From one divine person to two or more

1. Personhood is teleologically relational in the sense that a person is the kind of being that necessarily can only be fulfilled in relationships with other persons.

2. Necessarily, any person other than God is a creature.

3. So, if God is a single person, this person necessarily can only be fulfilled in relationships with creatures.

4. If a being only finds its fulfillment in relationships with Fs, then the being’s fulfillment depends on Fs.

5. So, if God is a single person, God’s fulfillment depends on creatures.

6. God’s fulfillment does not depend on creatures.

7. Thus, God is not a single person.

8. thus, if God is a person, God is two or more persons.

(I think most non-Christian monotheists these days will say that God is a single person. But I wonder if it wouldn’t be a better view for them to deny that God is a person at all, and to insist that the centrality of personhood to the understanding of God is a mistaken Christian approach.)

Here is another variant on the argument:

9. Necessarily, a person can only flourish in relationship to another equal person.

10. It is possible that God flourishes.

11. If God is a single person, then it is impossible for there to be another person equal to God.

12. So, God is a single person, it is impossible that God flourishes. (9 and 11)

13. So, God is not a single person. (10 and 12)

14. So, if God is a person, God is two or more persons.

Now, granted, it is a standard view in Christianity that one cannot prove the doctrine of the Trinity by reason. If the arguments above are sound, have I contradicted that view? No, for several reasons. First, the arguments don’t establish that God is three persons. Second, the arguments only establish that if God is a person at all, then God is two or more persons—but a further argument is needed that God is a person at all. (Perhaps perfect being theology can yield that.)

A two-sorted logic and the Trinity

For a while this spring I’ve been thinking about ways of avoiding quaternity views of God.

The problem is that, first,

1. Father ≠ Son, Son ≠ Spirit and Father ≠ Spirit

and, second, we seem to have to choose between the following two options:

A. Father = God, Son = God and Spirit = God, or

B. Father ≠ God, Son ≠ God and Spirit ≠ God.

Add:

2. Father is divine, Son is divine, Spirit is divine, and God is divine.

If we accept (1) and (A), then we have a logical contradiction given classical identity.

If on, other hand, we accept (1), (B) and (2), then there are four that are divine, a quaternity!

A now-standard solution to problems like this is to go for a version of a relative identity theory rather than classical identity. Then the (negated) = in (1) and the = in (A)/(B) are different identity relations (e.g., sameness of person versus sameness of essence).

In this post, I want to consider a somewhat different take on non-classical identity. Suppose we take a variant on two-sorted logic. On a many-sorted logic, bound variables and names come with sorts, and predicates have grammatical restrictions on the sorts of terms that can be their arguments. Usually, the restrictions say for each argument place what sort of term can go in that place. But we can have a more complicated kind of sort restriction.

Suppose, then, we have two sorts: essence and hypostasis, and that = has the classical rules of inference, but has the sort restriction that only terms of the same sort can go on the two sides of =. Suppose that “Father”, “Son” and “Spirit” are of the hypostasis sort, and “God” is of the essence sort. Then we can have (1), but neither (A) nor (B) will express a truth, as both (A) and (B) will be ungrammatical. Even if = has the classical rules of inference, I think there will be no way for us to derive that there are four that are divine. Indeed, in the two-sorted logic, the only way to say “there are four that are divine” is:

3. There are four essences that are divine or there are four hypostases that are divine.

For we cannot mix the essence-variables and hypostasis-variables in an “=” formula.

Interestingly, I think we can have an even stronger non-classical logic of identity while avoiding incoherence and quaternity, though I don’t know if this will appeal to anyone. Make the sort restriction on = be that u = v is grammatical if and only if either u and v are both of the same sort or u is a hypostasis term and v is an essence term. Next, specify that the =-elimination says that from the sentence a = b and a formula ϕ(a), we are allowed to infer ϕ(b), but only if “ϕ(b)” is grammatically correct.

In this stronger logic, we can have all three of (1), (A) and (2), apparently without contradiction. The crucial thing is that from Father=God it is impossible to conclude God=Father, because the latter is ungrammatical. It seems to me to be the Holy Grail of Trinitarian logic to be able to affirm all of (1), (A) and (2).

That said, I don’t like the asymmetric sort restriction on =.

The Trinity and classical identity, again

Let me re-phrase an argument from an earlier post.

Suppose “=” is governed by the classical rules of identity, and G, F, S, and H are names for God, the Father, the Son and the Holy Spirit. Let x ≠ y abbreviate Not(x = y). Let D(x) say that x is divine. There then are three predicates A, B and C such that:

1. A(S) and not A(F)

2. B(H) and not B(S)

3. C(S) and not C(F).

For instance, we can let A(x) say that x is begotten, B(x) say that x is not begotten, and C(x) say that x proceeds.

Then add:

4. Either (a) F = G and S = G and H = G or (b) F ≠ G and S ≠ G and H ≠ G.

5. D(F)

6. D(S)

7. D(H)

8. D(G)

Premise 4 says that the Father, Son and Holy Spirit are on par with respect to being God. Either each is classically identical with God, or classical identity does not apply to any person and God (in which case we explain “The Father is God” as something other than classical identity).

It follows from (1)-(3):

9. F ≠ S and S ≠ H and H ≠ S.

It then follows that (4)(a) is false, so we must have:

10. F ≠ G and S ≠ G and H ≠ G.

It then follows from (9) and (10) and classical identity being an equivalence relation that:

11. ∃w∃x∃y∃z(D(w)∧D(x)∧D(y)∧D(z)∧w≠x∧w≠y∧w≠z∧x≠y∧x≠z∧y≠z).

But (11) is the standard classical logic translation of:

12. There are at least four that are divine.

Heresy!

What are the ways out? We can’t reject (1)-(3). Even if we have some quibbles about the specific examples I chose for A, B and C, every orthodox Trinitarian agrees that for each pair of persons there is something that is truly predicated of one that isn’t truly predicated of the other.

Rejecting any of (5)-(7) is a non-starter: one isn’t a trinitarian if one does not say that the Father is divine, the Son is divine and the Holy Spirit is divine.

That leaves (4) and (8). Start with (8). That seems as uncontroversial as anything about God can be. God is divine!

But here is one way of rejecting (8): reject the presupposition that there is a name, “G”, for God. If we do that, we also end up rejecting (4), of course, but not in a way that threatens the parity of the three persons of the Trinity with respect to being God. I think there are two ways of doing this:

1. Reject the claim that there is a proper name for God as such.

2. Reject the very existence of classical identity.

It is tempting to say that instead of rejecting the very existence of classical identity to God, one can reject its applicability to God. But that can’t be done. It is part of the very concept of classical identity that it applies to everything, that for any name N it is axiomatic that N = N and that it is a theorem that ∀x(x=x).

What about (I)? Surely this is a non-starter. Doesn’t the Christian tradition constantly talk about names of God? Well, yes, but there are names and proper names. What if we say this? There are proper names for the Father, the Son and the Holy Spirit. But there is no proper name for God. Instead, what we have is something like a definite description like “the divine one”.

We still haven’t solved the problem. The normal way to understand definite descriptions is the Russellian way. When you say “The divine one created the world”, you are saying:

13. ∃x(D(x)∧∀y(D(y)→y=x)∧C(x,W)).

That won’t do, however. For (13) leads to a contradiction when it is combined with (1) together with the non-negotiable Trinitarian claim

14. D(F) and D(S)

that the Father is divine and the Son is divine, as well as classical inference rules for identity.

So, what do we do? Here is a suggestion. Let R be an equivalence relation. Then we can have an R-based article “the_R”, and sentences with “the_R” are translated in the Russellian way except with R in place of =.

(Compare how Aquinas makes the distinction between talking in the neuter and talking in the masculine of God, and where when one applies substantives in the neuter, one is talking of the divine essence. One can think of “the_E” as a neuter article, which English doesn’t distinguish from the personal—masculine or feminine—articles, and which Latin lacks altogether, since it lacks articles.)

Thus, “The divine one created the world” translates to:

15. ∃x(D(x)∧∀y(D(y)→yEx)∧C(x,W)).

No contradiction results from (1)-(3) and (14)-(15).

We can call “the divine one” an E-definite description, while “the begetter” is an =-definite description. Aquinas at times in his discussion of the Trinity makes a distinction between substantives used in the neuter and substantives used in the masculine—the masculine is personal in a way that the neuter is impersonal and more suited to when we talk of the divine essence.

Thus, on our present theory, God as such has no proper name, but he does have E-definite descriptions.

Now, what are we to make of the truth value of the following?

16. The Son is identical with the divine one.

If “The Son” is just a proper name and “the divine one” is “the_E divine one”, then (16) is:

17. ∃x(D(x)∧∀y(D(y)→yEx)∧x=S).

And this is false, because it contradicts (5), (6) and (9). So, on the theory under consideration, we have to deny (16). That sounds kind of bad. But perhaps it’s not bad if we realize that “identical” here is classical identity, and we think that classical identity comes to “is the same hypostasis as”, since in the divine case, same hypostasis means same person, and it sounds wrong to say that the Son is the same person as God.

So, I think there is a way of holding on to classical identity while defending the Trinity, but it is costly: we need to say that there is no proper name for God as such and that definite descriptions for God are E-definite descriptions. But denying classical identity is also costly.

A new Thomistic view of the Trinity

I think the historical Aquinas’ solution to how God is one in three persons is a relative identity view that posits two kinds of identity:

1. Individual identity: the lack of a real distinction, where real distinction might come from a difference of matter (as in material substances), a difference of form (as in angels) or an opposition of real relations (as in the Trinity).

2. Sameness of essence: having the numerically same substantial form.

While this is a relative identity account, it has an advantage over more standard relative identity accounts in that it nicely explains our intuitions about absolute identity. For on Aquinas’ solution, as far as we know, except where God is involved, the two identities are co-extensive. For Aquinas (like perhaps Aristotle) believes in individual forms of creatures, so all creatures that are distinct by individual identity have numerically distinct substantial forms, and conversely there are no mere creatures with two substantial forms. Thus when we are not dealing with God, we can afford to be ambiguous between the two kinds of identity, and hence talk as if there was absolute identity. (As far as I know, Thomas never makes this point.)

The point of this post, however, is to offer an alternative version of Aquinas’ two-identities account. The alternative is thoroughly Thomistic, but it’s not what Thomas has. Here it is. We have two kinds of identity. The first is individual identity, as in the historical Aquinas’ solution. The second is:

3. Sameness of esse: having the numerically same esse or act of being.

Just as in the historical Aquinas’ solution, the alternate account has the feature that apart from theological cases, the two kinds of identity are co-extensive. Distinct individual creatures have distinct acts of being, and no creature has two acts of being.

A disadvantage of this view is that “sameness of esse” doesn’t fit quite as well as “sameness of essence” with the Nicene Creed’s “homoousion”. But some things are worth noting. The previous English translation of the Nicene Creed in the Catholic Church actually had “sameness of being”. The word ousia is the abstract form of einai, to be. And in God essence and act of being are the same by divine simplicity. So I think the disadvantage can perhaps be overcome.

An advantage, however, is that sameness of esse seems even more identity-like and unifying than sameness of form. If x and y have the very same act of being, it is hard to deny that there is a real unity between x and y. Here is one way to see the point. On Platonist metaphysics, unlike on Thomastic metaphysics, you and I have sameness of form: we each have the numerically same Form of Humanity. Granted, Platonist metaphysics may be false. But the fact that you and I count as having sameness of form on Platonist metaphysics should make a little less happy about using that as an account of the unity in the Trinity. On the other hand, once we supplement Platonist metaphysics with an act of being, it is clear that you and I will get different acts of being, since each of us can exist without the other doing so.

Moreover, this account may help cast a light on the thorny question of why Aquinas at one point posits a human esse in the incarnate Christ distinct from the divine esse (though elsewhere he denies it). For suppose that there is only one esse in Christ and we accept the sameness-of-being account. Then we would be able say that the Jesus Christ as human is God, since the one and only esse in Jesus Christ, whether as human or as God, is the divine esse, and this we shouldn’t say (and indeed Aquinas denies it). Thus if we accept the sameness of esse account, we get an argument for the two esse view of the Incarnation. Of course, we can turn this around. We might say that the two esse view is false, and hence the sameness of esse account is false.

Trinity, quaternity and naming God

One now-classic solution to some of the challenges of the doctrine of the Trinity is relative identity. On relative identity accounts of the Trinity, we do not heretically say, e.g., that the Father is absolutely identical with the Son, but instead we posit a same-essence (or same-God) relative identity relation, and say that the Father is same-essence as the Son. Now, most of the time proponents of relative identity views deny that there is any such thing as absolute identity at all. All identities are relative to a sortal. However, in their famous “Material Constitution and the Trinity”, Brower and Rea offer an account of the Trinity using relative identity within a system where there is such a thing as absolute identity, governed by the standard rules of first-order logic.

Any account of the Trinity that allows for absolute identity governed by classical logic faces an interesting problem. Suppose:

1. There is such a thing as absolute identity, denoted by “=” and governed by its standard first-order logic rules.

2. There is a name for God as such, “G”, and names for the Father, Son and Holy Spirit, respectively, “F”, “S” and “H”.

3. F ≠ S

4. S ≠ H

5. F ≠ H

6. For all x, if x = F or x = S or x = H while y = F or y = S or y = H, and if x = G, then y = G.

7. If x = x, y = y, z = z, w = w, x ≠ y, x ≠ z, y ≠ z, x ≠ w, y ≠ w and z ≠ w, then x, y, z and w are four, counting by absolute identity.

8. Then F, S, H and G are four, counting by absolute identity.

9. Heresy! In no sense is there a divine quaternity!

Premise (6) captures the idea that the persons of the Trinity have equality with respect to divinity, and hence if x and y are persons of the Trinity, then if either of x and y “is God” in some sense of “is” and “God”, then the other “is God” in the same sense.

Proof of 8 from 1–7:

1. If F = G or S = G or H = G, then F = G and S = G and H = G. By 6

2. If F = G and S = G, then F = S. By 1

3. So F ≠ G or S ≠ G. By 3 and ii

4. So F ≠ G and S ≠ G and H ≠ G. By i and iii

5. F = F, S = S, H = H. By 1

6. G = G. By 1

7. So, F, S, H and G are four, counting by absolute identity. By 3–5, iv–vi and 8

There is a way out of this, in van Inwagen’s work on the Trinity. Van Inwagen denies that there are names for the Father, Son, Spirit and God: there are just predicates, like “is divine” and “is a Father”.

This is overkill for getting out of the above. It is difficult for a Christian to completely deny the existence of divine names. After all, you become a Christian by having someone pour water over you while saying: “I baptize you in the name of the Father, and of the Son and of the Holy Spirit.”

I think the quaternity argument leaves Christians who want to uphold classical absolute identity with two options:

1. There is no name for God.

2. There are no names for the Father, Son or Holy Spirit.

Here, “name” means “proper name”, since that’s the kind of name that classical logic talks about.

Accepting both (a) and (b) is not, I think, an option. Of the two, I think (b) is the more problematic. Names are too central to human relationships with persons. Thus, I think, the Christian who wants to uphold classical absolute identity should accept (a). And there is some support in Christian tradition for denying that God has a name.

(This is not what Brower and Rea do. In footnote 7, they talk of “the name ‘God’”, albeit in the context of discussion of a heretical view, but as I read the footnote they have no reservation about “God” being a name.)

While (a) is the less problematic of the two options, I still think (a) is problematic. Grammatically, “God” and “the Trinity” and the tetragrammaton all function as proper names. While there is some precedent in the Christian tradition for denying that God has a name, that still seems a bit of a stretch.

I think that if one is going to adopt a relative-identity account of the Trinity, then one should either deny that there is such a thing as absolute identity or at least one should deny that it is governed by the rules of classical logic.

I tentatively propose the following modification to the classical theory of absolute identity as a way of getting out of the quaternity argument. Restrict the identity-introduction rule that says that for any name N we get to write down N = N to the case of what one might call hypostatic or individual names (or, perhaps, to non-essence names). Thus, we get to write “Father=Father” but not “God=God”. Now everything in the quaternity argument goes through, except we don’t get (vi) and and hence we can’t infer (vii) or (8).

The Sign of the Cross and the Trinity

A principle that both Catholic and Orthodox Christians appreciate is lex orandi, lex credendi: the law of prayer is the law of faith,

Now notice that we cross ourselves with the Trinity in a specific order: “In the name of the Father, and of the Son, and of the Holy Spirit.” This is probably the most common Christian prayer in the world. And it has an order: first, the Father is mentioned, then the Son, and then the Holy Spirit. The same order is found in the baptismal formula. While Eastern Christians tend to cross themselves right-to-left and Western Christians left-to-right, the order of the words is maintained (at least in the Churches where Trinitarian words are used: more details here).

It feels badly off to pray “In the name of the Father, and of the Holy Spirit, and of the Son.” Now, we might say that the feeling of its being “off” has a deflationary psychological explanation—we are just used to a specific order. Or, somewhat better, it is off insofar as it disconnects us from the practices of the community. But the universality of the order in the most common Christian prayer together with the theological methodology of lex orandi, lex credendi and the intuition that other orders aren’t as good should impel us to see theological significance in the order.

We might, of course, see a purely missional order here. First the Father is active in the world, then the Son, and then the Holy Spirit is sent. But I think we want more than just such a temporal ordering in our explanation. After all, while the Holy Spirit is especially sent in New Testament times, it seems right to talk of the Spirit’s activity in Old Testament times. And maybe even some of the explicit mentions of Ruakh Elohim, God’s Spirit, including at the beginning of Genesis, is already an indication of the economic involvement of the Spirit. It is at least better if we can ground what feels like an important feature of a central Christian prayer in something eternal.

One solution would be a subordinationist one: the Son is subordinate to the Father, and the Holy Spirit is subordinate to the Son. But that would be a heresy.

I propose that the filioque, whether formulated in terms of the Holy Spirit proceeding from the Father and the Son or from the Father through the Son, gives an elegant eternity-based account of what makes the order in the prayer appropriate. First, the Father, from whom the Son proceeds, and then the Holy Spirit who proceeds from the Father and/through the Son. The order is not that of subordination but of procession.

The filioque

Suppose we model the Trinity as three vertices with arrows between them representing relations of procession, such that:

1. No two vertices have two arrows between them and arrows only go between distinct vertices.

2. The arrows define the vertices in the sense that there is no way to relabel the vertices while preserving which vertex has an arrow to which vertext (i.e., there is no non-trivial directed graph automorphism).

There are seven different structures possible subject to (a).

Condition (b) is a way of capturing part of the traditional Western idea that the Trinity is relational, so that the distinctions between the persons arise from the processional structure. Four of the graphs violate this condition: in (1) we can rearrange the labels in any way without changing the relational structure; in (4) and (5) we can swap A and C; in (7), we can rotate the whole graph by 120 degrees.

Aquinas captures the relationality idea by the principle that person x is distinguished from person y if and only if there is a (real) processional relation between x and y. I think this principle is too strong in one way and too weak in another way. It is too strong, because (2) would allow the persons to be distinguished, even though there is no processional relation between A and C (or B and C): A would be the unique person from whom someone proceeds; B would be the unique person that proceeds; C would be the unique person unrelated by procession. It is too weak, because in (7) we have a processional relation between each person, but it fails to distinguish the three persons. Of course, (2) and (7) have other flaws.

The following options satisfy condition (b): (2), (3) and (6).

Graph (2) is theologically unacceptable, as it has a person not related to any other. And so while the relationality in (2) would be sufficient to define the persons, because C would be unrelated to A and B, the graph does not represent a fully relational Trinity. Besides which, (2) has two persons, A and C, who do not proceed from another, and the East and West agree that only the Father does not proceed.

Graph (3) is interesting. If we adopted this model of the Trinity, we would have to take A to be the Father, since everyone agrees that the Father does not proceed for anyone. Moreover, since everyone agrees that the Son proceeds from the Father, we would hae to

In graph (3), we would have to take A to be the Father, since the Father does not proceed from any other person, as the East and West agree. Likewise, the East and West agree that the Son comes from the Father. So B would have to be the Son. That would make the Holy Spirit be C, and proceed only from the Son. Neither the East nor the West will like this. And it would violate the principle that the Son eternally has nothing beyond what the Father has, excepting what follows from the Son’s being generated by the Father, since now the Son has the Spirit proceeding from him, but the Father does not. I suppose one might try to reconcile (3) with the Western view by saying that the Spirit proceeds mediately from the Father and immediately from the Son. I don’t like this.

That leaves graph (6), the Western view of the Trinity, with A being the Father, C being the Son and B being the Holy Spirit.

This isn’t really a great argument against the Eastern view of the Trinity, because the East will deny (b), on the grounds that one can distinguish the persons not merely by the directions of the procession, but by the types of processions, with generation and spiration being different types. One can think of this Eastern move as allowing the arrows to have different colors, and then instead of (b) having the condition that there is no way to relabel the vertices while preserving which vertex has an arrow of what color to what vertex.

The point here is rather to allow us to state with some precision what principles force the western view. Namely, we have:

Theorem: Suppose:

1. There are exactly three persons in the Trinity

2. The (binary) procession relation is asymmetric: if y proceeds from x, x does not proceed from y

3. At most most one person does not proceed from another

4. There is one person from whom both of the other persons proceed

5. There is no way to relabel the persons while preserving the procession relations.

Then there is a way of respectively naming the persons “Father”, “Son” and “Holy Spirit” such that it is correct to say: “The Father does not proceed, the Son proceeds from the Father, and the Holy Spirit proceeds from the Father and the Son.”

How has Aquinas not proved the Trinity?

St Thomas holds that we cannot know by natural reason that God is a Trinity. However, he also endorses a version of St Augustine’s account of the Trinity, on which God has a mental Word or concept of himself that he generates mentally, and then there is a Love that is responsive to that Word. Why is this not a proof by natural reason?

On this point, Thomas is sadly brief in the Summa Theologiae: “Again, the similarity with our intellect does not sufficiently prove anything about God, since the intellect is not found univocally in God and in us.”

But Aquinas thinks that we can literally talk about God, even if we do so by means of analogy. He has argued, by reason, that God exists and has all perfections. One of these perfections is knowledge of everything, and thus of himself. Does this not commit Aquinas to being able to say on the basis of natural reason that God generates his self-knowledge, a self-knowledge that, by divine simplicity, must then be God himself rather than a mere creature? And does not God love himself under the description that this knowledge provides?

I think Aquinas would (with perhaps minor cavils) endorse all the claims in my previous paragraph as knowable by natural reason. How is this not a proof of the Trinity? I think the answer is this. Focus on the generation of the Son—the case of the Holy Spirit will presumably be similar. We do not know by reason whether the relation of generating self-knowledge is a real relation in God. If it is a real relation it will individuate the knower from the knowledge, thereby ensuring that there are at least two persons in God. But it needs to be a real relation in God, rather than a merely conceptual one. And here Thomas’s brief remark about univocity seems apposite. Aquinas thinks that what makes our language about God analogical rather than univocal is that the grounding of claims about God is radically different from the grounding of similar claims about creatures. Thus, when we say Socrates is wise, this is grounded by the inherence in Socrates of an accident of wisdom, while when we say God is wise, this is grounded by the identity between God and his wisdom. Because of this, even if it turns out that in us the generation of self-knowledge is a real relation (but not one between persons, since we are not simple, and hence our self-knowledge does not need to be of one essence with us), since the grounding structure of claims about God is radically different, as far as unaided human reason goes, it may not be grounded in a real relation in God—though it might be. We need God’s revelation to know if it is a real relation or not. And indeed God has revealed that it is.

Mononoetism

Every so often I come against someone who is defending a Christological view I want to call “mononoetism”: that Christ has only one mind. While the Third Council of Constantinople condemned the errors that Christ has only one will (monothelitism) or only one natural operation (monoenergism), I do not know of any conciliar condemnation of mononoetism. Nonetheless, I think the reasoning behind the condemnations of monothelitism applies to mononoetism.

Mononoetism could in principle come in three sorts: Christ has only one mind and it’s a human mind; Christ has only one mind and it’s a divine mind; Christ has one hybrid human-divine mind. I think the first and second options are non-starters. If Christ has only a human mind, he’s not consubstantial with the Father. If Christ has only a divine mind, he has not taken on the human nature. So we should only consider the hybrid human-divine mind view.

But a hybrid human-divine mind view seems to be the kind of “confusion and mixture” between human and divine natures that the Council of Chalcedon objects to. Indeed, the letter of Pope Agatho, approved by the Council, shows that the opposition to monothelitism is just a working out of the teaching of earlier Councils, and Agatho’s reasoning applies just as much to the mind. Just replace “will” with “mind” here:

While if it is asserted that there is but one will in him (which is absurd), those who make this assertion must needs say that that will is either human or divine, or else composite from both, mixed and confused, or (according to the teaching of all heretics) that Christ has one will and one operation, proceeding from his one composite nature (as they hold). And thus, without any doubt, the difference of nature is destroyed, which the holy synods declared to be preserved in all respects even after the admirable union. Because, though they taught that Christ was one, his person and substance one, yet on account of the union of the natures which was made hypostatically, they likewise decreed that we should clearly acknowledge and teach the difference of those natures which were united in him, after the admirable union. Therefore if the proprieties of the natures in the same our one Lord Jesus Christ were preserved on account of the difference [of the natures], it is congruous that we should with full faith confess also the difference of his natural wills and operations, in order that we may be shown to have followed in all respects their doctrine, and may admit into the Church of Christ no heretical novelty.

Next, let’s think about the Trinity, and ask if there are three minds or one in the Trinity. On the mononoetism under consideration, Christ has to have the hybrid mind without also having a divine mind (or else he would have two minds: a hybrid one and a divine one). Then if all three Persons have one mind, it follows that the Father and Holy Spirit also have a hybrid human-divine mind, which is plainly absurd—it implies a partial Incarnation by the Father and by the Holy Spirit. So the mononoetist has to hold that each Person of the Trinity has a distinct mind. Mononoetism about Christ implies trinoetism about God.

Trinoetism about God seems to violate divine simplicity, but a trinoetist about God is likely to deny that, holding that mind does not go with the single divine substance or ousia but with the three Persons or hypostases. But let’s think this through. The argument from mononoetism about Christ to trinoetism about God is a special case of a general principle that what there is one of in Christ there is three of in God and vice versa. If the general principle holds, then we have to hold that there is one will in God. For if there were three wills in God, we would have one will in Christ, and that’s the condemned heresy of monothelitsm about Christ. Furhermore, the idea of three wills in God requires a story about why it is metaphysically impossible for these wills to disagree (for if they could disagree, then the three persons couldn’t each be omnipotent!). The best story would be a subordinationist one—the Son and Holy Spirit’s wills are obedient to the Father. But this seems contrary to the equality of the Trinity.

So let’s take it that God has but one will. Mononoetism about Christ has, however, led us to the idea that God has three minds. How does one will in three minds work? A will decides between options presented by a mind. But now things start to fall apart again. Even if the contents of the allegedly distinct minds of Father, Son and Holy Spirit are the same, there is still the question of which mind is the one that is informing the one divine will. If only one or two minds are informing the divine will, we lose the equality of Persons in the Trinity—one or two Persons are partly left out of decisions. So probably one has to say that the one divine will, uniquely, is equally and overdeterminately informed by three minds. This doesn’t seem right. For a person’s will looks to the person’s own mind. (Objection: If Alice loves Bob, she looks to Bob’s mind in her decisions. Response: Yes, but only indirectly by mirroring the contents of Bob’s mind in her mind.) And, besides this, it seems that divine simplicity requires that the divine will and the divine mind are the same thing, which completely rules out the idea of one will with three minds.

We can repeat the argument of the previous paragraph with operations or energeiai. Monoenergism about Christ is condemned. Christ has two operations. On general principles, then, we would expect one operation in the Trinity, just as one will. But if there are three minds, it seems there are three operations, since a mind operates (its operation grounds the thinking of the person or persons who with the mind).

Next, let’s think about the alleged hybrid human-divine mind of Christ. In forming this hybrid mind, the divine mind of Christ seems to have changed—it has hybridized. For if it has not changed, then we still have the divine mind in addition to the hybrid one. But divine minds cannot change, since God cannot change! Indeed, the divine mind is presumably timeless. If it is timeless, it eternally exists. Thus it seems that on mononoetism Christ does have two minds after all, and so we do not have mononoetism: he has the hybrid mind and the eternally existing divine mind. This is, however, a kind of difficult argument to run. Can one not make the exact same objection to the Incarnation? How can the divine Person not change in the Incarnation? Well, orthodoxy says that the divine Person remains a divine Person. But on the hybrid human-divine mononoetism, the divine mind does not remain a divine mind, or else Christ would have two minds.

Perhaps, though, the mononoetist can try for a “smaller” version of the Incarnation: just as the divine Person comes to take on humanity, so we have one Person with two personal natures, human and divine, the divine mind comes to take on human mentality, so we have one Mind with two mental natures, human and divine. Perhaps ths would allow one to avoid the rather monstrous sounding “hybridization” that I have been assuming earlier. But here is a problem. By divine simplicity, the only distinctions in God are relational distinctions between the Persons. If God has one mind, that mind is identical to God. As argued earlier, if there is one mind in Christ, there are three in God, one per Person. But by the only-relational-distinctions principle, the mind of each person must be identical to the Person. If then the divine mind of the Logos comes to take on human mentality, so that it is both a human mind and a divine mind, like the Logos taking on humanity so that the Logos is both human and divine, then since the divine mind is identical with the Person, the Logos, it follows that the Person also takes on human mentality. Thus, the Logos is now three things: God, human and a human mind. We can say that the Logos became man, but we can also the Logos became a man’s mind. This requires a kind of inhuman relationship between the man and the man’s human mind: Jesus is Jesus’s human mind (which on this version of mononoetism is also identical with Jesus’s divine mind). Of course, Cartesians who think you are your mind won’t think there is anything strange about that. But they are wrong! And it would be very odd if Cartesianism were true about Jesus but about no one else. That would seem to undercut the idea that Jesus is like us in all human things but sin.

It is thus quite difficult to hold to mononoetism about Christ while rejecting monothelitism and monoenergism. And in any case there is a neat inductive argument: two wills, two operations, so probably two minds.

The three big mysteries of the concrete world

There are three big mysterious aspects of the concrete world around us:

• the causal

• the mental

• the normative.

The three mysteries are interwoven. Teleology is the domain of the interplay of the causal and the normative. And the mental always comes along with the normative, and often with the causal.

There is no hope of reducing the normative or the mental to the causal. Some have tried to reduce the normative to the mental, either via relativism (reducing to the finite mental) or Plantingan proper functionalism (reducing to the divine mental), neither of which appears particularly appealing in the end. I’ve toyed with reducing the mental to the normative, but while there is some hope of making progress on intentionality in this way, I doubt that there is a solution to the problem of consciousness in this direction.

Theism provides an elegant non-reductive story on which the three mysterious aspects of concrete reality are all found interwoven in one perfect being, and indeed follow from the perfection of that perfect being.

I wonder, too, if there is some way of seeing the three mysteries as reflective of the persons of the Trinity. Maybe the Father, the ultimate source of the other persons, is reflected in causality. The Son, the Logos, in the mental. And the Spirit, the loving concord of the Father and the Son may be reflected in the normative. But such analogies can be drawn in many ways, and I wouldn’t be very confident of them.

Self-locating beliefs in the Trinity

Here is a difficulty for the doctrine of the Trinity that I don’t remember coming across before:

1. The Father and the Son have the numerically same divine mind.

2. If x and y have the numerically same divine mind, then x and y have the same divine beliefs.

3. The Father has an “I am the Father” divine belief.

4. So, the Son has an “I am the Father” divine belief. (1–3)

5. An “I am the Father” divine belief in the Son would be false.

6. There are no false divine beliefs.

7. So, the Son has no “I am the Father” divine belief. (5–6)

8. Contradiction!

Here, premise (1) follows from the heuristic that what there are two of in Christ, there is one of in the Trinity: there are two minds in Christ, so one mind in the Trinity. Non-heuristically, if there are two minds in Christ—the human and the divine mind—the mind must be a function of the nature, and as there is one divine nature in the Trinity, there is one mind in the Trinity.

There is a quick way out of the paradox: Restrict premise (2) to propositional beliefs rather than de se or self-locating beliefs. The belief that would be expressed in English by “I am the Father” is a de se or self-locating belief. There are corresponding propositional beliefs, such as the belief that the Father is the Father and the Son is the Son, but these are unproblematically had in common by the Father, the Son and the Holy Spirit.

However, while this quick way gets one out of the argument, it nonetheless leaves raises the difficult question of how it is the Father knows de se that he is the Father and the Son knows de se that he is not the Father, while yet there is one mind.

The solution had better be in terms of the relations between the divine persons, for there is no difference between the persons of the Trinity except the relational. I am reminded here of Thomas’s discussion of creation and the Trinity:

And therefore to create belongs to God according to His being, that is, His essence, which is common to the three Persons. Hence to create is not proper to any one Person, but is common to the whole Trinity.

Nevertheless the divine Persons, according to the nature of their procession, have a causality respecting the creation of things. For as was said above, when treating of the knowledge and will of God, God is the cause of things by His intellect and will, just as the craftsman is cause of the things made by his craft. Now the craftsman works through the word conceived in his mind, and through the love of his will regarding some object. Hence also God the Father made the creature through His Word, which is His Son; and through His Love, which is the Holy Ghost. And so the processions of the Persons are the type of the productions of creatures inasmuch as they include the essential attributes, knowledge and will.

Thus, each divine person is fully the Creator, but is fully the Creator in a way that takes into account the relationship that defines the person in the Trinity: the Father creates in a Fatherly way, the Son as the Logos through which creation is done, and the Spirit as the Love in which creation is inspired. What makes it be the case that the Father creates in a Fatherly way is just that the Father creates and he stands in the relations that constitute him as Father; what makes it be the case that the Son creates in a Filial way is just that the Son creates and he stands in the relations that constitute him as Son; and similarly for the Holy Spirit.

We might thus imagine the following story. There is a state F of the divine mind such that the Father’s Fatherly instantiation of F constitutes F into a belief that he (de se) is the Father. The Son instantiates the numerically same state F in a Filial way. But while a Fatherly instantiation of F is correctly described in English as constituting an “I am the Father” belief, a Filial instantiation of F is not aptly so described. Perhaps, a Filial instantiation of F is aptly described as a believing of “I am the Son of the one who is the Father.” Thus, the de se beliefs of the persons of the Trinity are constituted by mental states common to the Trinity and the relations constituting the persons.

The memory theory of personal identity and the Incarnation

Memory theories of personal identity don’t work for the Incarnation. For Christ’s human mind cannot remember what Christ’s divine mind thought, as it infinitely exceeds the capacity of a human mind.

Objection 1: The Catholic tradition holds that Christ always had the beatific vision. In the beatific vision, the simple God becomes the object of contemplation, and since the simple God is identical with his thoughts, God’s thoughts become the object of contemplation as well.

Response: That’s not memory. And if it were, then memory theories would imply that the blessed in heaven are one person with Christ.

Objection 2: It is not necessary that Christ as human remember Christ’s divine thoughts, but only that Christ as divine see Christ’s human thoughts.

Response: If Christ’s divinely seeing Christ’s thoughts makes for an identity of persons, then absurdly God is also identical with all of us, since God sees all our thoughts.

Objection 3: Memory theories concern identity across time. But Christ’s human and divine natures exist at the same time, if God is omnitemporally eternal, or Christ’s human nature exists in time and the divine nature exists outside of time. In neither case does we have identity across time, and so the memory theory of diachronic identity is unaffected.

Response: If God is omnitemporally eternal, we have another counterexample. Orthodox theology holds that there is one divine mind. Thus, the Son’s thoughts at t₁ the Father’s thoughts at t₁, and hence what the Father remembers at t₂ of what he had thought at t₁ is just as much a memory of what the Son had thought at t₁, which implies the heretical conclusion that the Father at t₂ is identical with the Son at t₁. So, the suggestion in the objection only has a hope if God is outside of time.

Next observe Christ is like us in all things but sin. In particular, he is as capable of amnesia as we are. Suppose Christ suffered amnesia at t₂, so that at at a later time t₃ he did not remember what he thought at an earlier time t₁. But the metaphysical bond between the divine nature and the human nature would surely not be broken by amnesia. So the human being named “Jesus” at t₃ would be the same person as the Second Person of the Trinity, and the human being named “Jesus” at t₁ would also be the same person as the Second Person of the Trinity. Thus, by symmetry and transitivity of identity, the human being named “Jesus” at t₃ would be the same person as the human being named “Jesus” at t₁, despite there being no memory connection, and hence contradicting the memory theory of personal identity.

Perhaps, though, it can be claimed that the Incarnation would of logical necessity be terminated by amnesia. But surely if the Incarnation were terminated, the Second Person of the Trinity could become incarnate once again. In this subsequent incarnation there need be no memories of the first incarnation. Yet if the first-incarnate Son were the same person as the Second Person of the Trinity, and the second-incarnate Son were the same person as the Second Person of the Trinity, it would follow that the first-incarnate Son would be the same person as the second-incarnate Son, once again leading to a case of diachronic identity that contradicts the memory theory of personal identity.

Three levels of theological models

There are three kinds of metaphysical models of a theological mystery—say, Trinity, Incarnation or Transubstantiation:

• realistic model: a metaphysical story that is meant to be a true account of what makes the mysterious doctrine be true

• potential model: a metaphysical story that is meant to be an epistemically possible account of what makes the mysterious doctrine be true

• analogical model: a story that is meant to be an epistemically possible account of what makes something analogous to the mysterious doctrine be true.

For instance, Aquinas’s accounts of the Trinity, Incarnation and Transubstantiation are realistic models: they are meant to be accounts of what indeed makes the doctrines true. Van Inwagen’s relative identity account of the Trinity or his body-snatching account of the resurrection, on the other hand, are only potential models: van Inwagen does not affirm they are true. And the history of the Church is filled with analogical models.

A crucial test of any of these models is this: Imagine that you believe the story to be true, and see if the traditional things that one says about the mystery (in the case of a realistic or potential model), or analogues of them (in the case of an analogical model), sound like reasonable things to say given what one believes.

For instance, consider a time-travel model of the Incarnation. Alice, currently a successful ultramarathoner and brilliant geologist, will live a long and fruitful life. Near the end of her life, she has lost most of her physical and mental powers, and all her knowledge of geology. She uses a time machine to go back to 2020 when she is in her prime. If we thought this story was true, it would be reasonable to find ourselves saying things like:

• Alice is a successful ultramarathoner and barely able to walk

• Alice understands continental drift and does not not know what magma is

• Alice is young and old

• Alice is in the pink of health and dying.

These things would sound like a contradiction, but the time-travel story shows they are not. However, these claims are also analogous to claims that constitute an especially mysterious part of the mystery of the Incarnation (and I suppose a mysterious part of a mystery is itself a mystery): Christ suffers and is impassible; Christ is omniscient and does not know everything; Christ is timeless and born around 4 BC.

Of course nobody should think that it’s literally true that the Incarnation is to be accounted for in terms of time travel. But what the analogical model does show is that there are contexts in which it is reasonable to describe a non-contradictory reality in terms that are very similar to the apparently contradictory incarnational claims.

Reality is strange

The doctrines of the Trinity, the Incarnation and transubstantiation initially seem contradictory. Elaborate theological/philosophical accounts of the doctrines are available (e.g., from St. Thomas Aquinas), and given these, there is no overt contradiction. But the doctrines still seem very strange and they feel like they border on contradiction, with the accounts that remove contradiction sometimes looking like they are ad hoc designed to remove the contradiction from the doctrine. This may seem like a good reason to reject the doctrines.

But to reject the doctrines for this reason alone would be mistaken. For similar points can be made about Relativity Theory and Quantum Mechanics. To say that simultaneity is relative or that a physical object has no position but rather a probability distribution over positions borders on contradiction, and the philosophical moves needed to defend these seem ad hoc designed to save the theories. If we’ve learned one thing from physics in the 20th century, it is that the true physics of the world is very strange indeed.

Nor are theology and science the only places where things are strange. Similar things can be said about the mathematics of infinity, or even just common sense claims such as that there is change (think of Zeno’s paradoxes) or that material objects persist over time (think of the Ship of Theseus and the paradoxes of material composition).

We can, thus, be very confident that created reality is very strange indeed. And hence, shouldn’t we expect similar strangeness—indeed, mystery—in the Creator and his relationship to us?

The Trinity, sexual ethics and liberal Christianity

Many Christians deny traditional Christian doctrines regarding sexual ethics while accepting traditional Christian Trinitarian doctrine. This seems to me to be a rationally suspect combination because:

1. The arguments against traditional Christian sexual ethics are weaker than the arguments against the doctrine of the Trinity.

2. A number of the controversial parts of traditional Christian sexual ethics are grounded
   at least as well in Tradition and Scripture as the doctrine of the Trinity is.

Let me offer some backing for claims 1 and 2.

The strongest arguments against traditional Christian sexual ethics are primarily critiques of the arguments for traditional Christian sexual ethics (such as the arguments from the natural law tradition). As such, these arguments do not establish the falsity of traditional Christian sexual ethics, but at best show that it has a weak philosophical foundation. On the other hand, the best arguments against the doctrine of the Trinity come very close to showing that the doctrine of the Trinity taken on its own terms is logically contradictory. The typical Christian theologian is the one who is on the defensive here, offering ways to resolve the apparent contradiction rather than giving rational arguments for the truth of the doctrine.

There are, admittedly, some arguments against traditional Christian sexual ethics on the basis of intuitions widely shared in our society. But we know that these intuitions are very much shaped by a changing culture, insofar as prior to the 20th century, one could run intuition-based arguments for opposite conclusions. Hence, we should not consider the arguments based on current social intuitions to be particularly strong.
But the intuition that there is something contradictory about the doctrine of the Trinity does not seem to be as dependent on changing social intuitions. The merely socially counterintuitive is rationally preferable to the apparently contradictory.

Neither the whole of the doctrine of the Trinity nor the whole of traditional Christian sexual ethics is explicit in Scripture. But particularly controversial portions of each are explicit in Scripture: the Prologue of John tells us that Christ is God, while both Mark and Luke tell us that remarriage after divorce is a form of adultery, and Paul is clear on the wrongfulness of same-sex sexual activity. And the early Christian tradition is at least as clear, and probably more so, sexual ethics as on the doctrine of the Trinity.

I am not saying, of course, that it is not rational accept the doctrine of the Trinity. I think the arguments against the doctrine have successful responses. All I am saying is that traditional Christian sexual ethics fares (even) better.

Yet another theory of ineffability

There is a long-standing tradition of trying to explain (!) the attribute of divine ineffability. Theories that are metaphysical in flavor rule the roost:

1. The only true assertions we can make about God are negative. (Eastern tradition)

2. The only true assertions we can make about God are analogical. (Aquinas)

3. The only true assertions we can make about God are non-fundamental. (Jacobs)

I want to add one more theory to the mix, one that can either be stand-alone or a complement to (1)–(3). This one is more epistemological:

4. The only assertions we can make about God are misleading.

One can illustrate the misleadingness of true, and even literally true, statements by examples.

• “Alice did not treat minorities as badly as Hitler” (when Alice was in fact an exemplary promoter of social justice).

• “Bob is somewhere in this building” (when he is standing right behind you).

• “I saw Carl in a car on I-35 this morning” (but the car was being towed by a truck).

• “Davita passed some of her exams” (when she passed all of them).

• “On a good day, Roger Bannister could run an 8 minute mile.”

Note that while (1)–(3) are limited to true statements, (4) does not have this restriction. After all, all false statements are misleading.

For concrete theological examples, think of how the doctrine of the Trinity shows that the doctrine of the unity of God is misleading, or the doctrine of the Incarnation shows that the doctrine of the transcendence of God is misleading. In a similar same way, when the doctrines of the Trinity and Incarnation are taught apart from the doctrines of unity and transcendence, they are misleading. But by (4) something more pessimistic is true: even when we teach Trinity and unity (or Incarnation and transcendence) together, we still mislead. I suspect that in heaven we will learn something that changes our understanding of unity and Trinity at least as much as the doctrine of the Trinity changed our understanding of unity.

Alvin Plantinga gives this counterexample to the thesis that we cannot say anything literally true of God: “God is not a bicycle.” If (4) is true, even this statement is misleading. In what way? Well, maybe it leads us to forget the intimate link between all reality and God: that all the reality in a bicycle is a participation in God.

Note that if (4) is true, then it is misleading. But that’s not a refutation.

One could also restrict (4) if one wanted to. For instance, one could restrict (4) to non-negative statements, or to non-analogical ones, or to non-fundamental ones.

I don’t know if (4) is true.

The mystery of God

Suppose you have never heard music, and you are watching a video of a superb ballet, with the sound turned off. And then someone turns the sound on. You now know a dimension of the dance you wouldn’t have expected or thought of. It transforms your understanding of the ballet radically.

Similarly, but more radically, when we humans learned that the perfectly one God is three persons, we learned something that we would not have expected, something that not only we wouldn’t have thought of, but something that we would have likely denied is at all possible. It is something that should radically (in both the etymological and the common senses of the word) transform all of our understanding of God. Of course, what we learned turns out to be logically compatible with the doctrine of God’s unity, but that it was compatible is a part of the surprise.

I suspect that similar transformations of our understanding of God await in heaven. Doctrines that are related to our doctrinal understanding of God as the doctrine of the Trinity is to the unity and simplicity of God. Experience that are radically different in kind from anything we have had.

But is it not plausible that God is such that any finite understanding of him is subject to such transformation? If so, then this gives us one way of countering the “eternal ennui” worry about heaven. For such transformations of our understanding of, and hence of our loving relationship with, God could occur for eternity then.

A Trinitarian structure in love

On my view, love has a three-fold structure:

• benevolence
• appreciation
• union.

This three-fold structure has certain Trinitarian parallels. The Father is the benefactor: he gives being to the Son and thereby to the Holy Spirit. The Son admires the Father, is the Logos that reflects upon the Father’s goodness. The Holy Spirit unites the Father and the Son.

Life

Accounts of biological life characterize it by lists of features such as “reproduction, metabolism, functional organization, growth, responsiveness to the environment, movement, and short- and long-term adaptations” (SEP s.v. life). But Jewish, Christian and Muslim theists have reason to worry about such accounts of life in the light of the fact that our scriptures present God as the paradigm of a living being.

Here are some options:

Option 1: Modify one’s theology to make God fit with something pretty close to one of the biological accounts of life. Mormonism is a fairly radical example of this. A more moderate version might be some version of process theology, though one may need to jettison some features, like metabolism and growth.

Option 2: Trinitarians have this option available: The Son proceeds from the Father and the Spirit from the Father and/through the Son and these processions could count as reproduction. Moreover, because Trinitarian processions multiply persons but the resulting persons are one God, Trinitarian reproduction has an internality that might count as a kind of growth—not that the divine essence grows, but that the number of persons of the one God grows. This solution would have the important consequence that the Old Testament texts that present God as living are proto-Trinitarian. Obviously, this solution is unlikely to be attractive to Jews and Muslims, though there may be some Kabbalistic analogue that might appeal to some Jews. Moreover, unless one adopts some version of process theology, this solution still requires one to drop a number of the features in traditional accounts of biological life, such as metabolism, movement and adaptation.

Option 3: Replace the biological accounts of life with something radically different which makes God a paradigm instance of life. Here are three such possibilities for characterizing life:

A. Living things are ones that have some mental property like consciousness or purposefulness.

B. Living things have teleology.

C. Living things are ones that have a well-being, that are capable of being well.

Suboption A is pretty radical: it requires either saying that plants have a mental life or that plants aren’t alive. I think it’s not that crazy to say that plants have something like mental life. Maybe they are aware of their environment in a way that goes robustly beyond the mere data processing of a digital thermometer. And it seems plausible that one can ascribe a certain kind of purposefulness to plant processes.

Suboption B is pretty close to the purposefulness variant of suboption A, but teleology is a more general concept than mental purposefulness. For me, the main difficulty with suboption B is that I think all substances have teleology. And I don’t want to extend life to elementary particles. But those who do not think that teleology extends to all substances might like Suboption B.

Suboption C is, of course, related to Suboption B. I have the same worry about C as about B: I think all substances that have teleology have a well-being. Elementary particles have well-being—the only difference between them and organic substances is that as far as we can tell, elementary particles are always well. This is of course very controversial, and those who do not accept it may like C.

There are, no doubt, other options and suboptions. I am attracted to Options 2 and 3A.

A Trinitarian structure in love

In One Body, I identified three crucial aspects in every form of love: benevolence, appreciation and unity. But I did not have an argument that there are no further equally central aspects. I still don’t.

But I now have some suggestive evidence: There is a Trinitarian structure to these three aspects. The Father eternally conferring his divine nature—the nature of being the Good Itself—on the Son and, through the Son, on the Holy Spirit. The Son in turn eternally and gratefully contemplates the Father. And the Holy Spirit joins Father with Son. This makes for benevolence, appreciation and unity, respectively, all perichoretically interconnected. That there are only three Persons in the most blessed Trinity is thus evidence that these three aspects are what love is at base.