The Argument from Coexistent Communities

Hebblethwaite's most recent reiteration of his main argument for the impossibility of multiple incarnations of the same divine person is as follows:

He goes on to quote his own earlier phrasing that I quoted above:

Call this argument the Argument from Coexistent Communities.

The argument has received some attention in the literature, though just what, exactly, the form of the argument is has been disputed. Kevern (Reference Kevern2002, 343), Crisp (Reference Crisp2009, 157–164), and Le Poidevin (Reference Le Poidevin, Marmodoro and Hill2011) all analyse arguments from Hebblethwaite, but in different ways. In what follows, I will present their interpretations before presenting my own. Crisp and Le Poidevin interpret the argument above, whereas Kevern interprets an argument I go on to discuss later. As such, I turn my attention to Crisp and Le Poidevin here.

Crisp claims that Hebblethwaite requires three additional but unstated premises to reach his conclusion. Crisp (Reference Crisp2009, 158–159) says they are (keeping his numbering):

1. 1. Any human nature assumed by a divine person is numerically identical with that divine person.

2. 2. A divine incarnation has to be the same person, human as well as divine.

3. 3. A divine person can have at most one human nature.

By ‘human nature’, Crisp means a concrete nature. That is, a flesh and blood entity. What St Cyril, in the documents from the Council of Ephesus, refers to as ‘flesh enlivened by a rational soul’, or what the anathemas from the 5th Ecumenical Council, Second Constantinople, refer to as ‘human flesh which is possessed by a rational and intellectual soul’ (Tanner (Reference Tanner1990), I, 41, 115). Such an understanding of nature is the common interpretation of the schoolmen.Footnote ⁴ This is the understanding of ‘human nature’ which I will be using throughout this article. In this sense of the term, the nature is an individual thing, but need not be an ultimate subject of a life, to use Hebblethwaite's terminology. In cases of incarnation, the person doing the assuming is the ultimate subject of life.

I do not agree with Crisp's claim that these three assumptions are required. It appears to me that Crisp's 3 is the conclusion that Hebblethwaite is striving for. For if 3 is true, then it follows trivially, from 3 alone, that it is impossible for Christ, the divine person, to have more than one human nature. But the possibility of multiple incarnations under dispute here requires precisely that it is possible that Christ have more than one human nature. Going in the other direction, if Hebblethwaite's conclusion is true and multiple incarnations are impossible, it follows straightforwardly that no divine person can have two human natures, since that would be a case of multiple incarnations. So I doubt that Hebblethwaite would be happy having to take on 3 as an assumption, since assuming 3 for the sake of proving the impossibility of multiple incarnations begs the question.

Consider the first assumption. I have grave reservations here, too. Crisp says that ‘the first assumption is commonplace in Christology: many theologians maintain that Jesus of Nazareth just is God incarnate’ (Crisp (Reference Crisp2009), 159). I agree that it is commonplace for theologians to think that Jesus is God incarnate. However, I deny that this is relevant to 1, since 1 is not making an identity claim between the relata: Jesus of Nazareth and God incarnate. It is making an identity claim between the relata: Christ's assumed human nature (call it ‘CHN’) and the divine person. CHN is neither Jesus of Nazareth nor God incarnate. The name ‘Jesus’ names a person, but the assumed human nature itself is no person. While Crisp concedes the truth of the first assumption in his analysis, I will go on to reject it. But I should say that I see the impetus to claim that Hebblethwaite is relying on assumption 1, as will become clear in my forthcoming analysis of the argument.

Le Poidevin, too, claims something similar to Crisp's first assumption. The first premise of Le Poidevin's careful analysis of Hebblethwaite's argument is, following his numbering (Le Poidevin (Reference Le Poidevin, Marmodoro and Hill2011), 231):

1. (1) If the Son is incarnate in x, then the Son = x.

Le Poidevin claims that this premise is a part of traditional Christology. He writes (ibid., 231): ‘(1) is implied by the traditional doctrine of the incarnation: incarnation is identity.’Footnote ⁵ Whether or not Le Poidevin is correct here relies upon what he takes the relation of ‘incarnate in’ to be in Premise 1. To my mind, this seems true: ‘the Son was incarnate in CHN’. More generally, a divine person is incarnate in whatever nature that divine person assumes. But if that is what Le Poidevin means by ‘incarnate in’ in Premise 1, then the premise is the same as Crisp's first assumption. As I said previously, I will go on to reject this identity claim.

Perhaps, instead, Le Poidevin means by ‘incarnate in’ something else. Perhaps we can bring out the meaning clearly if we add a suffix to the relation – ‘incarnate in the person’. If the Son is incarnate in the person, x, then the Son is identical with x. That seems true to me, though it sounds as if there is a person that is not the Son, and the Son is incarnate in that person, which is contrary to the Christology of the first seven ecumenical councils (call that Christology ‘Conciliar Christology’). But on this reading, we get bizarre sentences such as ‘the Son is incarnate in the Son’ coming out true. Elsewhere, Le Poidevin writes (2011, 231) that ‘Incarnations are persons.’

Rather than rely upon the analysis of Crisp or Le Poidevin, in what follows I will provide my own.

The argument seems to me to go as follows. We start by assuming that it is possible for there to be multiple incarnations of the same divine person. Our goal is to derive a contradiction, and so show that our assumption is false. Conciliar Christology teaches that the predicates that an assumed, created nature would make apt of a mundane person, were that nature not assumed, the created nature makes apt of the divine person when assumed (i.e. the idioms are communicated). So the predicates apt of the assumed, created natures ‘spread to’ the Son, in a case of multiple incarnations. But now consider the eschaton. There, the ‘personal vehicles of the divine life’, that is, the assumed, created natures, coexist and are capable of interpersonal relation. And this, in turn, entails that one individual subject has become a coexistent community of persons. But it is impossible for one individual subject to become a coexistent community of persons. I take this impossibility claim to be quite important to the argument. Hebblethwaite saw fit to quote it in his later presentation of his argument, which leads me to think that he took this passage to present his intent well. Thus, since a contradiction was derived from the initial assumption of the possibility of multiple incarnations, that purported possibility is no possibility at all – if the possibility of x entails the truth of a contradiction, and it is impossible for a contradiction to be true, then it is impossible for x to be true. And so it is not possible for there to be multiple incarnations of the same divine person.

One might formalize the argument as follows, letting ‘HN1’ and ‘HN2’ name human natures that are assumed in the allegedly possible situation in which the Son assumes two natures:

1. 1. Suppose that there are multiple incarnations of the same person in two natures, HN1 and HN2. (For reductio.)

2. 2. If the ultimate subject of Jesus's life is God the Son, then the ultimate subject of any incarnation [of the Son] is God the Son.

3. 3. The ultimate subject of Jesus' life is God the Son.

4. 4. The ultimate subject of any incarnation [of the Son] is God the Son. (From 2, 3.)

5. 5. The ultimate subject of both HN1 and HN2 is God the Son. (From 4.)

6. 6. If the ultimate subject of both HN1 and HN2 is God the Son, then, in the eschaton, HN1 and HN2 coexist and are capable of interpersonal relation. (From Resurrection belief.)

7. 7. If, in the eschaton, HN1 and HN2 coexist and are capable of interpersonal relation, then one individual subject – God the Son – is capable of becoming a series of individuals, or a coexistent community of persons.

8. 8. One individual subject – God the Son – is capable of becoming a series of individuals, or a coexistent community of persons. (From 5, 6, 7.)

9. 9. It is impossible that one individual subject – God the Son – is capable of becoming a series of individuals, or a coexistent community of persons. (assume.)

10. 10. Contradiction! (8, 9).

11. 11. Thus, it is not the case that it is possible that there are multiple incarnations of the same person. (reductio, 1–10.)

What ought we to make of this argument? It is formally valid, as presented. So if the proponent of multiple incarnations of the same divine person is to reject it, she must reject at least one of the premises. But which?

The first premise, Premise 1, is an assumption made for reductio. Hebblethwaite is saying, suppose that this is true. An appropriate response at this juncture is not to say, ‘No, I will not suppose along with you.’ So rejecting 1 is not the way to go.

Consider, then, Premise 2. Here I insert ‘of the Son’ into Hebblethwaite's language since I take this to be his intent. I concede the truth of this premise. Conciliar Christology has it that in virtue of being assumed, the predicates that the created human nature would normally make apt of the merely human person in a non-assumption case are made apt of the divine person. According to St. Leo's Tome to Flavian (Tanner (Reference Tanner1990), I, 81), endorsed at the Council of Chalcedon, it is because the Son's human nature hung on a cross that it is true to say that the Son, or even that God, hung on the cross.Footnote ⁶ Since any other incarnation would be an instance of assumption, the same reasoning should apply in those cases as well. The predicates transfer to the Person.

The next premise, Premise 3, is unstated. Our taking seriously the point of the antecedent, as Hebblewaithe suggests we do, is, I take it, our granting it as true. And I do think that the proponent of Conciliar Christology is bound to assert the truth of that premise. So I will leave Premise 3 unchallenged as well. Premise 4 follows straightforwardly by Modus Ponens, and so it, too, deserves a pass. Premise 5 applies the generalization in Premise 4 to an allegedly possible case of multiple incarnations. It, too, is conceded.

The next moves are where the difficulties begin. Hebblethwaite claims that the foregoing steps of the argument, along with a belief in the resurrection, entail:

I take these ‘vehicles of divine life’ to be the assumed natures. And I concede that multiple incarnations would imply, given the doctrinal statements about the resurrection in the first seven Ecumenical Councils and elsewhere in the tradition (e.g. the Apostolic and Athanasian Creeds), that both HN1 and HN2 would exist in the eschaton. Would they be capable of ‘interpersonal relation?’ That depends upon the meaning of the term.

Consider some potential definitions.

What is it to make use of or involve something else's personhood? I have no definition to offer. But perhaps examples will be of use. If I use you as a chair, I am relating to you, but not relating to you qua person: I could use your corpse in the same way. And if I use you merely to warm my side of the bed, then, again, I am not relating to you qua person: I could use your dog in the same way. But if you and I converse about metaphysics, then you and I are related qua person, since it is in virtue of our rational natures that we are capable of having such a conversation.

Are HN1 and HN2 related to one another by Interpersonal Relation₁? No, I think. For neither HN1 nor HN2 fulfils any of the conjuncts of the right-hand side of Interpersonal Relation₁. Neither HN1 nor HN2 is a person, in the traditional sense of the term. For to be a person is to be a hypostasis with a rational nature, where ‘hypostasis’ means, as Alfred Freddoso (Reference Freddoso1986, 28) paraphrases the traditional notion, ‘an independently existing ultimate subject of characteristics’. Even if one eschews the traditional interpretation of personhood in these debates, the orthodox Christian, including Hebblethwaite, will be unwilling to allow for an assumed nature to be a person in any sense of the term, since that would entail two persons in the incarnation, which no orthodox thinker will admit. So HN1 and HN2 do not fulfil the conditions for being persons, and so do not fulfil the first condition of Interpersonal Relation₁. Rather HN1 and HN2 are assumed by a Person – the Son of God; it is false to say that each is a person. And since they are not persons, they cannot relate in ways that involve their personhood, any more than saints Aquinas and Bonaventure could relate in the eschaton in ways that involve their parenthood.

Perhaps, then, we should interpret interpersonal relations in the following way:

This definition of the term understands interpersonal relations to be relations between individuals that have rationality. HN1 and HN2 are rational; each is, as the texts of Conciliar Christology say of CHN, ‘flesh enlivened by a rational soul’, a ‘holy body rationally ensouled’, and ‘human flesh which is possessed by a rational and intellectual soul’ (Tanner (Reference Tanner1990), I, 41, 44, 115). I see no reason to think that HN1 and HN2 could interact rationally with mundane humans in the eschaton – say, by talking with them, or, perhaps better to say, by the Person of the Word talking through them – but that it is impossible for them to interact rationally with one another. And so, for my part, if it uses the second definition of interpersonal relations, I grant Premise 6.

Before I discuss Premise 7, which I think is false, I will briefly say a bit about each of the other remaining moves. Premise 8 follows from 5, 6, and 7. If ‘A’ is true, and ‘if A then B’ is true, and ‘if B then C’ is true, then, it follows that ‘C’ is true. That is precisely the inferential form in deriving 8 from 5, 6, and 7. And so, were 5, 6, and 7 true, 8 would be true as well.

Consider 9; I concede it.Footnote ⁷ It is impossible for one thing, x, to become two different (i.e. non-identical) things y and z. This is not to say that it is impossible for, say, a human to be sawn in half, as the unfortunate Apostle Simon the Zealot evinced as he earned his frond of palm. There, in a sense, one thing – a human – has become two things. Rather, it is impossible for a human to be sawn in half, and for each half to be identical to the original human, since each half has different properties, and no thing has properties different from itself. A thing and itself cannot go their (its?) separate ways.

Were one thing able to become identical with two different things, the transitivity of identity would have to be false:

For letting y name the original thing, and x and z name the different things, both conjuncts of the antecedent are true but the consequent is false. Y, the original thing, is identical with both x and z. But, since they are different, x and z are not identical. Thus, any who grant the truth of the transitivity of identity will grant the truth of 9. So I agree with Hebblethwaite that the situation he has claimed follows from multiple incarnations is, in fact, impossible. But I deny, as will become clear, that the situation does, in fact, follow from multiple incarnations of the same divine person.

Premise 10 follows from the two previous premises by conjunction. And the conclusion, 11, follows from the preceding steps. And so, given the truth of Premise 7, Hebblethwaite has proven his conclusion. But I deny that Premise 7 is true.

Recall that Premise 7 says:

1. 7. If, in the eschaton, HN1 and HN2 coexist and are capable of interpersonal relation, then one individual subject – God the Son – is capable of becoming a series of individuals, or a coexistent community of persons.

The truth of the antecedent follows from two premises I have already granted: 5 and 6, so I am rationally bound to accept that antecedent. I deny, however, that the antecedent implies the consequent.

Suppose the antecedent is true, and that HN1 and HN2 are interpersonally related, in the second sense of that term. Say, they are having a conversation, or, as it might be better to say, that the one Person, the Son, is talking to himself through them. How does that entail that the Son is a coexistent community of persons? Neither HN1 nor HN2, itself, is a person. No Conciliar Christologist should grant the claim that if there are two natures, then there are two persons. For the incarnate deity has two natures, and yet is one person. Furthermore, neither of the two natures fulfils the conditions for being a person, since a necessary condition for being a person is being unassumed, and, by hypothesis, both HN1 and HN2 are assumed. And so it is wrong to count them as persons. But then, if they are not the persons which make up the coexistent community of persons, who are the persons? There are no candidates for being the persons in the coexistent community of persons besides HN1 and HN2. I see no reason to think that the antecedent implies the Son's becoming multiple persons, and so no reason to think he becomes a coexistent community of persons.

Did God the Son become a series of individuals? Not as far as I can see. It is true that he assumed a series of individuals, HN1 and HN2. But it is false that he became identical with either of those two natures. (Here, I believe, we see why Crisp thought that Hebblethwaite needs the first assumption.)

I see no good reason to believe 7. And I see good reason to deny it. I see much support for the claim that it is not the case that the Son becomes identical to any nature that he assumes, or to the sum or set of assumed natures. Were an assumed nature – say CHN, the nature that the Son did, in fact, assume – identical to the Son, then, contrary to the teachings of Conciliar Christology: (i) CHN is itself a person (since the Son is himself a person); (ii) assumption is a relation that holds between a thing and its very self (since CHN is identical to the Son); (iii) the Son is a composite of body and soul (since CHN is such a composite); (iv) and there was a time before which the Son was not (since there was a time before which CHN was not). All four of these claims are precluded by Conciliar Christology. The identity claim that Hebblethwaite needs to show the incoherence of multiple incarnations is one that is both under-defended and falsified by Conciliar Christology.Footnote ⁸ On Conciliar Christology, no assumed nature becomes identical to the Second Person of the Trinity.

To conclude my discussion of this argument, I disagree with Hebblethwaite that multiple incarnations of the same divine person entails that one person becomes a coexistent community of persons.

The Argument from Divine Subjecthood

A second, related argument Hebblethwaite presents, which Kevern analyses, goes as follows:

In his analysis, Kevern writes of this passage:

For my own part, I neither see the logical form of the argument as Kevern presents it, nor the reason for claiming that these three indented lines present it. Hebblethwaite is not arguing that, as Kevern indicates with the ‘therefore’ in the third line of the equation, God the Son has only one, unique personality. Rather, he is arguing what appears to be provided as a second premise – that the Son cannot become incarnate twice. So it looks to me that Kevern has misdiagnosed the conclusion as being a premise, and the premise – if it is a premise of the argument – as being the conclusion.

Moreover, what logical inference rule would allow the concluding of the third line from the second and first? By Kevern's formalization, it would appear to be an identity rule (‘1 = 1 = 1’). But that's not the inferential pattern that Hebblethwaite is employing. The passage includes a conditional premise (‘If God the Son … one divine life’) that is not an identity claim. The passage includes no identity claims. It isn't that I see the logic but fail to see its inescapability; I don't see the logic as being what Kevern claims it to be.

I take Hebblethwaite's argument in this passage to be as follows:

1. 12. If God the Son is one divine subject, then only one human subject can actually be the incarnate, human, form of that one divine life.

2. 13. God the Son is one divine subject.

3. 14. Only one human subject can actually be the incarnate, human, form of that one divine life. (From 12, 13.)

The final sentence of the quotation from Hebblethwaite is given as proof for the conditional premise, Premise 12. Let the antecedent of 12 be named ‘D’ (for ‘divine subject’) and the consequent ‘H’ (for ‘human form’). If Hebblethwaite can show that it is false that D and not-H, then he has shown that it is true that if D, then H. This is true because ~(D & ~H) is logically equivalent with D → H. And I take the ‘otherwise’ sentence above to be saying something like this:

1. 15. If God the Son is one divine subject, but it is not the case that only one human subject can actually be the incarnate, human, form of that one divine life [that is, if (D & ~H)], then the Son would have a split personality.

2. 16. But the Son could not have a split personality.

3. 17. Thus, it is false that (God the Son is one divine subject, but it is not the case that only one human subject can actually be the incarnate, human, form of that one divine life) [that is, ~(D & ~H), from 15 and 16, Modus Tollens).

Since 17 is logically equivalent to 12, a proof of 17 provides support for 12 as well. What should we make of Hebblethwaite's main argument, and this justification of its first premise?

Since I deny the conclusion of his argument, and the argument is formally valid, I must deny a premise of the argument. I concede the truth of the second premise, Premise 13, so I must deny the conditional premise. And since the conditional premise is the conclusion of the second argument (15–17), which also is formally valid, I must deny a premise of that argument as well. Which premise I deny depends on the definition of ‘split personality’. Consider two cases.

If, on the one hand, having a split personality entails there being multiple persons, then I concede that the Son cannot have split personalities, as Premise 16 states. But then I also deny that taking on two human natures entails that there are multiple persons, for reasons given previously in discussion of Premise 7. And so, on this interpretation of having split personalities, I deny that 15 is true, since I grant its conjunctive antecedent but deny its consequent.

If, on the other hand, a split personality does not entail multiple persons, but instead entails multiple rational centres, or intellects, or something like that, then I concede the truth of 15 – becoming incarnate in more than one rational nature would entail the Son's having multiple rational centres. But then I also think that becoming incarnate in a single rational nature would entail the Son's having multiple rational centres! The Third Council of Constantinople (Tanner (Reference Tanner1990), I, 129–130) clearly teaches that the incarnate Son has two wills, which are the operations of the two distinct natures he has. And so I deny the truth of 16 – not only could the Son have split personalities, in this sense of the term, he in fact did have split personalities in this attenuated sense, according to Conciliar Christology.

Thus, whichever of these two understandings of ‘split personalities’ is true, I deny some premise or other of his Argument from Divine Subjecthood or the intermediate argument in support of Premise 12.

Now, there is a trivial sense in which 14, ‘only one human subject can actually be the incarnate, human, form of that one divine life’, is true. Given the definite article in the premise, there couldn't be more than one human subject that is the incarnate, human form of the one divine life, any more than we can say of a woman or her sister that she is the daughter of their mother. But since the very question at stake here is whether there could be more than one incarnate, human form of the one divine life, we ought not to let the ‘the’ settle the question. For if we read the ‘the’ in such a robust sense, so as to require it to preclude multiple incarnations, then no proponent of multiple incarnations will grant 12, since it includes the ‘the’ claim that automatically precludes multiple incarnations.

Similarly, later on the same page Hebblethwaite says (2001, 324),

Here again there is a suspicious definite article – ‘the risen Christ is the human face of God for ever’. But even aside from that point, there is reason to be sceptical of this inference. I concede that the suspicious definite article is apt in the sentence. We may take ourselves to have good reason to think that there will be but one incarnation in the actual creation.Footnote ⁹ But I deny that it shows us anything about whether, in a different creation, there could be multiple incarnations. That is, even if it is true, and we have good reason to believe, that the human nature Christ assumed is the human face of God forever, that is insufficient to show that there cannot be a number of such faces in another situation, under another providential plan.