Love and the Necessity of the Trinity: An A Posteriori Argument

Abstract

This article aims to provide an a posteriori argument from love for the Trinity. A reformulation of the argument from love is made by proposing a novel version of the argument that is situated within an objective, empirical, natural theological framework. Reformulating the argument in this specific manner will enable it to ward of an important objection that is often raised against it, and ultimately render this argument of great use in establishing the necessity of the Trinity.

1. Introduction

According to Richard Swinburne (1994, 2018), there is a cogent argument from love for the necessity of the doctrine of the Trinity—which we can term the ‘Love Argument’. The doctrine of the Trinity (hereafter, the Trinity) is the Christian teaching that posits the existence of three persons (Greek: hypostases), who are each equally divine through them sharing in the one divine nature (Greek: ousia). In Swinburne’s thought, who follows in the footsteps of the 12th century medieval theologian Richard of St. Victor,1 if there exists a solitary divine person, defined as an essentially everlastingly omnipotent person, then one can know a priori that it is necessarily true that this divine person will everlastingly generate two other interdependent divine persons—in order for him (and them) to exemplify perfect love. Perfect love, for Swinburne (2018), is a love that has at least two characteristics: mutuality and unselfishness. Thus, in order for this type of love to be exemplified by the solitary divine person, there must also exist a minimum of two other persons of equal status (i.e., two other divine persons). Given this requirement, the existence of the Trinity is thus a necessary truth.

Unpacking this further, we can see that, for Swinburne (2018), perfect love would, firstly, be a mutual love, in the sense that it is a good state of affairs for a being to mutually give to another what is good for them. Thus, mutual love involves the total sharing of one’s self with another equal by reciprocally giving all that is good for oneself to the other—as in a perfect marriage—which would produce a love that is reciprocated in quantity and kind (Swinburne 1994, p. 177). Secondly, perfect love would also be an unselfish love, in the sense that it would be a bad state of affairs for a twosome to be solely focused upon their interests, and thus having no desire to spread the love that they have for each other with another being (Swinburne 2018, p. 16). The unselfish nature of love—unlike what would be found within a deficient marriage—would, therefore, involve the co-operation of the twosome in seeking to benefit others. Furthermore, the twosome would seek the good of each other by finding a third person for them to love and be loved by—such as it is found in a couple seeking to extend their family through procreation (Swinburne 2008, p. 31). Thus, at a more general level, this would be that of the first being co-operating with the second being to further share all that is good for them with a third equal being. Perfect love would thus be unselfish through the twosome seeking to fulfil their wish that there is another equal in whom one’s beloved can love and be loved by.

In summary, perfect love, according to Swinburne, would thus be a mutual and unselfish type of love that is ‘a supreme good’ (Swinburne 1994, p. 191). And by perfect love being a ‘supreme good’, it would present God with a unique best possible action that, as a perfectly good being, he must perform. In other words, the exemplification of perfect love by the solitary divine person: d₁, would be an overall best action (or more specifically a unique best possible action) and thus there would an ‘overriding reason’—a reason that supports an action as being sensible, appropriate, reasonable and rational to be performed—for d₁ to inevitably and everlastingly generate another divine person: d₂—so as to share their love with one another. Furthermore, it would also be an overall best action for d₁ and d₂, to co-operate with one another to inevitably and everlastingly bring about another divine person: d₃—so as for them together to share their love with another and provide another person for their beloved to love and be loved by.2 Thus, given the nature of love that is in play here, if there is one divine person, then, necessarily, there will be two other divine persons—knowledge of which is obtainable a priori.3

Or, so it seems, as one can raise (what we can call) the Intuition Objection, against the a priori Love Argument (hereafter, the A Priori Argument) that has been proposed here by Swinburne. That is, according to the Intuition Objection, the A Priori Argument appears to lack support from any objective reasons for its central a priori premise: the perfect love (and goodness) of a divine person would necessitate the existence of two other divine persons. Specifically, in the mind of the Intuition Objector, the A Priori Argument seems to be based solely on an intuitive foundation concerning the nature of love. Yet, the problem is that intuitions can easily be misguided,4 and so one can certainly raise questions concerning the reasons why the specific aspects of the nature of love in the A Priori Argument—mutuality and unselfishness—should be taken to be ‘great-making’ aspects of love, rather than any other potential aspects of it? Why should mutual and self-less love be a better form of love than self-directed love? As one may argue, along with Harry Frankfurt (2004, pp. 69–100), that it is in fact self-love which is the perfect manifestation of love, and thus the mutuality and unselfishness aspects of love are, in fact, not great-making ones. Importantly, however, this is not to say that there are no reasons that can be adduced for one to rationally privilege mutual and unselfish love over that of self-love. Rather, the key point here, according to the Intuition Objection, is that, outside of an intuition, there has been no reason given by Swinburne to accept the specific conception of the nature of love that features in the A Priori Argument (with its Trinitarian implications) over that of any other conception of love (which might lack these implications). Thus, one does not have any good reason to believe that we can, in fact, obtain knowledge concerning the necessity of the Trinity from an a priori standpoint. In short, further good (and potentially ‘overriding’) reasons will need to be provided for one to believe that it is, in fact, a necessary truth that there are three divine persons—so, the question now becomes: are there any?

The rest of this article will focus on answering this question and, more importantly, the Intuition Objection, through reformulating the Love Argument in two significant ways: first, by explicating and grounding the argument upon an a posteriori philosophical foundation, which will help us to free the argument from its intuition-based foundation. And, second, by expounding a specific form of love—agapê, which will serve as the concept of love that supports the case for it being a necessary truth that, if there is one divine person, then there also must exist exactly two other divine persons. More specifically, this article will utilise two philosophical theses to reformulate the Love Argument: first, the influential philosophical notion of the necessary a posteriori, introduced by Saul Kripke, and, second, the concept of love: agapê, proposed by Alexander Pruss.5 These two theses, in combination, will provide us with a grounded epistemological framework and some objective reasons for believing in the necessity of the Trinity—ultimately enabling the Love Argument to ward off the Intuition Objection (and two further objections, each of which will be further detailed below). The Love Argument will thus be shown to have some bright prospects for future Trinitarian theorising.

However, before we set off on our reformulation of the Love Argument, it will be helpful to make clear two specific linguistic points that will be expressed throughout: first, the name ‘God’ will be used over that of the generic term ‘solitary divine person’, and this name will be used to designate a single ‘person’: The Father, rather than the Trinity composed of the Father the Son and the Spirit, as it did in the A Priori Argument (and by other Social Trinitarians as well).6 And thus, within the present account, God is numerically identical to a person, the Father, who is a member of the Trinity. In other words, there are three divine persons within the Trinity: the Father, the Son and the Spirit—each of whom possesses the one divine nature, and thus can equally be called ‘God’, in the predicative sense—yet, the one ‘God’, in the nominal sense (i.e., as a name), is to be identified as the Father alone.7 Second, the predicate that expresses the property of being the person that inevitably causes to exist two other divine persons, which is ascribed to God within the Love Argument, will now, in its short form, be termed the property of being the Father, rather than the property of being tri-personal, being tri-une or, being Trinitarian, as was also the case in the A Priori Argument.8 Thus, the central focus of the reformulated argument that is to be defended here is that of all individuals being to obtain knowledge concerning the necessity of God (i.e., a single divine person) being the Father (i.e., the person who inevitably brings about two other divine persons), which will further entail the existence of the Trinity being a necessary truth. The conclusion of the present proposal is, therefore, the same as that of the A Priori Argument; however, the manner and terminology that one is using to reach that conclusion will be different.

Thus, taking all of these things into account, the plan is as follows: in Section 2 (‘Necessary A Posteriori: The Essentialist Route’), I briefly explicate the notion of essentialism and the necessary a posteriori introduced by Saul Kripke. Then, in Section 3 (‘Necessary A Posteriori: The Trinitarian Essentialist Route’), I apply these two notions within a Trinitarian context, which will help me to map out an essentialist route to a Trinitarian necessary a posteriori and detail the justification and discoveries provided by this route, which all help the Love Argument to ward off the Intuition Objection. In Section 4 (‘Prospects: Further Benefits of the A Posteriori Argument’), I detail the prospects of this argument, which centres on its ability to also ward off two further objections against the A Priori Argument. Finally, in the concluding section (‘Conclusions’), I summarise the above results and conclude the article.

2. Necessary A Posteriori: The Essentialist Route

According to Saul Kripke (1980, 2008), there is an important distinction to be drawn between the notions of a prioricity and necessity. More specifically, as Kripke (1980) notes, on the one hand, an a priori true statement is one that is known to be true, independent of experience. A prioricity is thus a concept of epistemology, based on the fact that it concerns the way in which someone can know something to be true. Whereas, on the other hand, a necessarily true statement, as is also noted by Kripke (2008), is one that is true and could not have been otherwise.9 Necessity is thus a concept of metaphysics, based on the fact that it concerns the modal structure of reality. Thus, as Kripke writes, with the notions of a prioricity and necessity, we are ‘dealing with two different domains, two different areas, the epistemological and the metaphysical’ (Kripke 1980, p. 36) In short, we thus have two different concepts from two different domains:

Philosophical Concepts and Domains
A Prioricity	Necessity
Philosophical Concept: Knowledge Philosophical Domain: Epistemology	Philosophical Concept: Modality Philosophical Domain: Metaphysics

A prioricity and necessity are thus not equivalent notions and, as a matter of fact, are not coextensive. That is, the fact that a statement is necessary does not mean that it can, or must, be known a priori—all necessary truths are not a priori truths. Instead, as Kripke (1980) asserts, there seem to be certain cases of necessary a posteriori truths, examples of which include certain identity statements (e.g., Hesperus is Phosphorus), theoretical identifications (e.g., Heat is molecular motion), compositional statements (e.g., Water is partly composed of Hydrogen) and essentialist statements (e.g., Saul Kripke is a human). These types of statements are taken by Kripke (and others) to be both necessarily true and only knowable a posteriori—on the basis of empirical evidence. And so, on the basis of these type of examples, Kripke has argued for the veracity of necessary a posteriori statements via two routes: the nominal route and the essentialist route.10

Focusing on the essentialist route to the necessary a posteriori (hereafter, ERNA),11 this specific route is grounded upon the notion of essentialism. Essentialism is the metaphysical view that holds to a certain range of entities being meaningfully said to have some of their properties essentially. As noted by Christopher Hughes (2004, pp. 108–9), there are, at least, three types of essentialism: hypoessentialism—all the essential properties of an individual are trivially essential to them,12 moderate essentialism—all individuals have (trivial and non-trivial) essential properties and accidental properties, and hyperessentialism—all of an individual’s properties are essential to it. Kripke is committed to moderate essentialism, in that he holds to the view that individuals have certain properties such that they could not have existed without having those properties—they are essential to them—and all of the other properties of those individuals that are not essential to them are accidental. Within this essentialist framework, Kripke believes that we have a successful route to the necessary a posteriori, as he writes, ‘...other considerations ...about an object having essential properties, can only be regarded correctly, in my view, if we recognize the distinction between a prioricity and necessity. One might very well discover essence empirically’ (Kripke 1980, p. 110). That is, in Kripke’s mind, we can indeed discover moderate essentialism to be true as the result of an empirical investigation. Specifically, Kripke sees the ERNA as being applicable to the following paradigm example(s):

(Paradigm): If Saul Kripke exists, then Saul Kripke is a human being.

Assuming that (Paradigm) is true,13 then, according to Kripke’s moderate essentialism, this proposition must be necessarily true. Yet, it is only knowable a posteriori.14 More precisely, one knows a priori that being a human is an essential property of any entity that exemplifies it. However, knowledge that Saul Kripke (if he exists) is a human is only obtainable a posteriori—it requires empirical investigation to find out if it is true. So, at a general level, and briefly taking a step back from the notion of moderate essentialism, we can state Kripke’s notion of the necessary a posteriori succinctly as such:

Necessary A Posteriori

A statement is necessary a posteriori if it is a necessary truth, and its truth-value is knowable solely through empirical investigation.

Thus, in (Paradigm), we have an example of the necessary a posteriori, as taking ‘s’ to represent the name ‘Saul Kripke’, and ‘F’ to be a predicate which expresses an essential property of s. Then, by the thesis of moderate essentialism, Fs will express a certain necessary truth. Yet, the proposition expressed by this sentence will also be a posteriori, due to the fact that it would take an empirical investigation to find out whether s has the property expressed by F. Therefore, one can know a priori that if the individual featured in (Paradigm): Saul Kripke, exemplifies the essential property stated here—that of ‘humanity’, then he exemplifies it in any possible circumstance in which he exists (Soames 2011). However, for one to discover whether it is, in fact, true would require an empirical investigation. Thus, in short, through the ERNA, one knows a priori that, if true, (Paradigm) is necessarily true. However, one can only determine the truth-value of this example (and others like it) through an a posteriori empirical investigation.

In the ERNA, we thus have two elements—a necessary a priori statement and a contingent a posteriori statement—that combine together to produce a further element—a true necessary a posteriori statement. That is, one is able to obtain knowledge concerning a necessary a posteriori truth (e.g., necessarily Saul Kripke is human) on the basis of one’s knowledge concerning a specific necessary a priori truth (e.g., if Saul Kripke exists, then he is a human) and a contingent a posteriori truth (e.g., Saul Kripke exists). So, what we see here, specifically through the lens of moderate essentialism, is that if there is a statement Q concerning something being an essential property of a specific entity P, then one can know by a priori conceptual analysis, the conditional statement: ‘if P, then necessarily Q’. However, we only know by an empirical investigation that the antecedent of the conditional is, in fact, true. Thus, we can conclude, by modus ponens, that the statement is necessary, which (along with the distinction between the elements of a necessary a priori statement, a contingent a posteriori statement and a necessary a posteriori statement) we can state formally as follows:

Necessary A Posteriori Elements	Formality (Modus Ponens)
(1) Necessary A Priori Statement (2) Contingent A Posteriori Statement (3) Necessary A Posteriori Statement	(1) (P→Q) (2) (P) (3) (Q)

The conclusion that is expressed by (3) is thus that it is necessary that the statement under question (1) is true, and this conclusion is knowable a posteriori, since, as Kripke writes, ‘one of the premises [(2)] on which it is based is a posteriori’ (Kripke 1980, square parenthesis added). This is the core of Kripke’s position concerning the necessary a posteriori, and his route to it through the ERNA. However, we can indeed further flesh out the inner workings of this approach by focusing on a distinction that is left implicit here by Kripke, but has been helpfully made explicit by Scott Soames (2011, pp. 80–83). This distinction is between epistemic possibility (i.e., conceivability) and metaphysical possibility (i.e., genuine possibility), which can be further explicated through the notion of a ‘possible world-state’.15 A metaphysically possible world-state is a maximally complete way the actual concrete universe could have been—more specifically, the maximally complete properties that the universe could have instantiated (Soames 2011). Thus, for the actual universe, there are a specific set of maximally complete properties that it could have instantiated, and there are also other maximally complete properties the universe could not have instantiated—the former are the metaphysically possible world-states, and the latter are the metaphysically impossible world-states. An epistemically possible world-state is a maximally complete way the concrete universe can coherently be conceived to be—more specifically, the maximally complete properties that the universe can be conceived of as instantiating—the instantiation of which one cannot know a priori (Soames 2011). Thus, again, for the actual universe, there are a specific set of maximally complete properties that the universe could not instantiate—metaphysically impossible world-states—which, however, one can, in fact, conceive of it instantiating and also not know a priori that it does not instantiate them—these are the epistemically possible world-states. The distinction between metaphysically possible world-states and epistemically possible world-states is thus between world-states that are genuinely possible, and one’s that can simply be conceived of as being possible, yet could, in fact, be impossible.

So, with this distinction between metaphysically and epistemically possible world-states in hand, Soames (2011, p. 80) argues that, in Kripke’s ERNA,16 the fact that one cannot know that a statement is true a priori means that one cannot know independent of experience that a specific world-state in which this statement is false is not in fact instantiated—world-states such as these are thus coherently conceivable, which renders them as epistemically possible-world states. Thus, for Kripke, statements such as ‘Saul Kripke is a human’ are necessarily true; that is, there is no possibility that Saul Kripke, for example, could be a rabbit or a robot. However, we cannot know a priori that Saul Kripke is a human, as it would take some form of empirical investigation to determine the truth value of this statement. Hence, what one can know a priori is what is stated in (Paradigm): if Saul Kripke exists, then he is a human—it is an essential property (i.e., it is necessary) that he is a human. Therefore, in knowing a priori that ‘if Saul Kripke exists, then (necessarily) he is a human’, one knows a priori that if a world-state in which it is true that ‘Saul Kripke exists’ is in fact instantiated, then there is no world-state in which it is false that ‘Saul Kripke is a human’ could have been instantiated. Thus, when one discovers through empirical investigation that it is true that ‘Saul Kripke exists’, then one also learns a posteriori that the epistemically possible world-states in which he is not a human are, in fact, metaphysically impossible. Therefore, at a general level, the reason that empirical evidence is required for knowledge of necessarily true propositions is due to the fact that this type of evidence is needed in order to rule out the metaphysically impossible, yet epistemically possible, world-states in which these statements are false. We can thus illustrate this as such through Figure 1 (with each circle representing a possible world-state, the large rectangular shape representing all of the epistemically possible world-states, the smaller rectangular shape representing the metaphysically possible world-states, the central circle (PWS(A)) representing the ‘actual’ metaphysically possible world-state—which determines the category of the other metaphysically possible world-states—P representing the statement ‘Saul Kripke exists’ is true, Q representing the statement ‘Saul Kripke is human’ is true, and ~Q representing the statement ‘Saul Kripke is human’ is false):

So, what we have here are a set of epistemically possible world-states—possible world-states that can be coherently conceived as being instantiated—which includes a system of metaphysical possibility, with a designated ‘actual’ world state and further space for related world-states (Soames 2011). That is, for each epistemically possible world-state, we recognise it to be metaphysically possible—to be a genuinely possible property that the universe can actually instantiate—if it is compatible with the designated and instantiated ‘actual’ world-state. In continuing with our example above, these epistemically possible world-states would include such statements as ‘Saul Kripke exists and is a short human’ is true, or ‘Saul Kripke exists and is a tall human’ is true.17 Hence, given the supposition that the designated ‘actual’ possible world-state is instantiated, then one cannot conceive of any possible world-state, relative to it, in which the statement ‘Saul Kripke exists’ is true, and the statement ‘Saul Kripke is a human’ is false (such as possible world-states where the statements ‘Saul Kripke is a rabbit’ or, ‘Saul Kripke is a robot’ are true.). Once one reaches the conclusion that a certain epistemically possible world-state is to be designated as the instantiated ‘actual’ world-state, which is achieved through an a posteriori empirical investigation, then one considers the compatible epistemically possible world-states as being metaphysically possible and the incompatible epistemically possible world-states as being metaphysically impossible. Thus, as Soames (2011, p. 83) notes, for any world-state to be metaphysically possible, it must be a metaphysically possible (or genuinely possible) member of some epistemically possible system of metaphysical possibility that is compatible with the designated ‘actual’ world state—a possible world-state that captures the state that the world is actually in, knowledge of which is obtainable by an a posteriori empirical investigation.

Taking all of these things into account, we thus can now utilise the notion of the necessary a posteriori to provide a reformulation of the Love Argument. To this task, we now turn.

3. Necessary A Posteriori: The Trinitarian Essentialist Route

In reformulating the Love Argument, we start by generalising it in a manner that now takes it to be a term designating a kind (or category) that houses a family of different types of arguments.18 Specifically, rather than the Love Argument referring solely to Swinburne’s (or Richard of St Victor’s) version of it,19 it now refers to any argument from love for the necessity of the Trinity. Thus, off of this generalisation, we can now state that there are two sub-categories of arguments within the kind (or category) Love Argument: the A Priori Argument and the A Posteriori Argument. The A Priori Argument and the A Posteriori Argument are thus different types of arguments for the necessity of the Trinity that fall into the same kind (or category), with the differentiating factors between these two types of arguments being as follows:

Love Argument
A Priori Argument	A Posteriori Argument
Concept of Love: Intuition Based Philosophical Methodology: Necessary A Priori	Concept of Love: Empirical Revelation Based Philosophical Methodology: Necessary A Posteriori

The species distinction between the A Priori Argument and the A Posteriori Argument is thus grounded upon two things: the concept of love and the philosophical methodology that is utilised to reach the conclusion. More specifically, in the A Priori Argument, the nature of love is intuitively based, in the sense that it seems to be the case for individuals like Swinburne (and other proponents of this argument) that a paradigm form of love must have the characteristics of mutuality and unselfishness. The A Posteriori Argument, however, fixes the nature of love on a particular conception of it: agapê, which is taken by the proponents of the argument to be the empirically revealed conception of love.20 The A Posteriori Argument thus takes agapê to be based on a universally accessible revelation that has been provided by God.21 Fixing the concept of love in this empirically-grounded way thus provides the Love Argument with an objective, rather than a subjective, foundation.

Furthermore, in the A Priori Argument, the philosophical methodology that is utilised to reach the conclusion that the existence of the Trinity is a necessary truth is purely a priori—it’s completely independent of experience. That is, in the A Priori Argument, on the basis of the nature of love noted above (and the concept of God, defined as an essentially omnipotent, and thus perfect good person) God will inevitably bring about two other divine persons. One can thus obtain knowledge a priori concerning the necessity of the Trinity—one can obtain this knowledge simply by thinking deeply about the nature of love and the implications of it for the actions that God must perform. In contradistinction to this, the philosophical methodology that is utilised in the A Posteriori Argument to reach the conclusion that the existence of the Trinity is a necessary truth has three components: a necessary a priori component, a contingent posteriori component and a necessary a posteriori component. More specifically, on the basis of one’s knowledge concerning the truth of a specific necessary a priori statement, in combination with that of a contingent a posteriori statement, we can derive the truth concerning a further necessary a posteriori statement. However, the specific necessary a priori statement that is at the centre of the A Posteriori Argument is not the statement ‘If God is perfectly good (or perfectly loving), then he will be the Father’—which is found within the A Priori Argument.22 Rather, given the empirical, revelatory basis grounding the nature of love that will be posited here, the target statement is taken to be the following:

(Target): If there is a God and love is revealed as a duty-imposing, multi-formed agapê, then necessarily God is the Father.

So, in taking (Target) to be the statement under analysis, and applying the A Posteriori Argument’s philosophical methodology (the ERNA) within this specific theistic context, we can formulate a modus ponens for this case as follows:23

Necessary A Posteriori Elements	(Necessary) A Posteriori Argument
(1) Necessary A Priori Statement	(1) (P∧Q→R) If there is a God and love is revealed as a duty-imposing, multi-formed agapê, then necessarily God would be the Father.
(2) Contingent A Posteriori Statement	(2) (P∧Q) There is a God and love is revealed as a duty-imposing, multi-formed agapê.
(3) Necessary A Posteriori Statement	(3) (R) Necessarily, God is the Father.

Premise (1) is a necessary and a priori truth, and premise (2) is a contingent claim that is knowable only a posteriori. And thus, if one knows (1) and (2), then one can then deduce premise (3), which is a truth that is an instance of the necessary a posteriori. In other words, once one knows (1) and (2), then they are in a position to also obtain knowledge of (3), which posits of this a posteriori statement that it is necessary. So, in stating this more precisely, and taking ‘g’ to be representative of the name ‘God’, and F to be a predicate which expresses the essential property of being the Father. Then, assuming the position of moderate essentialism—which the A Posteriori Argument does—Fg will express a certain necessary truth, that of premise (3): ‘Necessarily, God is the Father’. However, the proposition expressed by this sentence will also be a posteriori—it is a necessary a posteriori statement, due to the fact that it would take an empirical investigation to find out whether g does, in fact, have the essential property of being the Father, which is conveyed by F. Thus, what one can know a priori, is what is expressed by premise (1): if God exists (as defined in a certain way) and the nature of love is revealed as a duty-imposing, multi-formed agapê, then God will exemplify the essential property of being the Father (i.e., he would necessarily be the divine person that causes two other divine persons to exist) in any possible circumstance in which he exists. However, for one to discover whether the antecedent of this necessary a priori conditional statement is, in fact, true, it would require an empirical investigation into the contingent a posteriori statement that is expressed by premise (2): that God does exist and love is revealed as a duty-imposing, multi-formed agapê. Thus, in short, through the A Posteriori Argument, which is grounded upon the ERNA, one knows a priori that if (1) is true, then (3) is necessarily true. However, one can only determine the truth of (1) through an a posteriori empirical investigation into (2), which results in (3) of the A Posteriori Argument being an instance of the necessary a posteriori.

This argument does seem to be highly plausible; however, one can ask the important question of what reasons do we have for believing (1) and (2) to be true? To answer this question, it will be vital now to detail the reasons to believe, first, that premise (1) is indeed a necessary statement—knowledge of which is obtainable a priori. And, second, that we have reasons to believe the truth of (2), which expresses the fact of the antecedent featured in (1) holding in the actual world—knowledge of which is thus obtainable a posteriori. So, we can now turn our attention towards answering these two questions. However, we will do so in reverse order, which will be helpful for pedagogical purposes.

3.1. Empirical Discoveries: God and Agapê

At the centre of premise (2) are the following discoveries, knowledge of which is obtainable a posteriori:

Contingent A Posteriori Statement

(2) (P∧Q) There is a God and love has been revealed as a duty-imparting, multi-formed agapê.

Premise (2) is a contingent a posteriori statement—one that could be false and is discoverable through empirical investigation. We can begin to further unpack this statement by splitting it into two discoveries: the existence of God and the revealed nature of love as a duty-imparting, multi-formed agapê.

The first empirical discovery, which we can derive from the natural theological work of Richard Swinburne (2004, 2016),24 can be stated more precisely as follows:

(E1) There is a God, identified as an essentially, everlasting omnipotent person.

This discovery is empirical, a posteriori data, which is grounded upon various observable phenomena. It will be helpful to now briefly unpack this discovery in more detail.

The Existence of God: God, according to Swinburne (2016, pp. 261–83), is defined as an essentially eternally omnipotent person who exists (somehow) necessarily.25 More specifically, God exists eternally in the sense of him existing at each moment of everlasting time and is necessary in that he is not caused to exist by any other being, or is inevitably caused to exist by a divine person that is not caused to exist by anyone.26 God is an omnipotent person in the sense of him, first, having the power to intentionally perform any logically possible action and, second, being a pure mental substance, which results in him possessing his own mental life, a privileged access to this mental life, and a capacity to perform separate intentional actions (Swinburne 2018). As an omnipotent person, God would also know the nature of the alternative actions that he can choose from, which would result in him being omniscient and perfectly free—that is, him being free from any non-rational influence determining the choices that he makes. Furthermore, being omniscient and perfectly free, God would also be perfectly good in the sense that he will always perform the best action (or kind of action), if there is one, many good actions and no bad actions (Swinburne 2016). More fully, given the exemplification of omniscience, God would know the nature of each available action that he can choose from and thus would possess knowledge of whether each action is good or bad, or is better than some incompatible action. Moreover, in recognising an action as good, God would have some motivation to perform that action, and in recognising an action as being better than another action, God would have an even greater motivation to perform it (Swinburne 2016). Hence, given the exemplification of perfect freedom, if God is situated in a scenario in which there is a best possible action (or best kind of action) for him to perform, then God will always perform that action (or kind of action).27 However, God would be situated in many scenarios—as is the case with human agents—where there will be two or more incompatible possible actions (or kind of actions) that are each as good as each other and are also better than any other action that he can perform (Swinburne 2018). Nonetheless, there also will be scenarios in which God is presented with a choice between an infinite number of incompatible possible actions (or kind of actions) for him to perform—each of which is less good than some other action (or kind of action) that he could perform—yet there is no best action (or kind of action) for him to perform (Swinburne 2018). For example, suppose that it is the best possible kind of action to create universes, then God will be presented with a choice to create a universe, and the action of creating universes would be a better action the more universes that God created. For states of affairs such as these, God’s perfect goodness will thus be exemplified by him choosing to perform one of these actions—choosing to create one universe—though him choosing to perform this particular action would not best—as there is no best possible action (Swinburne 2018). Our first empirical discovery is thus that there is a God of this specific kind—defined as an essentially eternally omnipotent person that (because of his exemplification of omnipotence) is also omniscient, perfectly free and perfectly good—and who we can obtain a posteriori knowledge of his (probable) existence on the basis of various natural theological evidence from the universe and its features (such as there being a complex universe (evidence 1) that conforms to simple natural laws (evidence 2), and these laws being such as to bring about the existence of human bodies (evidence 3), that are the bodies of conscious, morally aware persons (evidence 4), some of which have claimed to have had a religious experience (evidence 5).28 This set of natural theological evidence can then be precisely evaluated so as to allow one to take the existence of God, as defined above, as being part of our set of empirical discoveries.29 In summary, the first empirical discovery is thus that of there being a God, defined as an essentially omnipotent person who exists (in some sense) necessarily.

Turning our attention now to the second empirical discovery that has been made, which we can derive from the sexual ethics work of Alexander Pruss (2008, 2013), and which we can state more precisely as such:

(E2) God has a provided revelation, expressed by the Christian Scriptures, that identifies love as a duty-imposing, multi-formed agapê.

This empirical discovery can be divided into two parts:

(E2a) Love as a Duty-Imposing Agapê

(E2b) The Multi-Formedness of Agapê

This discovery is empirical, a posteriori data, which is grounded upon our previous discovery concerning the existence of God, and some specific testimonial data. It will be helpful to now, as before, briefly unpack this discovery and its parts in more detail.

Love as a Duty-Inducing Agapê: given the state of creation—namely, the inherent ignorance of humanity concerning certain truths—it is plausible that providing a revelation that includes within it propositional instructions (amongst other things) on how humans are to individually live a good life, and how they are to collectively thrive as a species, is a good (or equally good) action that God can perform—and thus, given God’s perfect goodness, he would indeed perform this specific action of providing a (propositional) revelation. One candidate for this specific revelation is that of the Christian Revelation that is expressed by the Christian Scriptures.30 In the Christian Scriptures one discovers that all individuals are presented with a duty to show agapê—love (John 13: 34–35).31 More specifically, as Pruss (2013, p. 9) notes, ‘the ethics of the New Testament centres around a specific duty to love’. That is, according to the Christian Scriptures—specifically that of the New Testament—every individual has a specific duty: the duty to love everyone and to act in that love in such a way that all of morality is included within this act (Romans 13:8–13). In other words, all individuals are obliged to love, and do so in an appropriate manner—to love the beloved as they are and not as what they are not (Pruss 2013). This understanding of one’s moral duty to love—to show agapê—is thus one that is focused on particular actions that are for the betterment of the beloved in the loving relationship. Additionally, this specific duty provided by agapê implies three reasons why love is not to be conceived as, or reduced to, a static feeling or emotion. The first reason is that loving feelings or emotions are not under volitional control, whereas one is always obliged to love (Pruss 2013). The second reason is that feelings are often transitory and thus can be lacking in certain times of distress, whereas the New Testament sees love as being best exhibited in situations of great distress—such as during the suffering of Christ (Mark 15:34). The third reason is that feelings are not closely connected to action—they do not always need to be acted on, but instead can wilfully be ignored (Pruss 2013). However, as Pruss (2013, p. 9) notes, within the New Testament, agapê is seen as being the fulfilment of the moral law, and thus ‘it is taken for granted that love expresses itself and is sufficient, in and of itself’. Agapê is thus not a feeling, but neither is it a disposition or tendency to feel an emotion—as dispositions are even less under direct volitional control than feelings and thus cannot serve as a guarantor for right action (Pruss 2013). From this non-reducibility of agapê to a feeling or disposition, we can see that action is a central component of agapê, and as actions are an expression of an individual’s will, agapê is to be conceived of as a determination of the will of an individual in favour of the beloved (Pruss 2013). The duty for all individuals to love agapeically, expressed by the determination of one’s will in favour of another, is contained as teaching within the Christian Revelation, expressed through the Christian Scriptures, and thus we are able to take this as being part (a) of our second empirical discovery. We can now focus on part (b) of our second empirical discovery: the multi-formedness of agapê.

The Multi-Formedness of Agapê: the various forms of love—filial, romantic or fraternal love etc.—are all forms of agapê. That is, according to the New Testament, agapê is not a distinct type of love alongside the other forms of love; rather, it simply is love, a multi-formed love. Moreover, this multi-formedness of agapê is grounded upon two factors: linguistic and theological. Linguistically, within the New Testament, all ‘types’ of love are forms of agapê in the sense that the word has a very wide range of meaning, such that spousal love (Ephesians 5:25), sexualised love (Song of Songs 2:5), and even love for certain possessions—such as the love for the best seats in the synagogue (Luke 11:43)—are all referred to as agapê (Pruss 2013). In short, the New Testament usage of agapê appears to have a semantic range that corresponds to that of the English word ‘love’ (Pruss 2013). Furthermore, at a theological level within the New Testament, all ‘types’ of love are forms of agapê in the sense that the love that humanity is to have for God and for their neighbour (Matthew 5:44), and the love that God has for humanity (John 3:16), is regularly referred to as agapê, and is expressed as a selfless generosity that is directed towards the other and desires reciprocation for the good of the other (Pruss 2013). Given this wide range of linguistic and theological usage, the scriptural understanding of agapê does not distinguish it from other forms of love; rather, it presents the forms of love as unified forms of agapê—every love is agapê, a multi-formed love.

The conception of agapê as a multi-formed love that is based on action is also contained as teaching within the Christian Revelation, expressed through the Christian Scriptures, and thus we are also able to take this as being part (b) of our second empirical discovery. The second empirical discovery is thus that of there being a duty to show agapê—a multi-formed love—towards all individuals, and this is contained within the Christian Revelation. Taking these two discoveries together, we thus reach the conclusion that there exists a God and that the nature of love is that of a duty-imposing, multi-formed agapê, which has been revealed by God, as attested to by the Christian Scriptures. From this empirical investigation, we can now turn our attention onto the a priori conceptual analysis of (1).

3.2. A Priori Conceptual Analysis: Agapê and God

At the centre of premise (1) is the following conditional statement, knowledge of which can be obtained by a priori conceptual analysis:

Necessary A Priori Statement

(1) (P∧Q→R): If there is God and love has been revealed as a duty-imposing, multi-formed agapê, then necessarily God would be the Father.

Premise (1) is a necessary a priori statement, which is one that could not be false, no matter how different the world could’ve been, and this is discoverable independent of experience. That is, one can obtain knowledge a priori that if the antecedent is true, then the consequent will be true, and necessarily so, given the notion of moderate essentialism (the thesis that individuals have (trivial and non-trivial) essential and accidental properties) that underpins this statement. How one can indeed see this to be the case is by providing an a priori conceptual analysis of the main features of the conditional statement. More specifically, the focus will be on further elucidating the notion of agapê that is found within the sexual ethics work of Pruss (2008, 2013). Through this elucidation, we will thus provide a conceptual analysis of:

(A)

Three Aspects of Agapê

(B)

Nature of Romantic Love

(C)

God’s Fulfilment of the Duty to Agapê

These three parts are further concepts, knowledge of which is obtainable a priori through a conceptual analysis of the nature of agapeic love and the specific requirements for God to be the Father, given his perfect goodness and the features of this love. It will be helpful to now further unpack these concepts in more detail.

Three Aspects of Agapê:agapê is best understood as a duty-imposing, multi-formed love that is a determination of the will of an individual in favour of the beloved. Agapê is thus a concept that is connected to action—it guarantees right action—and thus, individuals are responsible for love, rather than being passive receivers of it (Pruss 2013). To fulfil this responsibility, one must love by willing the good for the beloved—for their sake, rather than one’s own—but also one must appreciate the beloved and seek union with them. There are thus, at least, three aspects of all forms of agapê:

• appreciation
• benevolence (willing the good to the beloved)
• striving for union.

These three aspects of agapê are interconnected as follows: a true appreciation of the beloved would result in a recognition that it is right to bestow goods on them through acts of will (Pruss 2013). Moreover, appreciation of the beloved would lead to one seeking union with them in such a way that the beloved’s good becomes that of the lover’s good as well (Pruss 2013). By willing the good for the beloved for their sake, one would appreciate them as an individual who it is appropriate to bestow goods upon, and one would also be united with the beloved in will, given that the beloved would also will the good for themselves. Additionally, by one aiming for an intimate form of union, where one would treat the good and bad experiences that befall the beloved as befalling themselves, it would thus be natural that the lover would appreciate the beloved as one who is worthwhile of experiencing the good, resulting in one naturally willing the good for the beloved (Pruss 2013). These three aspects of agapê provide a basis for there to be a self-less and generative love between the lover and the beloved.32

Moreover, all the various forms of agapê—all the various types of agapeic relationships—will include these three aspects within them, yet they will be manifested in different ways. That is, each form of love—self, romantic, filial and fraternal love etc.—will exhibit, in distinct ways, an appreciation of the beloved, the willing of their good and a striving of some form of union with them. Precisely, the differentiation between the forms of agapê will be distinguishable by the type of union that one is impelled to enter into—with the type of union that is appropriate between the lover and the beloved depending, in part, on the characteristics of the individuals (Pruss 2013). It will thus be important to now detail the nature of the two possible types of union: formal union and real union, that play a part in distinguishing the different forms of agapê.33

The formal union between a lover and their beloved is a union of mind and will. This union of mind and will consists of a mutual ‘indwelling’ of the lover and beloved—even in the cases of unreciprocated love. In this mutual indwelling, the lover has the beloved ‘living within their mind’ and strives to understand the nature and goals of the beloved from their perspective—understanding the beloved from the inside—which leads to a willing of the other’s particular good and the performance of actions for the sake of the lover as if the beloved were the lover themselves (Pruss 2013). In a certain way, love is ek-static,34 in the sense that through their union, the lover comes to live outside of themselves and in the lover. Hence, in a loving relationship, the lover dwells in the beloved intellectually and in will, and, in turn, the beloved dwells in the lover intellectually and in will as well (Pruss 2013). There is thus a formal union that can be increased as one gains a better knowledge of the beloved—enabling the lover to understand what is good and bad for this particular beloved and understand them better from their own point of view. Moreover, one’s will is united with the beloved by willing the good for them, and thus this formal union is derivable from the appreciative and benevolent aspects of love and is therefore always present in every case of love. Formal union is present simply in virtue of one loving another, and thus can exist without reciprocation, as Pruss writes, ‘formal union is already achieved at any time love is there…formal union can exist without any reciprocation’ (Pruss 2013, p. 32). However, the love that is present in a relationship nevertheless impels one toward real union. Real union is thus the external expression of the formal union between the lover and the beloved. That is, real union is the way that the lover and the beloved, who are each united in mind and will, are together in a particular manner that is determined by the nature of the form of love that is present (Pruss 2013). Real union is the reciprocation of love that achieves an additional union between the lover and their beloved through a shared activity. Agapê thus makes an individual seek real union with another, with the specific form of real union that is sought being the primary distinguishing factor between the different forms of agapê. For example, filial love might require physical touch—such as hugging a child—whilst the friendly love between two colleagues might not call for this expression of their union—where an intellectual conversation might be more appropriate for this type of relationship (Pruss 2013).

The love between people must thus take on a form that is appropriate to the lover, the beloved and their relationship, with some type of real union being paradigmatic of the form of love between them. Love, construed as agapê, thus must be dynamic and responsive to the reality of the beloved, which results in it taking on a form that is determinative of the manner in which the lover and the beloved express the union between them (Pruss 2013). More specifically, agapê has many general forms—e.g., self-love, romantic love, filial love and fraternal love—however, these forms also have various sub-forms—e.g., the romantic love between newly-weds of such-and-such an age, and the romantic love between a husband and a wife of such-and-such an age who have been married for such-and-such number of years. In a loving relationship, one is thus required to be sensitive to the situation that they are in and the person with whom they are in a relationship, which will be the basis for the form, or sub-form, of love that is instantiated within the relationship. Thus, as Pruss (2008, §3) importantly notes:

The form of love appropriate between two young and healthy newly-weds and expressed through a companionship that is both sexual and otherwise needs to be different from the form of love expressed by an elderly person’s changing the soiled underclothes of a bed-ridden spouse. Yet there is a continuity: the couple hasn’t lost their love, but their romantic love has matured to a different form or, better, sub-form.

Thus, agapê does not change forms, but is dynamic in such a sense that the sub-forms of a particular form of love, and the manner in which their union is expressed, can change, dependent on the characteristics of the individuals within the relationship. Nevertheless, what would not be changeable within an agapeic relationship would be the fact that the achievement of a real union between the lover and their beloved will have an external expression—a ‘consummation’ of the form of love that is present. Paradigmatically, the consummation of a real union would thus be a shared activity that expresses the distinctiveness of the type of relationship that is present and enables the love to be fulfilled with respect to the particular form that it takes. The unitive aspect of love is thus fulfilled by this consummation, which includes—in all forms of love—a psychological union, and for a specific form of love—romantic love—a physical union as well.35 However, a hypothetical objector to the position that has been reached here can indeed raise the question of whether the unitive aspect of love can be fulfilled, and thus the relationship that is present, be consummated, in a self-love context? More specifically, is ‘self-love’, in fact, a form of agapê that cannot exhibit this unitive characteristic? As, within a self-love context, it is presumably easy to understand what it means for one to exhibit the aspects of appreciation and the willing of one’s own good. However, it is indeed challenging to understand what it means to have, or at least strive for (formal and/or real) union with oneself. As it seems to be the case that union is only possible between two distinct objects. Yet, one cannot be distinct from oneself. And thus, one cannot be (formally and/or really) united with oneself. Given this, our hypothetical objector can state that the ‘revealed’ thesis that all the distinct forms of love are all simply forms of agapê, seems to be incorrect, as the unitive aspects of love cannot be exhibited within this specific self-love context. Or, is that so? As there is plausible means of dealing with this issue that has been proposed by Eleonore Stump (2010, p. 100) in a related context, where she states:

This objection…fails to take account of the fact that a person can be divided against herself. She can lack internal integration in her mind, and the result will be that she is, as we say, double-minded. She can also lack whole-heartedness or integration in the will. Aquinas describes a person who lacks internal integration in the will as someone who wills and does not will the same thing, in virtue of willing incompatible things, or in virtue of failing to will what she wills to will. There is no union with herself for such a person.

Thus, taking our leave from Stump, the possibility of achieving a formal and/or real union with oneself is possible if we understand this as a striving for internal integration. Thus, self-love is an appreciation of oneself, the willing of good for oneself and a striving for formal and/or real union with oneself—understood now as a striving for the internal integration of oneself. The unitive aspect of agapê is thus present within a self-love context in cases of internal disintegration. Self-love, as with all forms of agapê, is one that can indeed be consummated through the expression and fulfilment of an integrated union with oneself. Taking all of these things into account, from part (A) of our conceptual analysis of the nature of agapê, we can understand it to be a singular notion that unifies the various forms of love and includes within it the aspects of appreciation, benevolence, a formal union and striving for a real union with one’s beloved. We can now focus our attention on part (B) of our conceptual analysis, which is that of an analysis of an important form of love: romantic love, and what exactly is appropriate to it.

Romantic Love: romantic love, as with all the other forms of agapê, includes an appreciation of the beloved, a will to further the beloved’s good, a formal union between the lover and the beloved and a striving for a real union between them. These aspects, as noted previously, are thus present across the different forms of love. And thus, the means by which one can distinguish romantic love from the other forms of love is the distinctive type of real union that is consummated in it—the directedness towards procreative ‘one body’ union. This directedness is definitive of romantic love, as Pruss (2013, p. 146) writes:

It is highly plausible that romantic love involves a desire for a sexual union as one body—for a total sharing, total union, at the bodily level. But this union is constituted, I have argued, by a mutual biological striving for reproduction. In desiring union, the members of the couple are implicitly desiring the biological striving that constitutes it.

The deep longing for union that is present within romantic love provides the grounds for the position that if this type of union is possible in sexual activity, then this union as one body is what romantic love would thus seek to instantiate (Pruss 2013). Therefore, the real union exhibited in a genuine case of romantic love is best understood as a functional and organic union as ‘one body’—a sexual activity involving an ‘organic union’. More precisely, the sexual union that is exhibited in romantic love is very much like the kind of functional organic unity of body parts. At a more general bio-physical level, organic union requires co-ordination between the actively functioning parts of a body and the striving of these parts for a common goal (Pruss 2008). The functioning parts of the body are thus interconnected by their coordinated striving for a common purpose. For example, an organism’s heart and arteries are organically united due to the fact of them cooperating with one another to fulfil the goal of oxygenating the body of the organism. The organic union of parts, according to Pruss (2013), is thus best defined as the parts striving together for a common purpose. Analogously, the sexual union between the lover and beloved is that of a physical striving for the procreation of a new human person. This striving is expressed through the biological, sexual activity of intercourse, and thus, in this sense, the lover and beloved are united as ‘one flesh’ through this reproductive striving. In a sexual union, two persons are united in a totality that involves them as persons and physical, embodied beings (Pruss 2008). The real union present within romantic love is thus sexual union, which is a union of the lover and beloved as ‘one organism’ and ‘one body/flesh’ in a manner that is analogous to the union between the distinct biological parts of an organism (Pruss 2008). Thus, in short, the union present in romantic love is thus akin to the way in which the parts of a human body are united at a biophysical level—just as the body is unified by its co-operative activity for a common purpose, lovers are also united by their co-operative activity for a common purpose. However, if the union is to be a good and significant one, then the goal that is striven for will need to be valuable and of proportionate significance. Thus, it is the common striving for a significant purpose: the biological striving for reproduction, which results in the lover and beloved being one body. This sexual union, construed as the functional union of the lover and the beloved as one body, is constituted by a mutual striving for reproduction that is co-operative and mutually regulated by the individuals in love (Pruss 2013). Reproduction is thus the biological goal of the union present in romantic love, and this goal, and the striving for it, are in and of themselves goods to be sought, due to the fact that the couple, by achieving this union, is able to instantiate a richly layered union: a higher-level psychological union and a lower-level biological union—with the ‘lower-level’ activity of the lovers being biologically directed at the procreation of offspring and the ‘higher-level’ activity directed at the physical, emotional, moral, intellectual, and spiritual care of the offspring (Pruss 2013).

Romantic love thus produces the deepest possible union at all levels of the person. However, the depth of the union that is exhibited in romantic love is not temporally limited. Romantic love seeks its consummation, but also seeks a union that is extendable across time, with a way to extend this union is through an act of commitment being made by the persons striving to achieve the goal of reproduction (Pruss 2013). However, this reproductive striving would then, in turn, continue in the lovers’ mutual contribution in caring and educating their offspring. Thus, as Pruss (2013, p. 169) notes, ‘a joint commitment to reproducing and raising children when and if that becomes possible, morally licit, and prudent can bind them together, in a way that extends the biological union interpersonally and in time’. Therefore, despite the temporal nature of sexual union, the presence of a normative commitment made by the persons in the relationship can enable the momentary sexual union to be temporally extended, resulting in the union as one body being able, to some extent, persist outside of the sexual act (Pruss 2013).

In summary, romantic love is thus distinguishable from all other forms of love through the type of real union that is appropriate to it: sexual union. This sexual union, in an analogous manner to biological union, is a functional, organic union of the lover and their beloved as one body. In romantic love, the lovers are thus one body through a common physical striving for reproduction, which produces the deepest union possible, with the further possibility of a normative commitment being made to one another, which provides a temporal extension of this organic union through time. We can now focus our attention on part (C) of our conceptual analysis, which is that of analysis of the manner in which God would seek to fulfil the duty to agapê.

God’s Fulfilment of the Duty to Agapê: it is always the best possible action for God to fulfil his obligations and duties where there are any. Love, construed as agapê, presents God with the duty to love everyone, which would thus include a love of himself—God would exemplify self-love. Self-love, as with all other forms of agapê, has three intertwined aspects: appreciation, benevolence, and a striving for union—a formal union and a real union. As previously noted, for the formal and/or real union aspect of agapê to be exhibited in a self-love context, an individual will need to be ‘divided against themselves’ and thus lack internal integration in their mind—resulting in them being doubled-minded—and an internal integration in the will—resulting in them willing incompatible things or failing to will what they desire to will. In this ‘internal disintegration’ case, a striving for a formal union of intellect and will, and a real union with oneself, will indeed be possible, resulting in the fulfilment of the duty to show agapê to oneself being realised. However, this division against oneself, which counterintuitively enables one to exhibit self-love, is not a possibility in a theistic case. As being omnipotent, God would not lack either integration in the mind—he would know only of all true propositions and thus not be double-minded—or, in the will—he would only will what there is reason to will and thus would not will incompatible things. Thus, God cannot lack internal integration or be divided against himself, which means that he cannot fulfil his duty of exhibiting self-love. However, as God must (in some manner) fulfil this duty in order to be perfectly good, he must find another means for this duty to be fulfilled. That is, more specifically, God must fulfill this specific duty of self-love, if possible, or perform an equally best action, if the former is not possible, in order for him to be perfectly good—as for God to not fulfill this specific duty, or one that is similar to it (or has the same intrinsic value as it), would be for him to transgress the agapeic duty to love all, which would be a bad action that a perfectly good being cannot perform. Yet, as God cannot fulfill the former duty—as he cannot lack internal integration or be divided against himself—he must fulfill the latter duty of performing an equally best action—which is plausibly an action that is analogous to (ordinary) self-love. Now, specifically one way in which this this can be done—that is of God performing an equally best action—is that of God ‘dividing himself’ (in an analogical fashion) by causing to exist a duplicate of himself—an entity that shares the same intrinsic properties as him and is thus distinguishable by extrinsic properties alone (Langton and Lewis 1998, pp. 336–37). And by doing this, God can thus exhibit ek-static self-love—which we can take to be a sub-form of self-love36 —by enabling the required formal union to take part between two (extrinsically distinct) duplicated objects: God, who is divine person one,37 and divine person two (hereafter, d₂), each of whom exhibits ‘self-love’ by appreciating and willing the good for themselves and striving for a formal union by the integration of their intellect and wills. Thus, it would be a unique best possible action—an action that a perfectly good being must perform—for God to everlastingly cause to exist d₂ in order for his perfect goodness to be manifested by fulling his duty to ‘self-love’—though in an ek-static manner.

Yet, the perfect goodness of God would require him to do more in the agapeic relationship that he is in. That is, the unitive aspect of agapê does not only include a striving for formal union, but also a striving for a real union between lovers. As we saw, the achievement of a real union is not always possible within a loving relationship due to, for example, the possible physical distance between lovers. However, as there would not be any possible impediment to the achievement of a real union between God and d₂, the striving for this type of union will be realised.

Furthermore, as previously noted, the depth of real union is definitive of the form of agapê—a romantic, filial or fraternal form of agapê—that is present within a relationship, with the deepest possible union—a one body union—being the unique distinguishing characteristic of romantic love. Given the duty to show agapê to one another, the need to express a form of agapê that is appropriate for perfect individuals, and the goodness of instantiating the deepest possible union, one has good reason to believe that God and d₂ will exemplify a romantic form of agapê. However, being non-embodied beings, they will participate in a particular sub-form of a romantic relationship, which we can term a perichoretic relationship.38 Specifically, the perichoretic relation between God and d₂, would be one that they seek to consummate through achieving a union as ‘one being’.39 However, this union as one being is not a metaphysical fusing of God and d₂; rather, in a similar manner to the union as ‘one body’ that is present within the human sub-form of a romantic relationship, there will simply be a functional co-ordination and mutual striving by them toward the fulfilment of a common goal. God and d₂ are thus interconnected by their coordinated striving for a common purpose. However, if the union between God and d₂ is to be a good and significant, which would be required by their perfect goodness, then the goal that is striven for by them will also need to be valuable and of proportionate significance. So, as in the human case, the goal of generation would be highly valuable and of proportionate significance for two reasons: firstly, as this will be the ‘generation’ of another divine person, which would plausibly add a significant amount of value to the world in which he exists in.40 Secondly, the goal of generation will also allow the union and activity within the perichoretic relationship between God and d₂ to be richly layered: a ‘lower-level’ union and activity that is ontologically directed at the generation of another divine person and a ‘higher-level’ union and activity that is produced by the lower-level activity,41 which is directed at a further co-operation in forwarding the intellectual, moral, emotional, and spiritual goals of that additional divine person.42 Thus, there is the common striving for a common purpose: an ontological striving for generation, which results in an ontological union between God and d₂ as ‘one being’—namely, the sharing of the same nature (and will). The romantic, perichoretic love present in the relationship between God and d₂, which would be grounded upon the deepest possible union at all levels of them, will be realised in the fulfilment of their striving for the generation of an (extrinsically distinct) duplicated object: divine person three (hereafter, d₃). Like the causation of d₂, God, in co-operation with d₂, must everlastingly cause to exist d₃ in order for his perfect goodness to be manifested. This would be that of him performing the unique best possible action of consummating his perichoretic relationship with d₂ by achieving the deepest possible real union—an ontological union as one being. And the extendibility of this real, ontological union would be possible by God and d₂ committing themselves towards the fulfilment of this generative striving and the mutual contribution in further cooperating in forwarding the goals of d₃. There would thus be three divine persons: God, d₂ and d₃.

Why Three Objection?: against this conclusion, however, one could raise the objection, which we can term the Why Three Objection?, of why the ontological unity of God and d₂—that is directed towards the generation of d₃— should only stop with him? Wouldn’t the real union between God and d₂ be further deepened by them striving for the generation of more divine persons? In short, why should this process stop at three? However, as Swinburne (2018) notes in a related context,43 if this objection was correct, then no matter how many divine persons that God and d₂ co-operatively strove to generate, it would always still be better if they continue striving to bring about more. Yet, as was explained above, in the case when there is an infinite series of incompatible possible good actions available to some agent—with each action within this ordered series being better than the previous action—it is not logically possible for an agent to perform the best action, as there is no best action. Thus, God and d₂ would each be perfectly good in this type of situation if they perform any one of the incompatible good actions within that series. Therefore, in applying this to the situation at hand, given that the bringing about of two other divine persons by God is incompatible with the alternative action of bringing about three divine persons, the perfect goodness of God would be satisfied by his bringing about only two additional divine persons—one in order to manifest self-love and another to consummate his loving relationship with the d₂. Thus, it is not required for God to bring about any additional divine persons as a result of the striving for generation with d₂ (which is the goal of their perichoretic relationship) in order for him to be perfectly good. Hence, any additional divine person that is generated by the co-operative striving of God and d₂ would thus not be produced by a necessary act of their essence—an inevitable consequence of them being perfectly good. Rather, any particular number of divine persons over that of a third divine person—d₃—would be produced by a creative act of will, given that there will be no overriding reason to choose any particular number of divine persons within the infinite series of incompatible best possible actions, and thus any particular number of divine persons that are in fact produced by the generative striving of God and d₂ would stem from a free-will choice of them.44 Yet, the problem with this, as Swinburne (2018, pp. 12–13) notes, would be that any additional divine person would thus not exist necessarily in the same manner that d₂ and d₃ exist—which is that of their existence ultimately being a necessary consequence of the existence of a necessary being—God—and thus this additional divine person would not be divine. Therefore, there cannot be any additional divine persons (over and above that of d₃) that are produced by the co-operative striving for generation which consummates the perichoretic relationship of God and d₂—necessarily there can only be three divine persons: God, d₂ and d₃.

Taking all of these things into account, if there exists a God, defined as an essentially, everlastingly omnipotent person (and thus a perfectly good person), and love is revealed as a duty-imposing, multi-formed agapê—where this love would include the aspects of appreciating the beloved, willing the good for the beloved and seeking a formal and real union with them—then we can obtain a priori knowledge that necessarily this God would be the Father (i.e., be a divine person who inevitably causes to exist two other divine persons). In other words, and assuming moderate essentialism, it would be an essential property of God to be the Father, given the fact that his perfect goodness would require him to everlastingly cause to exist another divine person: d₂, a duplicate of him, in order for him to exhibit the formal union aspect of agapê within a self-love context, and, therefore, fulfil his duty to love everyone. However, as agapê seeks consummation through real union, this divine person, God, would thus seek to consummate his love for d₂ by establishing the deepest possible real union with him: an ontological union as ‘one being’. Thus, the relation between God and d₂ would be that of a romantic form of love: perichoretic love, which is consummated by the striving for an ontological union as one being, and realised by their functional co-ordination to fulfil a significantly valuable common goal: the generation of another divine, duplicated person—d₃. Yet, this striving for generation by God and d₂ would not lead them to generate another divine person over and above that of d₃, given the need for a divine person to be generated by an act of essence, rather than as an act of the will, in order for them to exist as necessarily as any other divine person. So, the love that God has for himself, leading to an everlasting generation of the d₂, and the desire for real union that God has for d₂, which would be achieved by a personally integrated generative striving that leads to the everlasting generation of d₃, provides a good basis for taking the conditional statement of (1) to be a necessary truth, knowledge of which is obtainable a priori.

We thus have completed our a priori conceptual analysis of (1), and with our a posteriori empirical investigation of (2) completed as well, we can now proceed to the conclusion of the argument.

3.3. Necessary A Posteriori: God Is the Father

At the centre of premise (3) is the following necessary a posteriori conclusion that is derivable from our previous a priori conceptual analysis and the empirical discoveries that have been made:

Necessary A Posteriori Statement

(3) (R): Necessarily, God is the Father

Premise (3) is the necessary conclusion reached at the end of the ERNA, and this conclusion is knowable a posteriori. Specifically, at the centre of the A Posteriori Argument is the claim that the property of being the Father (i.e., being the divine person who causes to exist two other divine persons) is an essential property of God. As an essential property, we can thus know by a priori conceptual analysis that (1) is a necessary statement, if true. Yet, we cannot obtain knowledge concerning the truth-value of this statement via this same a priori conceptual analysis. Rather, it is by an a posteriori empirical investigation concerning the truth-value of the antecedent of the conditional of (1), which is the contingent a posteriori statement of (2), which allows us to deduce the necessary a posteriori statement above of (3). God being the Father is thus a necessary a posteriori statement in the sense that it is both necessarily true—there is no possibility that God could not have exemplified this property (by not inevitably causing to exist two other divine persons), and it is knowable only a posteriori—on the basis of some form of empirical evidence.

In further precisifying the conclusion reached here, we can assume the previously adduced distinction between metaphysically and epistemically possible world-states, and re-state that the fact that one cannot know a priori that the above conclusion is true means that one cannot know, independent of experience, that a specific world-state in which this proposition is false is not in fact instantiated—it is thus an epistemically possible-world state. However, despite this state of affairs, what one can know a priori is that (1) is a necessary truth, and thus any world-state in which it is true that God exists and he acts in such a way as to reveal that love is a duty-imposing, multi-formed agapê, then there is no world-state in which it is false that ‘God is the Father’ could have been instantiated. In other words, when one discovers through empirical investigation that it is true that God exists and he acts in such a way as to reveal the nature of love as a duty-imposing, multi-formed agapê, then one also learns a posteriori that the epistemically possible world-states in which he is not the Father are in fact metaphysically impossible. The empirical evidence supporting the truth of the antecedent of the conditional statement of (2) is required for knowledge of the necessary truth of the statement that ‘God is the Father’, through it serving as evidence that helps us to rule out the metaphysically impossible, yet epistemically possible, world-states in which that further statement is false. We can illustrate this as follows through Figure 2 (with all the same representations as before, except for P∧Q representing the statement ‘God exists and love is revealed as a duty-imposing, multi-formed agapê’ is true, R representing the statement ‘God is the Father’ is true, and ~R representing the statement ‘God is the Father’ is false):

Thus, as before, what we have here is a set of epistemically possible world-states which includes a system of metaphysical possibility, with a designated ‘actual’ world state and further space for related world-states. Once one reaches the conclusion that the epistemically possible world-state that includes the truth of (2) is to be designated as the instantiated ‘actual’ world-state, then any incompatible epistemically possible world-states relative to it, are to be designated as metaphysically impossible world-states—which is a result of our a posteriori empirical investigation. So, the remaining metaphysically possible world-states are only those which are compatible with (2) (such as possible world states where the statements ‘God is the Father and has not created anything’ or, ‘God is the Father and did not send d₂ to planet Earth’ are true).45 Thus, even though (1) can be known a priori, any knowledge concerning its truth-value and our ability to discern what are, in fact, the metaphysically possible world-states concerning God’s nature is only obtainable a posteriori. Thus, in re-stating the conclusion reached by the A Posteriori Argument, God is the Father (and thus there are three divine persons), which we take to be necessary—true in every metaphysically possible world-state—and a posteriori—it is the result of, and grounded upon, empirical investigation. There is thus no Intuition Objection that can be raised against this type of Love Argument, as the nature of love that played a part in this argument is not intuitively-based but is one that is grounded in objective reality—it is taken to be revealed by God, and, therefore, all individuals have an opportunity to access this revelation and thus reach the same conclusion themselves.

4. Prospects: Further Benefits of the A Posteriori Argument

Alongside the ability for the A Posteriori Argument to ward off the Intuition Objection, the argument can also successfully enable one to obtain knowledge concerning the necessary truth of the existence of the Trinity without, however, also succumbing to two further important objections that can be raised against the A Priori Argument: the Dispositional Objection and the Revelation Objection. And so, given this, the prospects for the A Posteriori seem to be bright for future Trinitarian theorising. It will be helpful to now briefly see why these objections provide a good reason for one to favour the A Posterior Argument over that of the A Priori Argument.

The Dispositional Objection: is a specific objection against the concept of love that is utilised by the A Priori Argument. Specifically, the Dispositional Objection, which has been expressed most recently in the work of Dale Tuggy (2015, 2021), goes as follows: God being a divine person would indeed require him to be a loving person (i.e., possess a specific intrinsic disposition to be loving). However, according to the Dispositional Objector, there is no further requirement for him to be in a loving relationship with two other divine persons, as being perfectly loving (and thus perfectly good) is simply a dispositional quality of God that is not required to be exercised (in and through a loving relationship with another). Thus, as Tuggy (2015) notes, there is no specific deficiency in God if he is not in a loving relationship, even if being so is a great good in itself—in the same manner, that there is no deficiency in God if he didn’t create anything, despite the great good of doing so. Tuggy (2015, p. 137) expresses this point clearly in writing that:

God would nonetheless, sans creation, be perfect. Again, it’s a great good to be the source of a gorgeous, amazing cosmos, teeming with life, which one beholds with satisfaction as “very good”. But we don’t want to say that God would be imperfect if he’d made nothing...…were God to have “missed out on something high and wonderful”, it doesn’t seem to follow that there would be “a deficiency in God”. Not all goods, not even all great goods, are such that their absence would render one imperfect. Some goods one doesn’t need in order to be perfect.

Therefore, God would still be perfect if he did not utilise his capability to love another divine person prior to creation, in the same way that he would be perfectly good even if he did not utilise his capability to create. Thus, we do not have good reason to believe that God being perfectly loving requires him to inevitably bring about two other divine persons (i.e., be the Father).

This is indeed a successful objection against the A Priori Argument; however, when the Love Argument is reformulated as an A Posteriori Argument, which was done above, this objection does not apply. This is because the objection is assuming that love is to be defined as a disposition that needn’t always be exercised (if possible). However, the A Posteriori Argument fixes the definition of love as that of agapê, which, as noted previously, is not a disposition, but one that is constituted by action. Thus, given that the a posteriori basis of this argument takes love to have been revealed as agapê, God cannot be perfectly loving if he is not exercising his will in a loving way—if he is not performing the action of love. Additionally, as our a posteriori basis also takes there to be a duty to show agapê to every individual, God must be in a loving relationship with two other divine persons in order for him the exemplify (ek-static) self-love and for him to consummate the perichoretic relationship that he is in with d₂ by establishing the deepest union possible. Thus, the analogy between God being able to love and being able to create is indeed not a good one, given the a posteriori basis of the argument and the empirical discovery which takes love to be an action—agapê—and the duty to perform this action presenting God with an overriding action that he must perform, given his perfect goodness. Whereas there is no obvious, revealed (or, empirically grounded) reason why one should take there to be a requirement (or, more specifically, an overriding reason) for God to perform the action of creating, even though it is certainly a good thing for God to do so. Therefore, it is clear to see that the Dispositional Objection is not applicable to the A Posteriori Argument. Turning our attention now to the Revelation Objection.

The Revelation Objection: is an objection raised against the philosophical methodology that is utilised by the A Priori Argument. More precisely, this objection, at a more general level, is found within the work of St. Thomas Aquinas and the teaching of the Roman Catholic Church, which we can take to be paradigm examples of the traditional mainstream position. Specifically, the traditional position within Church history has been that the Trinity is not a teaching that is accessible solely on the basis of reason—it is not a teaching that can be known in a way that is divorced from the revelation of God. That is, as Aquinas writes, ‘It is impossible to attain to the knowledge of the Trinity by natural reason…Whoever, then, tries to prove the trinity of persons by natural reason, derogates from faith in two ways’ (Aquinas 1948, Summa Theologiae I, q. 32, a.1). Aquinas, as with others, sees that the Trinity is not a teaching that can purely be reasoned to. And in support of this, the Catechism of the Catholic Church states, ‘The Trinity is a mystery of faith in the strict sense, one of the “mysteries that are hidden in God, which can never be known unless they are revealed by God”‘ (Catholic Church 1997, CCC 237). According to this, the Trinity is thus a ‘mystery of faith’, which indicates that one cannot acquire knowledge of the Trinity from a purely a priori conceptual analysis of God’s nature. Instead, again, one can only obtain knowledge of this teaching by it being revealed by God. So, it is quite clear that Aquinas and the teaching of the Roman Catholic Church, which we took to be the paradigm examples of the traditional mainstream position, is in direct contention to the A Priori Argument, which proceeds to establish the necessary truth of the Trinity on the basis of a conceptual analysis of God’s nature alone. The A Priori Argument thus does not fit with the common and traditional position of the Trinity being a revealed doctrine. The Revelation Objector would thus urge one to reject the philosophical methodology that is utilised by this argument and the conclusion that is reached by it.

The Revelation Objection, which is supported by the weight of tradition, thus provides one with a good reason to favour the A Posteriori Argument over that of the A Priori Argument. Specifically, why this is so, is because of the philosophical methodology that is utilised by the A Posteriori Argument being grounded upon empirical, revealed reality. That is, the A Posteriori Argument does not reach the conclusion that the existence of the Trinity is a necessary that is discernible by reason alone. Instead, it reaches this conclusion concerning the necessity of the Trinity on the basis of a dual epistemological path: an a priori analysis and an empirical investigation. More precisely, the statement that ‘God is the Father’ is knowable on the basis of an a priori conceptual analysis of the concept of love: agapê (and God’s duty fulfilment), and an a posteriori empirical investigation of the evidence in support of the existence of God and the nature of the duty-imposing, multi-formed agapê that he has revealed. The A Posteriori Argument, unlike that of the A Priori Argument, thus allows the Trinity to be grounded upon the foundation of (a priori) reason and (a posteriori) revelation, which is much more in line with that of the traditional position of the doctrine being knowable via God’s special acts of revelation (which are in line with reason). Therefore, in a similar manner to the Dispositional Objection, it is also clear to see that the Revelation Objection is also not applicable to the A Posteriori Argument.

The A Posteriori Argument thus seems to not be afflicted by some of the more important objections that can be raised against the A Priori Argument (i.e., the Intuition Objection, the Dispositional Objection and the Revelation Objection), and thus the former type of Love Argument should be favoured over that of the latter type in enabling one to obtain knowledge concerning the necessary truth of the doctrine of the Trinity.

5. Conclusions

In conclusion, a new version of the argument from love for the Trinity has been proposed, which utilises the notion of the necessary a posteriori and the concept of love as agapê. The utilisation of this philosophical notion and concept allowed us to ward off the Intuition Objection (and the Dispositional and Revelation Objections) by re-construing the ‘Love Argument’ as a kind (or category) of arguments, and then taking the A Posteriori Argument to be a new member of it. This A Posteriori Argument posits that God is necessarily the Father—the divine person who inevitably brings about two other divine persons—if it is true that God exists and love is a duty-imposing agapê. However, to discover whether this conditional is, in fact, true, an empirical investigation must be performed. This empirical investigation was (plausibly) taken to be a success, and so our conclusion is that God is indeed the Father—the Trinity is necessary. However, unlike the A Priori Argument, the truth of this matter is not epistemically accessible from a purely a priori standpoint. Rather, it is an instance of the necessary a posteriori, which does not weaken the Love Argument but, in fact, strengthens it by building it upon an evidentially secure foundation.