Personal identity and tele-transportation

Kristopher asked:

Hi, I am having trouble writing a paper on a philosophy of mind. I am currently in a intro to philosophy class and the question below is the question I am having trouble with. Could you possibly give me some insight on your opinion to the question posed?

Global warming has rendered the continuation of life on Earth impossible. Luckily, we have been able to melt the polar ice caps on Mars which has created the atmospheric conditions necessary to sustain human life. You have no choice but to make the 36 million mile journey to Mars. However, you can choose your method of transport.

One method is tele-transportation. You will step into a scanner here on earth which will destroy your brain and body, while recording the exact states of all your cells. This information will then be transmitted to a replicator on Mars. Travelling at the speed of light, the message will take three minutes to reach its destination. The replicator will create, out of new matter, a brain and body exactly like yours. The person on Mars will look like you, think like you, in fact be indistinguishable from you. He or she will feel as though they have merely fallen asleep on Earth and then woken up on Mars. This method is 100 percent reliable.

The other choice is to go by spaceship. This is very risky and there is a 50 percent chance that the ship will not complete the journey and you will die in transit. But if you do successfully take the spaceship, then your body and brain won’t at any stage have been destroyed.

You must make the choice which you think will give you the best chance of surviving. What does your choice say about your philosophy of mind?

Answer by Peter Jones

Exam questions are not always well thought through and this seems to be a particularly troublesome one. Your choice of a means of transport will tell you nothing at all about your philosophy of mind.

The travel company is telling you that if you teleport to Mars the person on Mars will be indistinguishable from you as you are now, even to YOU. In this case the travel process must transfer your body, brain AND mind. This is not to do with your philosophy of mind, it is a fact told to you by the travel company. Clearly they have discovered that the transfer of the physical aspects of you is sufficient to reconstitute you on Mars, including your mind. This is a condition of the question. So the decision is an easy one. Why risk going by ship?

The problem is, of course, that the question begs the question it purports to ask. It tells you what you are supposed to think. You are told that your mind is transferred with your brain, thus that your mind is entirely a product of your brain. You can’t change the question so the best way to travel is by teleportation, as you have been told, and what you think about philosophy of mind would be irrelevant to anything.

We can, however, doubt the premise of the question, that the transfer of your brain will entail the transfer of your mind. It is an assumption that renders the question toothless. The question tells us only about the examiner’s philosophy of mind. If the intention was to make you consider the relationship between mind and brain then it should have told you that your mind might or might not be the same when you are teleported to Mars. But if you are told that this relationship is such that you will be exactly the same person with 100% certainty then the question becomes uninteresting.

The real question is whether the teleportation of the brain would entail the teleportation of the mind. This could have been asked more clearly, and then the answer would have revealed your opinion.


Answer by Jürgen Lawrenz

I’m not surprised you are confused. I am confused too – although in my case it’s more a matter of wondering what any of this has to do with the philosophy of mind. The question is loaded with a dozen physical and biological fallacies, and on top of this it leaves completely undefined what understanding you or anyone should have of the word ‘mind’.

However, as a courtesy to you, since you spent some time writing it all out, let me give you the two answers from which you can make your choice:

(1) On one level the question is merely a silly metaphor for the Christian doctrine of reincarnation. Take the scientific mumbo jumbo away, affirm your faith and reply ‘yes’ to the proposition that the process of translation is 100% foolproof – as after all, God is in control. The benefit of this approach is, that you avoid the worry of considering the transmigration of souls into successive bodies (which is of course another way to think about it, but also religious).

(2) On another level, i.e. the scientific mumbo jumbo version, the terms in which the question is framed are inadmissable. The very first assumption, that a brain and body can be pulverised and reconstituted, implies the question ‘why can’t we put organic chemistry in a retort and cook up a new life?’ How are you supposed to handle this when no-one else on earth knows the answer? So the question has no philosophical merit. At any rate, it saves me the bother of refuting the other presuppositions.

I hope this helps you out of your troubles, as I’ve reduced your dilemma to a simple choice of two. The first requires you to choose between the Scriptures and nonsense biology as your authority. The other route is flying with the spaceship. This option is not inviting, but at least you know your chances.


Answer by Sam Michaelides

This question is focussing on the philosophical concept of personal identity and, in particular, a psychological continuity criterion of personal identity versus a bodily continuity criterion. For many, intuitively, the psychological continuity criterion (which states that the identity of a person through time is determined predominantly by psychological factors such as memory, experiences, personality and character traits, rather than on other factors, such as bodily continuity) is the preferred basis for personal identity.

Bernard Williams’ famous Reduplication Argument, however, (which links in to the teleportation example) has caused real problems for the psychological continuity criterion. The argument exposes how the criterion permits potentially infinite duplications, which are then, in a sense, competing for identity with the original. However, Williams believes such situations cannot be possible as identity between entities is an intrinsic relation and thus cannot be reliant on facts about any other entities.

Williams’ Argument was first presented in an early essay, ‘Personal identity and individuation’, as an attack on the memory/ psychological continuity account of personal identity. We are introduced to Charles who apparently has all the memories of the famous historical figure, Guy Fawkes. Historians have corroborated his claims, and indicated that other information he has provided would explain a lot that is not currently known; thus it would seem Charles is a good candidate for some incarnation of the long dead terrorist, offering all the criteria that a supporter of the memory criterion of personal identity could wish for in maintaining that Charles is (identical to) Guy Fawkes.

However, Williams then makes the important point that if it is logically possible that Charles undergoes the changes described, it is logically possible that someone else should also simultaneously undergo the exact same changes – enter Charles’ brother Robert. We now have two equally good candidates for identity with Guy Fawkes, but as Williams points out:

“They cannot both be Guy Fawkes; if they were, Guy Fawkes would be in two places at once, which is absurd. Moreover, if they were both identical with Guy Fawkes, they would be identical with each other, which is also absurd. Hence we could not say that they were both identical with Guy Fawkes.” (1973:8)

Williams argues that since it is not possible for both Charles and Robert to be Guy Fawkes, neither can be. Furthermore, since no facts about any other individual can be relevant to the identity relation between Charles and Guy Fawkes, there cannot be identity between them, even in the absence of a competing candidate, such as Robert.

It may be that a defender of a psychological continuity account of identity (as opposed to a theorist relying solely on memory) would not wish to hold that Charles in this situation is (identical to) Guy Fawkes in any case, but considering a more modern example (and one directly related to your question) will help to underline Williams’ point. Let us suppose that a person ‘A’ steps into some teleportation device in a certain place, gets scanned, disintegrated, then his information is beamed to another device in a different location, out of which steps ‘B’ – an exact replica of A with full psychological continuity. Most supporters of the psychological continuity criterion of personal identity would be happy to state that B is (identical to) A.

Williams is arguing the following: There is nothing to stop A’s information being sent to two or more teleportation devices, each of which can recreate the disintegrated A down the last detail; potentially giving us – at the very least – both B and C. Since it is not possible for both B and C to be (identical to) A, neither can be. Furthermore, since identity between A and B cannot depend on anything other than facts about A and B and the relationship between them, the mere possibility of C, D or any other duplicate coming to exist, means there cannot be identity between A and B even if no other duplicate does appear; thus invalidating any theory of identity that would permit such duplicate relations.

Williams’ argument makes clear one very simple point, which can be used against any theory based on psychological continuity – it permits a one-many relation to occur when identity is strictly one-one.

Various refutations and alternative theories have been offered up against Williams’ argument, all which are easy to find on the Internet. One interesting one is given by Robert Nozick, who rejects this intrinsic nature of identity and has thus developed a particular ‘best candidate’ approach (the Closest Continuer theory), which uses competing entities in order to judge identity. Nozick uses examples of artefact identity to show the implausibility of Williams’ arguments and believes his view (which when applied to cases of personal identity heavily favours psychological continuity) is supported by our intuitive responses to identity questions in many situations.

In my view, Williams’ argument does seem to present the psychological continuity theorist with grave problems concerning the necessity of identity and its intrinsic nature. Theories such as Nozick’s, that reject the intrinsicness of identity appear to either violate the necessity and transitivity of identity or force the theorist to accept some absurd consequences to do with the nature of existence. Also even if theories like Nozick’s did not have the problems just mentioned, the potential for countless duplicates and lack of fixed judgement criteria can inevitably lead only to unacceptable indeterminacy.

Personally, however, I would not want to dispense with psychological continuity as possible criterion of personal identity and have suggested in past work that a subscription to this view implies an accepted distinction between human beings and inanimate objects (leaving aside the complications of identity for non-human animals, futuristic robots etc). Once this distinction is accepted, a different notion of identity, which is epistemic and grounded in belief, should be applied in cases involving persons. If this is done we can indeed reject the intrinsicness of identity without it resulting in metaphysically absurd consequences; and thus psychological continuity should not be ruled out as a basis for personal identity simply because it permits one-many relations.

Whether or not all this means you should risk death on the spaceship or be teleported is, of course, entirely up to you…


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