The God-Man Identity Theory
Central to Christianity is the doctrine of the Incarnation: God became man in Jesus of Nazareth. To be precise, the claim is that God the Son (the Logos, the Word) became man in Jesus of Nazareth. Thus the doctrine of the Incarnation presupposes the doctrine of the Trinity, according to which the one God is composed of three divine persons, Father, Son, and Holy Ghost. The other two Abrahamic religions, Judaism and Islam, reject both of these doctrines, and on my understanding of their positions, they reject them for roughly the same reason, namely, that Incarnation and Trinity violate the radical transcendence and the radical unity of God. Christianity tries to combine transcendence and immanence: God the Father remains radically transcendent, while God the Son enters into history.
Both of the Christian doctrines pose serious logical problems which threaten their coherence. Joseph Jedwab and I have been discussing the orthodox Chalcedonian construal of the Incarnation and my objections to its coherence. To read my published paper on this topic, go here. To read my responses to Jedwab’s first set of comments on the paper, go here. In this post, I examine a response to one of my arguments from Jedwab’s second set of comments.
Finally, you present what you describe as a very simple and compelling argument:
(12) If a = b, then necessarily a = b.
(13) If possibly ~(a = b), then ~(a = b).
(14) Possibly ~(the Son = Jesus).
(15) ~(The Son=Jesus).
BV: Let me explain this for the sake of the uninitiated. (Part of the mission of this weblog is to dispense free philosophy lessons.) The ‘=’ sign stands for numerical, as opposed to qualitative, identity. What (12) says is that if two individuals are identical (one and the same), then this is necessarily the case. Thus if two things are identical (the morning star and the evening star, for example), this is not mere contingently the case. If two putatively distinct things are really one thing, then they cannot both exist and yet be numerically distinct.
(13) follows from (12) by Contraposition. The tilde (‘~’)represents propositional negation. (13) says that if it is (broadly logically) possible that two individuals be distinct, then they ARE distinct. One (logically) cannot accept (12) without accepting (13).
(14) says that it is possible that God the Son, the second person of the Trinity is distinct from the man, Jesus of Nazareth. In terms of possible worlds: there is a possible world W in which the Son exists, but is not identical to Jesus, either because Jesus does not exist in W, or because the Son is not incarnated in Jesus in W. (14) expresses the fact that the Incarnation might not have occurred: God might not have become man. Presumably, the Incarnation would not have occurred had it not been for Adam’s ‘happy sin’ (felix culpa). No Fall, no need for Incarnation. Note also that God’s sending his Son into the world was a free act, which it could not be were the Incarnation a necessary occurrence.
(15) follows from (13) and (14) by Modus Ponens and Universal Instantiation. What (15) says is that God the Son is not identical to Jesus.
Now, given that orthodox Chalcedonian incarnationalism makes a claim of strict numerical identity, then OCI is false.
Jedwab: Actually I would qualify (12). I think this holds where a and b are necessary beings, but I think, where a and b are contingent beings, a = b is false in worlds where a and b do not exist. So I think we should call this the essentiality of identity rather than the necessity of identity. But this in no way affects the point of the argument.
BV: Excellent point. Still, if a and b are contingent beings, and a = b, then in every possible world in which both exist, a = b. This is all I need for my argument, as you well appreciate.
Of course, I reject (14) and offer the following argument:
(13) If possibly ~(a = b), then ~(a = b).
(~15) The Son = Jesus.
(~14) Necessarily the Son = Jesus.
You support (14) by saying that the Son is contingently human and so possibly distinct from everything human and so possibly distinct from Jesus. But this assumes that Jesus is essentially human, which I also reject. Necessarily the Son is Jesus, but the Son is contingently incarnate and so Jesus is contingently incarnate.
BV: Why must I assume that Jesus is essentially human? The Son is a necessary being, but it is a contingent fact that he is incarnated: after all, the Incarnation is a free and supererogatory act of divine agape. So, the Son is possibly distinct from everything human, and so possibly distinct from Jesus. It doesn’t matter whether Jesus is essentially or accidentally human. Furthermore, it contradicts orthodoxy to say that “Necessarily, the Son is Jesus.” For that implies that the Incarnation occurs in every possible world. Finally, I would say it makes no sense to say that “Jesus is contingently incarnate.” For it is not Jesus that is incarnated, but the Son. Jesus is not the agent of Incarnation, but its ‘receptacle’ so to speak, or ‘locus’ as I say in my paper. You are ignoring something I take to be self-evident, namely, the asymmetry of Incarnation: if x is incarnated in y, then it is not the case that y is incarnated in x.
Perhaps here is the heart of the problem: identity is a symmetrical relation; incarnation is asymmetrical.
I shall try to diagnose our disagreement concerning the possibility of the Incarnation. I am thinking of humanity as involving a condition an immaterial mental subject may or may not satisfy depending on whether it is set up in the right way or not. As long as it has the right active and passive causal powers and there is a human biological organism that also has the right active and causal powers such that that mental subject and that human biological organism stand in the relation of human embodiment, then it is human, and otherwise not. On Merrick's account, where to be human is to become a human biological organism, an immaterial mental subject becomes human by acquiring the right physical properties so that it qualifies as a member of the species of Homo Sapiens. I think you are thinking of humanity in a different way. Perhaps you are thinking of it as a basic kind to which you belong essentially and permanently or not at all. So to think of a divine subject becoming human is for you like thinking of an abstract object becoming concrete or a substance becoming a property. We might almost say, on this picture, to think that something like that could happen just makes no sense.
BV: Let us suppose that your Cartesian substance-dualist scheme is tenable, and that what makes me human is nothing intrinsic to my being a mental subject, but rather my contingently standing in the relation of being embodied by to a human biological organism. It would then follow that I could exist without being human, just as the mental subject who is the Son can exist without being human. It would then be impossible for me to object that, while the Son is accidentally human, Jesus is essentially human. For on your scheme, both are accidentally human.
But this ignores the fact that the Incarnation is not the Son’s assuming of a human body (or biological organism), but the Son’s assuming of a human body-mind complex. How can the Son be identical to the mind of Jesus given the argument presented above?
I hope some of this has been helpful and our exchange is of mutual benefit. I have enjoyed working through your paper and producing this reply.
BV: Your comments are excellent. I only wish I would have had the benefit of them before I submitted my paper for publication.