth considering that contemporary discussions on evidentialism (Swinburne 1997, 681–687) argue that beliefs can be justified even in the absence of evidence. However, it seems difficult to accept that reasonable argumentative and cognitive premises may lead to contradictory conclusions (beliefs). This is de facto an anti-Trinitarian objection: if the notion of the Trinity is inconsistent, the belief is false. In the Hegelian system this problem is solved: we can still believe in something that is not only above, but also against reason, provided that the Trinity is against the intellect but not against reason. We can be mysterianists at least in this sense. Contemporary dialetheism helps us in this path, but we have also seen the importance of developing comprehensive metaphysics and epistemology. Maybe, those who are satisfied neither with the analogical solution of classical metaphysics nor with the univocal solution of process metaphysics, or Hegel’s idealism, can follow a third path: a kind of negative ontology that recognizes the impossibility of avoiding apophatism even when dealing with fundamental ontology (Migliorini 2018). But, again, these are the subjects for future investigations.


  • Anderson, James 2007. Paradox in Christian Theology. Eugene: Wipf and Stock.
  • Anderson, James 2018. “On the Rationality of Positive Mysterianism”. International Journal of Philosophy of Religion 83, 291–307.
  • Antognazza, Maria Rosa 1996. “Leibniz e il concetto di persona nelle polemiche trinitarie inglesi”. In: L’idea di persona. Edited by Virgilio Melchiorre, Milan: Vita&Pensiero, 207–238.
  • Antognazza, Maria Rosa 2002. “Leibniz, Gottfried Wilhelm (1646–1716)”. Dizionario Interdisciplinare di Scienza e Fede.
  • Antognazza, Maria Rosa 2007. Leibniz on the Trinity and the Incarnation. New Haven, CT: Yale University Press.
  • Beall, JC 2021. The Contradictory Christ. Oxford: Oxford University Press.
  • Berti, Enrico 2017. Introduzione alla metafisica. Turin: Utet.
  • Bertini, Daniele 2009. “Che cosa non va nel modalismo?” Reportata.
  • Bertini, Daniele 2015. “Against Trinitarian Enthusiasm”. Reportata.
  • Boyd, Gregory 1992. Trinity and Process. New York: Peter Lang.
  • Bracken, Joseph, Marjorie H. Suchocki 1997. Trinity in Process. London: Continuum.
  • Brower, Jeffrey and Michael Rea 2005. “Material Constitution and the Trinity”. Faith and Philosophy 22, 57–76.
  • Brown, David 1985. The Divine Trinity. London: Duckworth.
  • Bubbio, Paolo 2014. “Hegel, the Trinity, and the 'I'”. International Journal for Philosophy of Religion 76, 129–150.
  • Cartwright, Richard 1987. “On the Logical Problem of the Trinity”. In: Philosophical Essays. Edited by Richard Cartwright, Cambridge, Mass.: MIT Press, 187–200.
  • Coffey, David 1999. Deus Trinitas. Oxford: Oxford University Press.
  • Dixon, Philip 2003. Nice and Hot Disputes: the Doctrine of the Trinity in the Seventeenth Century. London: T&T Clark.
  • Emery, Gilles 2007. The Trinitarian Theology of Saint Thomas Aquinas. Oxford: Oxford University Press.
  • Erismann, Christophe 2008. “The Trinity, Universals, and Particular Substances: Philoponus and Roscelin”. Traditio 63, 277–305.
  • Fabro, Cornelio 1960. Partecipazione e Causalità in San Tommaso d’Aquino. Turin: SEI.
  • Fabro, Cornelio 1967. “Participation”. In New Catholic Encyclopedia.
  • Ghisalberti, Alessandro 1972. Guglielmo di Ockham. Milan: Vita&Pensiero.
  • Giaretta, Pierdaniele, and Giuseppe Spolaore 2008. Esistenza e Identità. Milan: Mimesis.
  • Griffiths, Gwyn 1996. Triads and Trinity. Cardiff: University of Wales Press.
  • Gunton, Colin 1991. The Promise of Trinitarian Theology. Edinburgh: T&T. Clark.
  • Hasker, William 2013. Metaphysics and the Tri-Personal God. Oxford: Oxford University Press.
  • Illetterati, Luca, Paolo Giuspoli, and Gianluca Mendola 2010. Hegel. Rome: Carocci.
  • Kilby, Karen 2005. “Aquinas, the Trinity and the Limits of Understanding”. International Journal of Systematic Theology 7, 414–427.
  • Kilby, Karen 2010. “Is an Apophatic Trinitarianism Possible?” International Journal of Systematic Theology 12, 65–77.
  • Lehner, Ulrich 2011. “The Trinity in the Early Modern Era (c.1550–1770)”. In: Oxford Handbook of the Trinity. Edited by Gilles Emery and Matthew Levering, Oxford: Oxford University Press, 240–253.
  • Loeschen, John 1971. “The God Who Becomes: Eckhart on Divine Relativity”. The Thomist 35, 405–422.
  • Lourié, Basil 2018. “A Logical Scheme and Paraconsistent Topological Separation in Byzantium”. In: Relations. Edited by Daniele Bertini and Damiano Migliorini, Verona: Mimesis International, 283–299.
  • Mancinelli, Paola 2009. “La Croce nel concetto: rileggere Hegel alla luce della teologia trinitaria”. Reportata.
  • Mancini, Filippo, Massimiliano Carrara 2021. Sul dialeteismo. Lezioni padovane di Graham Priest ed altri saggi sul dialeteismo. Padova: Padova University Press.
  • Maybee, Julie 2016. “Hegel’s Dialectics”. Stanford Encyclopedia of Philosophy.
  • McCall, Thomas 2010. Which Trinity? Whose Monotheism? Philosophical and Systematic Theologians on the Metaphysics of the Trinity. Grand Rapids: Eerdmans.
  • Micheletti, Mario 2018. “Radical Divine Alterity and the God-World Relationship”. In: Relations. Edited by Daniele Bertini and Damiano Migliorini, Verona: Mimesis International, 157–170.
  • Migliorini, Damiano 2018. “Troubles with Trinitarian (Relational) Theism: Trinity and Gunk”. In: Relations. Edited by Daniele Bertini and Damiano Migliorini, Verona: Mimesis International, 181–200.
  • Migliorini, Damiano 2019. “Ten Strategies for the Trinity”. Nuovo Giornale di Filosofia della Religione.
  • Monaco, Davide 2010. Deus Trinitas. Dio come non altro nel pensiero di Nicolò Cusano. Roma: Città Nuova.
  • Mugnai, Massimo 2001a. Introduzione a Leibniz. Turin: Einaudi.
  • Mugnai, Massimo 2001b. Leibniz’s Theory of Relations. Leibniziana supplement. Stuttgart: Franz Steiner.
  • Mura, Gaspare 2009. “La Trinità in S. Tommaso e in Hegel”. Reportata.
  • O’Regan, Cyrill 2011. “The Trinity in Kant, Hegel, and Schelling”. In: Oxford Handbook of the Trinity. Edited by Gilles Emery and Matthew Levering, Oxford: Oxford University Press, 254–266.
  • Pérez, Ángel 2012. “The Trinitarian Concept of Person”. In: Rethinking Trinitarian Theology. Edited by Robert Wozniak and Giulio Maspero, London: T&TClark, 105–145.
  • Porro, Pasquale 2016. “Qualche riferimento storiografico sulla distinzione di essere ed essenza”. In: Tommaso d’Aquino, L’ente e l’essenza, Milan: Bompiani, 183–215.
  • Porro, Pasquale 2017. Tommaso d’Aquino. Un profilo storico-filosofico. Rome: Carocci.
  • Powell, Samuel 2001. The Trinity in German Thought. Cambridge: Cambridge University Press.
  • Priest, Grahamm and Francesco Berto 2017. “Dialetheism”. Stanford Encyclopedia of Philosophy.
  • Pugliese, Marc 2011. The One, the Many, and the Trinity: Joseph A. Bracken and the Challenge of Process Metaphysics. Washington: Catholic University of America Press.
  • Rescher, Nicholas 1996. Process Metaphysics. New York: SUNY Press.
  • Seibt, Johanna 2018. “Process Philosophy”. Stanford Encyclopedia of Philosophy.
  • Splett, Jörg 1965. Die Trinitätslehre G.W.F. Hegels. Munchen: Alber.
  • Surin, Kenneth 1986. “The Trinity and Philosophical Reflection: a Study of David Brown’s The Divine Trinity”. Modern Theology 2, 235–256.
  • Swinburne, Richard 1997. “Evidentialism”. In: Companion to Philosophy of Religion, ed. Charles Taliaferro, Paul Draper, Philip Quinn, Oxford: Blackwell, 681–687.
  • Taliaferro, Charles 2003. “The Trinity and Natural Reason: Lessons from Cambridge Platonism”. In: The Trinity: East/West Dialogue. Edited by Melville Stewart, Dordrecht: Springer, 179–187.
  • Tripodi, Paolo 2015. Storia della filosofia analitica. Rome: Carocci.
  • Tuggy, Dale 2016. “Trinity”. Stanford Encyclopedia of Philosophy.
  • Tyn, Tomas 1991. Metafisica della sostanza: partecipazione e analogia entis. Bologna: Esd.
  • Varzi, Achille 2008. Parole, Oggetti, Eventi. Rome: Carocci.
  • Varzi, Achille 2019. “La metafisica nella filosofia analitica contemporanea”. In: Storia della metafisica. Edited by Enrico Berti, Rome: Carocci, 355–384.
  • Ventimiglia, Giovanni 1989. “La relazione trascendentale nella Neoscolastica”. Rivista di Filosofia Neoscolastica 81, 416–465.
  • Ventimiglia, Giovanni 2007. “La Trinità vocabolario del mondo”. In: Dio-Trinità tra filosofi e teologi. Edited by Piero Coda and Massimo Donà, Milan: Bompiani, 9–30.
  • Verene, Donald 2007. Hegel’s Absolute. An Introduction to Reading the Phenomenology of Spirit. New York: SUNY Press.
  • Wainwright, William 2009. “Theology and Mystery.” In: Oxford Handbook of Philosophical Theology. Edited by Thomas Flint and Michael Rea, Oxford: Oxford University Press, 78-102.
  • Weed, Jennifer 2019. “Religious Language”. Internet Encyclopedia of Philosophy.
  • Weeks, Anderson 2004. “Process Philosophy: Via idearum or Via negativa?” In: After Whitehead. Edited by Michel Weber, Frankfurt: Ontos, 223–266.
  • White, Thomas 2016. “Divine Simplicity and the Holy Trinity”. International Journal of Systematic Theology 18, 66–93.

  1. For a critique, see Surin 1986. ↩︎

  2. The two things are intimately connected, as clearly shown by Micheletti (2018, 157–170). ↩︎

  3. Some interpreters also conclude that, if Aquinas considers relationality and multiplicity as transcendentals of the entities, then God is relationality and multiplicity (see Migliorini 2019; Ventimiglia 2007; Gunton 1991). ↩︎

  4. Anti-Trinitarians included Thomas Hobbes (1588–1679), Matthew Tindal (1655–1733), and to some extent also Kant (see O’Regan 2011, 254–266). ↩︎

  5. Three infinite minds coordinated in mutual consciousness. ↩︎

  6. This approach is based on the observation that pagans had already imagined triads, and therefore argues that the Trinity may be a hypothesis of reason (see Taliaferro 2003, 179–187; Dixon 2003, 89; Griffiths, 1996). ↩︎

  7. The interpretation of Leibniz’s monadology is complicated, partly because there is no certainty about Leibniz’s sincerity in affirming certain doctrines (Mugnai 2001a, 127 and 163). ↩︎

  8. Leibniz also describes 'aggregates' of monads in which the monads are constitutive principles, but not parts of the aggregate, just as points can be 'in' a line but are not 'part' of it (the points exist only as limits of a line when it is 'cut') (see Mugnai 2001a, 159). If this is true, monads contained in the aggregates are formally distinct, but actually continuous (i.e. fused into one dominant monad, of which they are simple modes). ↩︎

  9. See also O’Regan 2011; Mancinelli 2009; Mura 2009; Powell 2001; Splett 1965. ↩︎

  10. Hasker 2013, ch. 21. ↩︎

  11. On analogy-univocity, see Weed 2019. ↩︎