Materialism and the Psychological-continuity Account of Personal Identity
Van Inwagen (Peter)
Source: Van Inwagen - Ontology, Identity and Modality, Part II: Identity, Chapter 9, 1997
Paper - Abstract

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Author’s Introduction

  1. I am going to argue that a materialist should not accept a psychological continuity1 theory of personal identity across time.
  2. I will begin by arguing that a materialist cannot consistently admit the possibility of a certain kind of case beloved of the proponents of psychological-continuity theories, so-called bodily transfer cases, and then attempt to generalize the essential point of the argument for this conclusion to show that a materialist should not accept a psychological continuity2 account of personal identity.

  1. I was induced to prioritise this paper because it is addressed in detail in "Baker (Lynne Rudder) - Personal Identity Over Time". While Baker isn’t a supporter of the PV3, she admits that if PVI is correct in his argument in this paper, this would make body transfer metaphysically impossible, presumably a disappointment for those hoping for the resurrection of the body.
  2. PVI argues that the following combination of philosophical beliefs is inconsistent:-
    → Materialism
    → Realism about Human Persons and their endurance over time
    → The possibility of bodily transfer
  3. Whilst Sydney Shoemaker (or any other philosopher) isn’t PVI’s primary target – which is the PV4 – he includes a long quotation from "Shoemaker (Sydney) - Personal Identity: a Materialist Account", which I’ll briefly summarise rather than quote verbatim:-
    1. We’re to imagine a Brain State-Transfer5 device, which records the state of one brain – thereby obliterating it – and imposes it on another.
    2. Philosophers have differed as to whether this amounts to a person ‘changing bodies6’ – whether the procedure is ‘person preserving’ – or whether it involves killing the original person and creating a psychological duplicate of him.
    3. Most people – including me, I might add – are initially inclined towards the latter view, but Shoemaker has a story to tell that he hopes will change their minds.
    4. We’re to imagine a society in which it’s routine for people to go into hospital for a ‘body-change’, which involves a total BST onto the brain of an artificial duplicate of the person’s body. At the end of the process the original body is incinerated. The practices of the society presuppose that the process is person-preserving, so the brain-state donor’s property, debts, spouse, relationships remain as they were.
    5. In such a society, what they mean by Person7 is preserved by a BST.
    6. But – thinks Shoemaker – if they use the term ’Person’ in this sense, then so should we, because all the qualities and social judgements of personhood are preserved.
    7. So, if they think of BST as person-preserving, then so should we.
  4. Now, there’s a lot more to Shoemaker’s case than this, but PVI thinks that most of it is ‘epicycles’ trying to protect the argument against objections, including:-
    1. Reduplication Objections8: where the BST is performed on more than one recipient, and
    2. Branch Line Cases9: where the original BST donor continues to exist.
  5. While PVI thinks Shoemaker is right to address such cases, they will not be his own main concern10 – which is to show that even in the simple case Shoemaker’s position is incoherent. Bodily transfer is inconsistent with materialism.
  6. PVI thinks that Shoemaker’s initial acceptance that most people find bodily transfer difficult to accept11 – and therefore requires argument to convince them – is a huge understatement. Saying that someone is ‘initially inclined’ to doubt that someone can be converted to information12 and transferred from one place to another by fax or letter can be compared with our ‘initial inclination’ to doubt that a statue can be brought to life. Or to ‘tentatively accepting, as a working hypothesis’, that it is impossible to convert a woman into a laurel tree. PVI thinks – and I agree – that it is harder to believe that Shoemaker’s story represents a real possibility than to believe the story of Pygmalion and Galatea or the story of the metamorphosis13 of Daphne because at least in these cases14 we have material continuity between the ‘before’ and ‘after’ states of the central characters.

  7. Before proceeding to his main argument, PVI wants to get a couple of philosophically-important issues out of the way. These are basically complaints about the use of under-described TEs15:-
    1. Firstly, Shoemaker has no interest in the actual biology of human beings.
      • He seems to think it makes sense to imagine the human brain is like a computer disk that can have its state copied about: that it can have a ‘blank’ state and can have information copied onto it.
      • Instead, we might imagine the human brain as being like a city – which, amongst other things, stores and processes lots of information. But it makes no sense to think of New York being transferred to Beijing.
      • PVI talks about how the information in the brain is in fact built up. He briefly contrasts this natural process with the – wicked – idea of growing a brain16 from scratch in a tank. Basically, his line is that in normal development the brain is in continuous interaction with its environment, and without this parts of the brain atrophy or fail to develop; language development is the example. He thinks that a brain grown in a tank would be nothing like a human brain except in basic anatomy.
      • What do I think of all this? I’m in basic agreement. A brain is wired up to interact with a particular body, at a particular time (since bodies change over time), so you can’t just copy the ‘information’ from one to another without ending up with a mismatch. Secondly, information is held based on the number and strength of synaptic connections and – presumably – the number and locations of the neurons so interconnected. To recreate a brain would involve recreating all this lot; to do it would be indistinguishable from – and even more difficult than – a brain transplant. Then, of course, my previous point about mismatch would apply. I doubt it’s metaphysically impossible to recreate such a brain, but I think it’s metaphysically impossible to solve the mismatch problem.
    2. Secondly, while this is even more tangential to his main argument, he’s suspicious of the hypothetical technology of all TEs17 used in the philosophy of PID.
      • Take Teletransportation18 for example. In this case, his objections seem to be technical – he thinks so much Information19 would need to be beamed across that – if the person were to be transported in a reasonable amount of time – as in Star Trek – it would vaporise the receiver of any suitable size. We might quibble about this (given advances in technology – huge bandwidth seems to be possible even currently), so tweaks to the TE20 might be possible (assuming the original objection is valid). PVI does note that there are questions over whether the reconstructed organism is the same as the original, but that’s not his main point here.
      • Returning to BSTs21, he says there are questions from ‘signals theory’ that the transfer of so much Information22, if it were to take place in a short period of time, would similarly – since he intuits that it’s a necessary metaphysical truth that energy is proportional to Information23 content – that this process would melt any electrodes involved. Tweaking the TE24 to take a year – say – would run up against the problem that the Brain25 is a plastic organ presumably changing throughout the procedure. I wasn’t convinced by this either, the individuals involved would presumably be put into deep comas for as long as the process takes.

  8. PVI returns to his main theme. Shoemaker believes:-
    1. Each of us really exists, and
    2. We really persist through time
  9. He wants to show that in the BST26 case, a certain human person would persist in the same way as normal. He has other things to say – ‘epicycles’ – in the “branching” cases and the case where the donor continues to exist. But PVI wants to focus on the simple case here. PVI doesn’t think BSTs27 make any sense, but the part he understands involves nothing more than the transfer of Information28.
  10. So, based on the above, Shoemaker believes that a Person29 can move from one place to another simply on the basis of a transfer of Information30.
  11. When it comes to the puzzle-cases – says PVI – Shoemaker is an anti-realist31. So, in the “Branching” case the one PVI discusses:-
    1. PVI argues in the usual Reduplication Objection32 manner. Neither of the recipients can literally be the donor, as they can’t both be (as33 they are non-identical to one another), and there’s no reason to choose one rather than the other.
    2. But, Shoemaker argues that even in these problem cases an ‘ideally perfect egoist’ might – under certain circumstances – go along with the information transfer option, even at considerable immediate cost: this ‘epicycle’ is picked up shortly. It all sounds a bit like Parfit34.
  12. But, Shoemaker is not an anti-realist about PID in the ‘normal’ BST35 case, which he considers to be ‘person-preserving’.

  13. So, what’s wrong with the above? PVI claims36 that our Intuition37 is to go along with Shoemaker in the simple BST38 case. If one had six months to live, and one’s goal was to continue on as a conscious being as long as possible, then – if it was ‘now or never’ – one would accept a BST39 even though it involved the destruction of one’s brain today. Our Intuitions40 are constitutive of – or at least display features of – our concept41 of Person42.
  14. PVI thinks this argument ‘deeply flawed’. Our Intuitions43 are simply our beliefs, or what makes certain beliefs attractive to us even if we don’t fully accept them. Our beliefs arise from all sorts of sources and can be wrong. Even if most would accept a BST44 as person-preserving, that’s no guarantee that it is. Our egoist might be confused, mistaken or metaphysically misinformed.
  15. PVI now explains why he thinks such people are indeed mistaken.
    1. Well, if you’re a materialist who believes human persons exist you have to ask yourself what material thing you are. It doesn’t really matter for these purposes – it could be – as PVI believes45 – a whole human organism – or it could be a part thereof, such as a brain, cerebral cortex or cerebrum.
    2. Whatever material thing you choose to be – and the argument goes through for any of the alternatives, so PVI takes it that you are a living organism, x – a believer in body transfer must hold that you could become a numerically distinct living organism y if the right sort of information was transferred from x to y (maybe with epicycles such that x has to be destroyed, and the same information isn’t transferred to a third living organism, z.
    3. Put this way, the matter is impossible since if x is not identical to y, it is not possible that x should be identical to y.
    4. PVI spends some time motivating this principle in the case in point. At t1 you are identical to x and – being a material being – are located where x is. At t2, when you are allegedly identical to y, you will be intitled to say that at t1 you were located where x was – but this is not where y was, so you would have been bi-located, which is impossible.
    5. In the above demonstration, PVI invokes Leibniz Law46, which states that if x is identical to y then they share all their non-intensional properties.
    6. PVI goes on to labour the point somewhat – which is basically that you can’t turn one thing into another by the transfer of information because you cannot turn one thing into another by any means whatsoever.
    7. But I can see that Baker47 will object to all this in "Baker (Lynne Rudder) - Personal Identity Over Time" as PVI’s argument doesn’t take into account the CV48 (CWI). I’ll revisit the details when I complete the review of that Chapter.

  16. So, what response does Shoemaker have?
    1. Well, he recognises something of the difficulties, but not – says PVI – their depth. On his account, x and y are the same Person49 but they are not the same animal or human being. Baldly, this sounds rather like Relative Identity50. However, he claims that persons are not strictly identical to Animals51 or Human beings52. We’re referred to "Shoemaker (Sydney) - Personal Identity: a Materialist Account", pp112-114.
    2. Accordingly, human persons ‘share their matter with’ and ‘occupy the same space as’ and ‘have the same non-historical properties as human beings. This does sound rather like the CV53.
  17. … to be continued.

  18. References:-
  19. Acknowledgements:-


In-Page Footnotes

Footnote 6: Footnote 9: Footnote 10: Footnote 11: Footnote 13: Footnote 14: Footnote 16: Footnote 31: Footnote 33: Footnote 36: Footnote 45:

Text Colour Conventions (see disclaimer)

  1. Blue: Text by me; © Theo Todman, 2024
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