Personal Identity and Time Travel
Ehring (Douglas)
Source: Philosophical Studies, Vol. 52, No. 3 (Nov., 1987), pp. 427-433
Paper - Abstract

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  1. Introduction
  2. Divided Consciousness and Multiple Bodies
  3. Physical-Causal Independence
  4. Memory

  1. Introduction
    1. I imagine this paper is high on the hit-list of those who object to the use of TE1s in the philosophy of Personal Identity. It involves three levels of (at least) technological impossibility:-
      1. A double brain-state transfer2
      2. Time travel3, and
      3. Pre-cognition
    2. The purpose of the paper is to rescue the Psychological View4 from the problems of fission5. These problems can in all likelihood be overcome by adopting a perdurantist6 approach to persistence, but many philosophers think this too high a price to pay, and Ehring doesn’t directly mention it.
    3. Ehring’s approach is – to my mind – even more radical and even less acceptable. It is to challenge the non-identity of the “fission products”. These products are usually deemed to be non-identical for (at least) three reasons:-
      1. the lack of shared consciousness,
      2. the lack of a common body, and
      3. the causal independence of the duplicates
    4. Ehring introduces these challenges – he intends to produce counter-examples to the claim that any of these necessarily lead to non-identity – by setting up a standard fission case:
      1. A brain scan of the dying Reagan is performed and a “restore7” of the information is performed onto two “cleared” recipient brains.
      2. Both recipients – according to the PV – are good candidates for being Reagan once the original has died.
      3. Yet because of the logic of PID, neither can be – because both cannot be, and it would be unprincipled to choose just one8 as the continuer.
    5. Ehring wants to reject the major premise in this argument – one that all writers hitherto have agreed on – that the “fission products” are indeed two people and not one, accepted for the three reasons previously given.
  2. Divided Consciousness and Multiple Bodies
  3. Physical-Causal Independence
  4. Memory
    1. Late on in the paper he alludes to Perry’s patching up of the psychological criterion in9 "Perry (John) - The Problem of Personal Identity". See p. 19.

In-Page Footnotes

Footnote 7: Footnote 8: Footnote 9:

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