Friday, June 18, 2021

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.


Wes said...

I am not well read on theories of personal identity or the memory theory in particular, and I'm writing just as a lay Christian and self-studied Thomist interested in the topic... Still, it seems to me that since Christ is a Divine Person, and that the divine nature and human nature are united in one suppositum, the "memory" (If we can call it that) of the person of the Son is sufficient for the personal identity of Christ in the Incarnation (as the Divine Person of the Son). Even if we suppose for the sake of argument that the human memory is lost through amnesia, that would only be through the human nature and not the Divine Nature. The Divine Nature would still know all of the lost human knowledge, and this would not be in the same way he knows the knowledge of other people, insofar as the human knowledge of Christ personally belongs to the Divine Person, rather than is just something known by the Divine Person.

Wes said...

Though I suppose I may be showing my ignorance of the memory theory of personal identity in the above comment, as I'm putting the personal identity before the memory, rather than basing the personal identity on the memory. I'm guessing that may be my issue.

Alexander R Pruss said...


I don't think it's right to say that the divine mind of Christ *remembers* what happened to Christ in his humanity. But if it does, it seems so does the divine mind of the Father, since there is only one divine mind in the Trinity, which by the memory theory would lead to the heretical conclusion that the Father is the same person as the Son.

William said...

I think that Locke's memory identity theory could be modified: my identity as a person A needs to be based not just on having the memories of experience of person A but having the memory of _actually being person A_ (during those remembered experiences). So if our perfect telepath G comes to know the memories of A they would normally be tagged, so to speak, as being A's memories when they are part of G's memory.

There is I believe some evidence in humans that we 'tag' our memories of dreams differently than memories of actual events.

Alexander R Pruss said...


Yes, there is a kind of from-the-inside first-personish quality to the memories that are relevant to the theories of personal identity. I don't know, though, whether one has this kind of from-the-inside quality when one has two minds, and is talking about what one mind knows of the other mind's activity, as is the case on an orthodox view of the Incarnation.

William said...

Dr. Pruss:

The meta-tagging feature of human memories is what prevents some of the problems you raise. If

a. the human Jesus has a small finite subset of the previous memories, but tagged as his own

b. the God-nature version would have the human Jesus memories, partial as they would have been, yet, I suppose, tagged as self

c. Other, omniscient-enough entities would know the memories but tag them as not-self memories

Alexander R Pruss said...

But the Father, Son and Holy Spirit each have the numerically same divine mind.