The Second Night Sam now points out some problems for Gretchen’s view that the bodily identity is personal identity When you wake up in the morning, you know you are the same person, without checking your body to see It seems possible for a person to discover that they have a different body.

These considerations suggest that personal identity consists in psychological continuity. It is neither a material nor mental substance, but a relation that obtains between the times of a person’s life.

Four Dimensionalism A person is extended not just in space, but also time. Each moment of time is a segment, a part of a person’s life. Personal identity depends on a constitution relation that obtains between these different parts. What is the constitution relation?

Sam answers: the Constitution relation is memory. But memory can’t just be an experience, a seeming to remember. It has to be genuine Memory Gretchen thinks this leads to a problem

We need to distinguish genuine from apparent Memory Gretchen: My memory is genuine, if I actually did what I remember myself doing. But if this is right, memory cannot account for personal identity. It leads to a circular definition Personal identity is defined in terms of memory, which is defined in terms of apparent memory and being identical

Dave comes to Sam’s rescue with an example. Dave seems to remember knocking over a menorah. He actually did knock over the menorah. So this example fits G’s definition of a genuine memory BUT it was not a genuine memory. Dave was too young. He thinks he remembers it because he was told the story by his parents

Dave and Sam think the example shows that genuine memory is not apparent memory plus identity Instead it is apparent memory, plus the right sort of causal chain A real memory needs to be caused by the experience remembered, not by something external (such as hypnosis, or a being told a story by other people)

Is survival after death then possible? Sam suggests God could recreate a heavenly Gretchen whose memory experiences are related in the right way with the earthly Gretchen, thereby allowing her survival after death

The duplication problem It is a principle of logic that: If A=B and A=C, then C=B This poses problem for the memory view when we consider God creating TWO causal chains linking the earthly Gretchen to two heavenly Gretchens

Gretchen cannot become two people. But if personal identity was constituted by memory relations, then she can become two people. Just recreate the correct causal chain twice.

Dave responds by changing his view: Personal identity is constituted by memory and the absence of duplication. Thus if God creates one person with Gretchen memories, that person is Gretchen. If God creates two people, neither will be Gretchen

This solves the problem, but it leads to oddities If Dave is right that identity is memory and no duplicates, then my personal identity is determined by something completely separate, extrinsic to me. Whenever God creates a duplicate of a person, that person dies (and another takes their place). Gretchen thinks this is an absurd consequence