The Eternal Relations of Origin, Causality, and Implications for Models of God

Abstract

The classical doctrine of the eternal relations or origin (ERO) claims that these relations are (1) atemporal and (2) causal. In this paper, I investigate the casual nature of the ERO, highlighting that the patristic and medieval Christian thinkers who developed this doctrine understood causality in terms of Aristotle’s efficient causality, highlighting that these are casual acts that produce an effect. I then provide an analysis of some of the major theories of efficient causation on offer in contemporary metaphysics to see which theory best comports with how the ancient and medieval Christian thinkers understood the efficient–causal aspect of the ERO, concluding that a powers theory of causation seems to work best. I conclude by discussing the implications the classical doctrine of the ERO has for models of God, arguing that they are compatible only with classical theism and neoclassical theism.

1. Introduction

Throughout the early church, patristic theologians understood the trinitarian eternal relations of origin (ERO), i.e., the eternal processions, in terms of causality. When scripture teaches that the Father begets, or generates, the Son, the patristic fathers understood this to mean that the Father, in his timeless eternity, causes the being and existence of the Son. The same is the case with the doctrinal claim that the Father [with or through the Son] spirates the Spirit. Theologians who explicitly affirm this causal aspect of the processions include Origen, Basil of Caesarea, Gregory of Nazianzus, and Gregory of Nyssa, and this causal understanding of the processions is most likely in view in the processional teachings of the Niceno-Constantinopolitan Creed.

In what follows, I conduct an analytic–theological investigation of this causal understanding of the ERO. In particular, I investigate various understandings of “cause”, both ancient and contemporary, and I articulate what view of causation was in mind when the patristics claimed that the Father causes the Son’s and the Spirit’s being. I argue that the patristics had efficient causation in mind when they articulated this doctrine. I then articulate how we should best understand these causal relations today if we are to maintain this aspect of the classical doctrine of the ERO. In so doing, I consider questions such as whether or not causes must temporally precede their effects and whether or not the notion of atemporal, or timeless, causation is metaphysically possible. I conclude by considering implications for these causal relations of origin for models of God, namely classical theisms and neoclassical theisms.

2. God Causing God: The Eternal Relations of Origin

Part and parcel of the pro-Nicene doctrine of the Trinity, which became the orthodox doctrine of the Trinity, is the ERO. According to the ERO, the Father begets, or generates, the Son, and the Father, with or through the Son, spirates the Spirit. According to the text of the Niceno-Constantinopolitan Creed, “We believe in the Lord, Jesus Christ, the only-begotten Son of God, eternally begotten of the Father, God from God, Light from Light, true God from true God, begotten, not made, of one Being with the Father. … We believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father [and/through the Son], who with the Father and the Son is worshiped and glorified” (BCP 2019, p. 127). Such the church has confessed since the Council of Constantinople in 381 AD—and many Christians before that. Though this doctrine was not enshrined as Christian orthodoxy in the text of an ecumenical creed until the 4th century, the doctrine of the eternal relations of origin (DERO) was affirmed and taught by Christian theologians since the early 3rd century when Origen of Alexandria articulated an early version of the doctrine known now as the eternal generation of the Son. Though the Father’s generation of the Son was taught as early as the mid-2nd century by thinkers such as Justin Martyr, it was not cashed out in terms of eternal generation until Origen’s treatments several decades later.

Though the spiration of the Spirit was often presumed by many of the early-mid patristic fathers, it was seldom discussed and/or fleshed out due to the contextual nature of the doctrinal debates of the time, which focused on the full deity of the Son. The spiration of the Holy Spirit received further treatment in the mid-late 4th century in response to the attacks on the deity of the Spirit by the pneumatomachi and the Eunomians. According to the doctrine of the eternal spiration of the Spirit, the Father with/through the Son spirates the Spirit. This doctrine sometimes is defined as the Spirit’s proceeding from the Father and/through the Son. With the eternal spriation of the Spirit in place, the DERO was enshrined as orthodox Christian teaching at the Council of Constantinople in 381.1

Throughout the bulk of the history of Christian doctrine, the DERO has been central to the church’s trinitarian teaching. Due to the patristic and medieval fathers’ commitments to the doctrine of divine simplicity (DDS), the ERO offered the fathers a way to differentiate the divine persons without introducing composition into the Godhead. It was via the ERO, confessed the fathers, that the single concrete divine nature was communicated from the Father to the Son and the Spirit. The Father related to the Son via the relation of paternity, the Son related to the Father via the relation of filiation, and the Spirit related to the Father and/through the Son via the relation of procession. The relation of paternity is understood as the way/mode the divine nature subsists as the Father, the relation of filiation is understood as the way/mode the divine nature subsists as the Son, and the relation of procession is understood as the way/mode the divine nature subsists as the Spirit.2 These distinct relations were described as the persons’ notional properties, and these were considered to be the only distinguishing features amongst the divine persons. So, for the patristics and the medievals, the only thing that distinguished the Father, the Son, and the Spirit from one another were these notional properties, their unique ERO. As we can see, there thus was no Trinity, for these thinkers, apart from the ERO.

But the patristic and medieval fathers did not stop simply at describing the ERO as that which constitutes and differentiates the persons. Rather, they had a good bit to say about the very nature of these relations. Specifically, the patristic and medieval theologians were near unanimous in describing the ERO as atemporal causal relations. Though discussions of the atemporal feature of the ERO can be traced all the way back to the writings of Justin Martyr wherein he discussed the Father’s generation of the Son, the causal feature of the ERO doesn’t receive much attention, to my knowledge, until the 4th century.3 The primary exemplars for using such language of the ERO include Basil of Caesarea, Gregory of Nazianzus, Gregory of Nyssa, and Hilary of Poitiers. Let’s take a moment to consider some of the passages wherein they use this language.

“Since the Son’s principle comes from the Father, it is in this sense that the Father is greater, as cause and principle. For this reason too the Lord said the following: The Father is greater than I [Jn 14.28], clearly meaning insofar as he is Father. But what else does ‘Father’ signify, other than that he is the cause and the principle of the one begotten from him”

(Basil of Caesarea 2011, p. 127)?

“Because they [the Son and Spirit] are from him, though not after him. ‘Being unoriginate’ necessarily implies ‘being eternal,’ but ‘being eternal’ does not entail ‘being unoriginated,’ so long as the Father is referred to as origin. So because they have a cause they are not unoriginated. But clearly a cause is not necessarily [temporally] prior to its effects—the Sun is not [temporally] prior to its light. Because time is not involved, they are to that extent unoriginated—even if you do scare simple souls with the bogey-word; for the sources of time are not subject to time”

(Gregory of Nazianzus 2002, p. 71; italics mine).

“If, however, any one cavils at our argument, on the ground that by not admitting the difference of nature it leads to a mixture and confusion of the Persons, we shall make to such a charge this answer;—that while we confess the invariable character of the nature, we do not deny the difference in respect of cause, and that which is caused, by which alone we apprehend that one Person is distinguished from another;—by our belief, that is, that one is the Cause, and another is of the Cause we recognize another distinction. For one is directly from the first Cause, and another by that which is directly from the first Cause; so that the attribute of being Only-begotten abides without doubt in the son, and the interposition of the Son, while it guards His attribute of being Only-begotten, does not shut out the Spirit from His relation by way of nature to the Father.”

But in speaking of ‘cause,’ and ‘of the cause,’ we do not by these words denote nature (for no one would give the same definition of ‘cause’ and of ‘nature’), but we indicate the difference in manner of existence. For when we say that one is ‘caused,’ and that the other is ‘without cause,’ we do not divide the nature by the word ‘cause,’ but only indicate the fact that the Son does not exist without generation, nor the Father by generation: but we must needs in the first place believe that something exists, and then scrutinize the manner of existence of the object of our belief: thus the question of existence is one, and that of the mode of existence is another. To say that anything exists without generation sets forth the mode of its existence, but what exists is not indicated by this phrase. … When, therefore, we acknowledge such a distinction in the case of the Holy Trinity, as to believe that one Person is the Cause, and another is of the Cause, we can no longer be accused of confounding the definition of the Persons by the community of nature”

(Gregory of Nyssa 1885, p. 336; italics mine).

“Assuredly, it cannot be said that to have come forth from God is the same as to have come, for He refers to both of them: ‘For 1 came forth from God and have come.’ And He shows the meaning of ‘1 came forth from God’ and ‘1 have come’ by adding at once: ‘for neither have 1 come of myself but he sent me.’ He taught that He was not the cause of His own origin when He says: ‘for neither have I come of myself,’ and when He again testifies that He came forth from the Father and was sent by Him. But, when He declared that He must be loved by those who said that God was their Father, because He came forth from God, He taught that the reason for loving Him arose from His birth.”

(Hilary of Poitiers 1899, The Fathers of the Church, p. 200).

“And if we say that the Father is the origin of the Son and greater than him, we do not imply that he precedes the Son in time or in nature, for ‘through him he created the aeons.’ Nor do we imply anything else except causality, which is to say that the Son was begotten of the Father, not that the Father was begotten of the Son, and that the Father is the cause of the Son by nature, just as we do not say that a flame comes from light, but rather that light comes from a flame. So when we hear that the Father is the source of the Son and greater than him, we should understand this in a causal sense.”

(John of Damascus 2022, p. 77).

As we can see, the language of causality is essential in how these patristic fathers, and Damascene, understood and cashed out the ERO. This language also appears throughout the writings of most of the medieval theologians, including Anselm of Canterbury, Peter Lombard, Richard of St. Victor, and Gregory of Palamas. But one may rightly wonder some of the following questions: “What exactly did these thinkers mean when they described the Father as the cause of the Son and the Spirit? Didn’t the word for cause, aitia, designate a few different kinds of relations in ancient philosophy and theology? Does this entail some kind of subordination of the Son and Spirit to the Father? Don’t causes always temporally precede their effects?” These are all important questions and ones I will be concerned with in what follows.

3. Aitia and Its Uses in Ancient Philosophy and Theology

Aristotle famously distinguished between four kinds of causes in his Physics and Metaphysics, what we now refer to as (1) material causes, (2) formal causes, (3) efficient causes, and (4) final causes. Aristotle defines each of these as follows (Aristotle 1984b, II.3.24–34; cf. Aristotle 1984a, V.1.1–2.32).

Material Cause df. = that out of which a thing comes to be and which persists … e.g., the bronze of the statue, the silver of the bowl, and the genera of which the bronze and the silver are species.

Formal Cause df. = the form or the archetype, i.e., the definition of the essence, and its genera, are called causes (e.g., of the octave the relation of 2:1, and generally number), and the parts in the definition.

Efficient Cause df. = the primary sources of the change or rest; e.g., the man who deliberated is a cause, the father is a cause of the child, and generally what makes of what is made and what changes of what is changed.

Final Cause df. = the sense of end or that for the sake of which a thing is done, e.g., health is the cause of walking about.

Upon reading these definitions, we quickly realize that the ancient understanding of “cause” was much broader than our contemporary philosophical and scientific understandings of the term. More specifically, in contemporary thought, we typically reserve the word “cause” for what Aristotle defines for us as an efficient cause, which is a relation of production. If some thing p efficiently causes some thing q, then p produces, or brings about, q. However, aitia as Aristotle uses it seems to have the broader notion of explanation when he uses the generic cause rather than merely efficient causation.4 As a result, Aristotle describes these four kinds of causes as four kinds of explanations of a thing’s being. Since, on Aristotle’s metaphysical schema, things are composed of form and matter, they have both a formal and material cause. Due to the significance of telos in Aristotle’s philosophy, it also is no surprise that he included a thing’s purpose as part of its aitia. And lastly, that which produces, or brings about, some thing is part and parcel of its aitia as well.

The patristic and medieval theologians who wrote on the ERO were almost certainly aware of Aristotle’s taxonomy of causes—we know the medievals were due to the renaissance of Aristotelian philosophy during the medieval years. The question we are interested in is this: when patristic and medieval theologians, such as the Cappadocians, Hilary, and Damascene, referred to the Father as the aitia of the Son and the Spirit, in what sense did they mean this? In other words, what kind of aitia did they most likely have in mind? Since all of these early and medieval thinkers affirmed the DDS, then we can say with a fair degree of confidence that they did not have material and formal causes in mind. Not only is God a nonphysical substance, but he is devoid of any and all composition, including form and matter. Thus, there are no formal or material principles in God. Considering that the casual relations in question are generation and spiration, it would seem odd for us to think that the fathers had final causation in mind. Surely they did not mean only to say that the Father is the purpose, or telos, of the Son when they claimed that the Father eternally begets the Son. No, it seems most assuredly that these classical Christian thinkers have efficient causation in mind. When they claimed that the Father begets the Son and that he, with/through the Son, spirates the Spirit, they intended to say that he produces the Son and the Spirit.

However, the fathers had a very qualified sense of production in mind when they claimed that the Father is the efficient cause of the Son. As we saw in Aristotle’s definition, an efficient cause is that which brings about a change or rest. Since God is immutable, that is, he undergoes no intrinsic or extrinsic changes, the Father cannot be said to bring about a change or rest in his production of the Son. This also follows from the atemporal feature of the ERO: since all three divine persons and the ERO are atemporal, then neither the Son nor the Spirit ever begin or cease to exist, nor does the Father’s causal act of production. Rather, the Father timelessly produces the Son and Spirit.

Now, some may wonder if efficient causation is really what the patristic and medieval fathers hand in mind when they described the ERO in terms of aitia. As I’ve already pointed out, it seems unlikely that they would have had material, formal, or final causes in mind, based on their other commitments concerning the divine attributes. But if this suggestion is unsatisfying, then let’s look back to the quoted excerpts that I provided earlier. Nazianzen, in particular, uses the sun’s causation of its light as an analogy of the Father’s generation of the Son. The sun produces its light; it is not the form of the light, the material of the light, nor the telos of the light. It is the proper cause of the light. Hilary refers to the Father’s generation of the Son as the Father’s being the cause of origin of the Son. Likewise, Damascene uses as an analogy of how a flame produces its light for the Father’s generation of the Son: “just as we do not say that a flame comes from light, but rather that light comes from a flame.” Not only did a select group of patristics speak of the ERO in such terms, but so did the bulk of the medieval theologians as well (Paasch 2012). Granted: Thomas Aquinas diverges from the bulk of the tradition and opts to describe the Father as the principle of the Son and Spirit. He writes, “The word principle signifies only that whence another proceeds: since anything whence something proceeds in any way we call a principle; and conversely. As the Father then is the one whence another proceeds it follows that the Father is a principle” (Aquinas 1981, p. 173).5 However, R. T. Mullins rightly notes that Thomas’s preference for “principle” over “causation” seems to be “little more than a word play because he still affirms that the Son is derived from the productivity of the Father” (Mullins 2016a, p. 277 n.50; cf. Paasch 2012). So, even if there is a distinction between Thomas’s view and that of the majority of the rest of the medieval theologians writing on the subject, it seems that it might have been a distinction without a real difference. Nonetheless, it is fair to say that the efficient view of aitia was in mind in the patristic fathers who used this language, as well as the majority of the medieval theologians writing on the ERO.

Now that I have discussed what the majority of the classical tradition affirmed by way of the causal nature of the ERO, I want to turn my attention to some of the work in contemporary philosophy on the metaphysics of efficient causation to see if this work might impact how we understand the DERO today.6 Such a view, to be consistent with this ancient account of causation, would need to affirm that causal relations are metaphysically necessary, entail ontological dependence, are asymmetric, atemporal, and productive. Might it be the case that recent insights into the nature and workings of causation create a problem for cashing out the DERO in causal terms? In particular, I want to focus on how contemporary metaphysicians understand the nature of efficient causation today, noting in particular the relationship of causation to time, asking the following questions: “Must causes necessarily be temporally prior to their effects?” “Is simultaneous causation possible?” And, “Is the notion of an atemporal cause logically coherent?” As responsible theologians, I think it is important that we realize that important conversations concerning metaphysics and causation, and their implications for Christian doctrines, did not cease prior to the Enlightenment. Philosophers, both Christian and non-Christian, have continued to wrestle with issues surrounding the metaphysics of causation, and their work can prove beneficial to us theologians as we continue to refine our doctrines in the context of ever-changing theories about science and the nature of the world in which we live. Not all contemporary philosophy, including analytic philosophy, is beholden to alleged boogeymen, such as nominalism and Humean views on causation, and much of it has a lot to offer us—contrary to what some theologians today would have us believe.

4. Causation in Contemporary Metaphysics

The literature concerning causation has been in somewhat of a state of disarray ever since David Hume called into question our ability to know any law of cause and effect (Garrett 2009, pp. 73–91). Though the ancients and medievals did much by way of discussing the relations of efficient causation, they were not always as clear as we might want them to be concerning the nature and workings of the concept. Sure, they clearly stated that efficient causes are the kinds of causes that produce some effect, but what exactly does this mean? What does it mean for some cause to produce some effect? Since the conceptually revolutionary work of Hume, philosophers have been far from a consensus concerning how to cash out a technical definition of causation. Various theories of causation have flooded the contemporary philosophical literature, and hope for any kind of consensus for a theory seems grim. I therefore think it helpful to briefly discuss some of the more prominent theories of causation on offer today and then evaluate which theory seems to work best with what the ancient and medieval Christian theologians had in mind when they described the ERO in causal terms. Going forward, I will simply use the term “cause” in reference to “efficient cause”, and “causation” in reference to “efficient causation”, since I am not concerned with formal, material, or final causes for the remainder of this essay. Where I do make mention of these, I will use the terms “formal”, “material”, and/or “final” to delineate that particular usage.

I begin with regularity theories of causation, which many philosophers argue was the view of Hume himself. Hume famously argued that all effects are distinct events from their causes. Since we are unable to actually know, e.g., that one billiard ball in motion transferred said motion into another billiard ball, we can at most declare that causation is nothing more than regularities that we experience in our everyday lives (Hume 2007, pp. 20–22). Stathis Psillos lays out the “kernel” of the regularity theory as follows (Psillos 2009, p. 131).

c causes e iff

i.

c is spatiotemporally contiguous to e;

ii.

e succeeds c in time; and

iii.

all events of type C (i.e., events that are like c) are regularly followed by (or are constantly conjoined with) events of type E (i.e., events like e).

Now, it seems likely to me that the ancient and medieval Christian thinkers who affirmed the DERO meant more than what is offered by the regularity theory. While I don’t think said thinkers would have denied that such a notion of regularity is present in cause-effect relations, I also think they would want to say more than this. There is some sort of notion present that, if the Father did not generate the Son, for example, then the Son would not exist. There is at minimum some sort of dependence relation that obtains between the two persons wherein the Son depends on the Father for his being.

The counterfactual theory of causation is a step in the direction just mentioned. David Lewis famously defended this theory (Lewis 1973). A counterfactual is a subjunctive conditional, that is, a conditional that takes on the form “if it were the case that A, then it would be the case that B” (Paul 2009, p. 158). Likewise, if A does not obtain then B does not obtain. Applied to the ERO, if the Father did not cause the Son, then it follows that the Son would not exist. However, Christian thinkers likewise have desired to say that the Father’s cause of the Son [and the Spirit] is necessary. Thus, if the Son [or Spirit] does not exist then neither does the Father. For the medieval emanation theorists, if the Father does not beget the Son then he, by definition is not father. For the medieval relational theorists, the Father begets the Son because he, the Father, just is the relation of paternity. So, if the Father does not beget the Son, then it follows that he is not the relation of paternity, and thus is not Father. In the case the of the ERO, the counterfactual relation seems to be symmetric to some extent. This is not the case in most ordinary instances of cause-effect relations, many, if not most, of which are contingent. If I knock my phone off my desk, then it follows that the law of gravity will result in it hitting the ground. However, it does not follow that, if I do not knock my phone off my desk that my phone will not hit the ground. Perhaps my toddler son reaches up and grabs it and throws it to the floor, as he is prone to do. My point is this: in the case of contingent cause-effect relations, it doesn’t seem to follow, for counterfactual theories, that, if e does not obtain then c did not obtain. Perhaps also c did obtain but some sort of intervention prevented e and resulted in e*. Things seem different, however, wherein a necessary cause brings about a necessary effect.

Now, on the surface, the counterfactual theory seems plausible for a way of articulating the DERO. The only problem I have with it is that it still seems too deflationary, for the same sort of dependence relation seems to obtain for mere grounding relations as well. While all causes are explanations for their effects, it does not follow that all explanations for effects are causes. If we want to maintain a true causal theory of the ERO, then we likely need a different theory of causation than the counterfactual one, one that will provide us with more necessary conditions for some relation to be a causal one. The counterfactual theory, much like the regularity theory, seems stuck only describing what observations are made when a causal relation occurs, and it doesn’t yet tell us what causation is.

The theory of causation that seems best to get at what the patristic and medieval Christian trinitarians have in mind when they describe the Father as the cause of the Son and the Spirit is the causal powers theory. Proponents of this theory, such as George Molnar, prefer to cash out the idea of causal powers along the lines of some object, O, having causal powers to bring about some effect by describing O as having a particular disposition to bring about some effect. Effects are understood as manifestations of O’s exertion of its causal powers. So, on this theory of causation, O causes E just in case that O’s exertion of its causal powers results in the manifestation of E, and if E is manifested as a result of O’s exertion of its causal powers (Mumford 2009). In summary, O has the capacity to exert some power. If O exerts this power, and if E manifests as a result of O exerting this power, then O’s exercised power is a causal power. Thus, O is the cause of E.

This theory of causation seems much more in line with what the ancient and medieval Christian thinkers had in mind when they described the ERO in causal terms, though it does not require that causal relations be metaphysically necessary or atemporal. Though the powers account of causation still isn’t a perfect match up with the ancient view, I think it is still sufficient for my purposes here. Since, on the classical view of God, God is essentially a necessary being that is simple, we can say that, in this case, the ERO, as causal relations, are metaphysically necessary. Since God is atemporal, we can also say that, in this unique case, the causal relations are atemporal. Now, some, namely those advocating a classical–theistic model of God, may worry that the described picture of a powers theory of causation would involve God moving from a state of potentiality into a state of act, and the pro-Nicene theologians would have rejected such an understanding. This is very true, which is why these thinkers did not hesitate to carve out certain caveats for divine causation. Since God is a simple being, existing eternally as pure act, God never changes from a state of passive potency to a state of act. As pure act, the Father eternally causes the Son and Spirit. In terms of the powers theory of causality, the Father eternally exercises causal powers that eternally result in the manifestation of the Son and Spirit. Notice here that both the Father’s exercise of his causal powers and the manifestation, i.e., the effect, of those powers, namely the Son and the Spirit, are both eternal. The Son and the Spirit, being true God of true God, never change from a state of passive potency to a state of act. As pure act, both the Son and Spirit are eternally manifested of the Father’s exercise of his causal powers. The ERO are the eternal exercise of causal powers that eternally manifest eternal effects.

So far, so good. But many contemporary philosophers would question the possibility of an atemporal causation. The patristics and medievals are crystal clear: the ERO are causal, yes, but not in such a way that involves them beginning or ending, undergoing temporal succession, or enjoying temporal location. Those philosophers who would call this into question note that in most instances of causal relations, there is an asymmetric temporal relation between the cause and its effect, namely that the cause is temporally prior to the effect (Price and Weslake 2009, pp. 414–17). Richard Swinburne is but one philosopher who argues that all causes temporally precede their effects, and who provides arguments for explaining what appear to be cases of simultaneous causation and/or retroactive causation (Swinburne 2017).7 But some cases of simultaneous causation seem genuinely possible and unable to be explained away. Suppose some married man M were to die at t₂. M changes from living at t₁ to no longer living at t₂. Absolutely simultaneous with M’s death at t₂, however, M’s wife, W, undergoes a change herself: W, at t₂ becomes a widow. W does not become a widow at t₃, but at t₂, when M died. Yet, it is M’s death that causes W’s being a widow. W manifests the property of being a widow as a result of M’s ceasing to live. M’s death produces the state of affairs of W’s manifesting the property of widowness. As such, M’s death is an efficient cause that is absolutely simultaneous with W’s manifestation of widowness.

While some have attempted to explain such instances away, such attempts have been largely unpersuasive. Now, since on classical theism, God is atemporal, it is not proper to say that the Father’s exercise of casual powers that produce the manifestation of the Son and the Spirit is simultaneous with said production. In order for the cause and the effect to be truly simultaneous, both would have to occur at the same time. But since the God of classical theism, which is the God of the patristic and medieval theologians, is essentially atemporal, then he cannot enjoy temporal location, and so to speak of “simultaneous” causation is technically incorrect. However, I think cases of simultaneous causation can provide some kind of analogy for atemporal causation. Such cases allow us to conceive of how a cause can be simultaneous with its effect, not preceding it. In the case of atemporal causation, some cause c would not [temporally] precede its effect e. While c is not technically “simultaneous” with e [in the sense that both occur at the same time], I think we can still say that c relates to e in a way that is similar to c’s being simultaneous with e. Many of the classical Christian thinkers spoke of God’s atemporal eternity by using the metaphor of “an eternal now”. All of God’s acts, including the ERO, occur in this “eternal now”, which is analogous to simultaneous causation. The typical analogies these thinkers used, such as how a sun is never without its light or how a flame is never without its heat, are intended to convey just this point. So, following these thinkers, it seems to me that if simultaneous causation is possible, or at least conceivable, then atemporal causation is as well.

5. Conclusions: The Eternal Relations of Origin and Models of God

Whether one immediately realizes it or not, the causal nature of the ERO has implications for one’s model of God. By model of God, I follow R. T. Mullins in distinguishing between the concept of God and models of God. The concept of God is that of a perfect being that is the ultimate foundation for all reality. Models of God are distinct ways of cashing out the concept of God and understanding the God–world relation (Mullins 2021, p. 85). Also, following Mullins, I like to classify models of God in terms of the following various categories: classical theism, neoclassical theism, open theism, panentheism, and pantheism. Pantheism is the view that God is identical to the universe; whatever God is, he is not numerically distinct from the universe itself (Nagasawa 2017, pp. 13–15). Panentheism is a little harder to demarcate. Panentheists love to describe their view as something like the following: God cannot exist without the universe, yet God is more than the universe; God is distinct from the universe, yet the universe is “in God;” and the God relates to the universe like a soul relates to a body. However, as Mullins and other have noted, these claims are incredibly vague and don’t tell us much (Mullins 2016b). What does it mean for the physical universe to be located “in” a nonphysical entity? What does it mean for the universe to be the body of God? All that seems truly distinct of panentheism are the following two claims: (1) God is distinct from the universe, and (2) God never exists without the universe, i.e., creation is necessary (Mullins 2016b, pp. 339–42; cf. Mullins 2019).

Open theism claims that God is distinct from the universe, is absolutely free to create, creates the universe ex nihilo, exists a se, is a necessary being, has all of the omni properties, is morally perfect, is rationally perfect, and is temporally eternal. Perhaps the two major distinguishing features of open theism are its requirements for God’s temporal eternity and its understanding of God’s omniscience. Classically, Christian theists mean by omniscience something along the lines of God’s knowing all true propositions, including all tensed propositions and future contingents. Open theism, however, is going to deny that God knows future contingents and future-tensed propositions concerning future contingents (Hasker 1989). Open theists typically tell us a story of either (1) how God has restricted both his omniscience and omnipotence for the sake of entering into a genuinely open relationship with libertarian free creatures, or (2) that it is metaphysically impossible for God to know truths about the future since either (a) future-tensed propositions are all false or (b) future-tensed propositions are neither true nor false. As a result, God cannot have justified true beliefs about future contingents.

Classical theists affirm most of the same divine attributes as do open theists, though they understand God’s omniscience and eternity quite differently. For classical theists, God knows all true propositions, including all future-tensed propositions, and God is atemporally eternal. In addition to God’s necessity, aseity, omni properties, freedom to create, and creation ex nihilo, classical theists also affirm three other distinguishing properties of God: (1) simplicity, (2) immutability, and (3) impassibility. First, the reader should note that all classical theists affirm that God is atemporally eternal, i.e., that God is timeless. Second, classical theists do not simply posit that God has the strongest sort of unity possible in his nature and attributes, but they frequently argue that God is simple, lacking any and all distinct parts whatsoever. God, per simplicity, is not constituted by his various properties; rather, God does not have any distinct properties whatsoever. Whatever properties/attributes that God has are identical with Godself, e.g., God is identical to God’s eternity, God is identical to God’s omnipotence, and thus God’s omnipotence is identical to God’s eternity (Mullins 2021, pp. 87–92). Many classical theists also want to say that God is actus purus and thus has no potentiality whatsoever and that God is pure essence, lacking any and all accidental properties. In virtue of God’s simplicity, he is immutable, i.e., he never undergoes (minimally) any kind of intrinsic change whatsoever, as such would result in his being temporal. In virtue of his immutability, God is impassible, which means that God (1) lacks passions, and (2) is incapable of being acted upon by anything extrinsic to Godself and thus he cannot suffer, lacks literal empathy, and never properly reacts to anything other than himself.

Neoclassical theism is a family of models of God that deny one or more of the four distinguishing divine attributes of classical theism, i.e., simplicity, immutability, impassibility, and atemporal eternity. Unlike open theists, neoclassical theists affirm that God has exhaustive and perfect foreknowledge concerning all future events. Some neoclassical theists, such as Linda Zagzebski, affirm the classical attributes but deny impassibility (Zagzebski 2013, p. 45). Others, such as R. T. Mullins, deny all four of the classical attributes (Mullins 2016c). Neoclassical theism is perhaps home to the greatest diversity of models of God on offer.

As Andrew Hollingsworth has pointed out in a recent paper, whether or not one affirms the classical DERO in the doctrine of the Trinity is going to limit them on their choice model of God (Hollingsworth 2023). Remember, the classical articulation of the doctrine, which is the focus of this paper, is that the ERO are (1) causal relations and (2) atemporal relations. Classical theism, thus, will have no problem affirming this doctrine since it is committed to God’s atemporal eternity, and I have already argued above that atemporal causation is conceivably possible. Thus, classical theism is fully compatible with the classical DERO.

Neoclassical theists who affirm God’s atemporal eternity are also fine to accept the DERO. However, in so doing, they are also going to be committing themselves to God’s immutability and impassibility. If God is temporally eternal, then he will undergo intrinsic change, and if he is capable of undergoing intrinsic change then is possible that he is passible since he would be able to be acted upon by something extrinsic to himself.8 But if God is atemporally eternal, then he will be incapable of undergoing any kind of intrinsic change, since that would entail temporal succession, and he is incapable of being moved by anything extrinsic to himself since that would be a change from one state to another, and all change entails temporal succession. So, neoclassical theists who would affirm God’s atemporal eternity, as well as God’s immutability and impassibility, can affirm the DERO. However, neoclassical theists need not take on divine simplicity. As Hollingsworth demonstrates, one could be a social trinitarian, which is incompatible with divine simplicity, and still affirm the DERO (Hollingsworth 2023, pp. 33–36). But since DERO-affirming social trinitarians cannot accept simplicity, they are struck with only having one model of God open to them, namely, this neoclassical model that denies simplicity and affirms immutability, impassibility, and atemporality.

Since the classical view of the DERO requires God to be timeless, the doctrine will be off-limits to the open theists, panentheists, and pantheists, all of whom affirm a real relation between God and the temporal universe. Whether or not one could affirm the ERO in terms of God being temporally eternal is not the focus of this paper and would take us too far off subject. In a separate paper, I take up the compatibility of divine temporalism and the ERO, arguing that, though such a compatibility is possible, it borders on being unrecognizable to the patristic and medieval Christian thinkers who formulated the DERO in the way that it is understood today (Hollingsworth forthcoming).

In conclusion, the classical DERO requires the Christian theist to affirm either a classical–theist or neoclassical–theist model of God since it entails God’s atemporal eternity.