Personal identity

I said a long time ago that the first possibility I want to investigate is that it is my body which gives me my identity.

One theory of personal identity is that it is my body which makes me the same person now as I was fifteen weeks ago - this body is the very same as the one that was before you then.

But I said if I say this I have another question to answer immediately: what is it for this body to be 'the same' as that one?

We have now considered this question. We have not answered it, but we have considered it.

I suggested for consideration two theses - as Terence Penelhum does in the Reader: the mereological principle and the spatio-temporal continuity thesis.

The mereological principle: that a complex thing A can only be the same as another thing B if both are made up of the very same parts.

The spatio-temporal continuity thesis: that a thing A is the same as the thing B if A and B are connected by a continuous path through space-time.

I said that one way of thinking about the Ship of Theseus is to reflect that in this case these two tests point to different conclusions.

Although not everybody agreed, most of us appeared to judge that if the chips were down and you had to choose, the mereological principle was to be embraced.

Does personal identity rest on identity of a body?

Let's now turn to the question of what makes a person Tom the same person as the person Tomasin - the question of personal identity.

I said before this was an important as well as an interesting question, because for example of the question of moral responsibility, and of survival after death.

One influential answer, and one you may find depressing but difficult to resist is: Tom's body. That's to say, Tom is Tomasin if Tom's body is one and the same as Tomasin's body.

Multiple personalities

Think if you will for a moment of what are generally called 'multiple personalities'. There's a film called The Three Faces of Eve which presents one striking real life case: a single body apparently displaying alternately three contrasting characters.

This condition began to figure in the medical literature around the start of the nineteenth century, with doctors prepared to attribute more and more personalities to the same body as the decades passed, until in some quarters of American medicine there are practitioners who are now prepared to attribute well over a hundred different personalities to the same body at different times.

Something is altering in our concept of a personality I think when a number of this sort is countenanced, so I think we stick for our thinking with the Eve-type case, with just a few.

It's perhaps significant that we reach for the term 'personality' in these cases. We don't say there is one body here which happens to be shared by three people. We say shared by three personalities.

But we are talking of something more than one person with violent mood swings or personality shifts. I think the key thing that makes multiple personalities special is that with them each 'personality' fails to 'identify' with the others. Each of Eve's personalities spoke of the others as though they were separate people. It was only other people, notably her psychiatrist, who knew these three personalities were each of them associated with one and the same body.

When you assume a different personality for surfing the net, ordinarily you know what you are doing and in your net personality no less than in your ordinary personality you are aware that it is one person, you, who have the two personalities. That's not multiple personalities in the really interesting sense - though I think it is very interesting in its own right. (Who in their right mind welcomes vidcams? Allowing you to construct a personality of your choice and then to present yourself to the world in those terms is one of the truly new human possibilities the computer has created for us.)

David Bowie's alternative personality was Ziggy Stardust, was it not. We use the phrase 'alter ego'. I'm not sure whether David knew that he had two personalities or whether when he was Ziggy he thought of David as a different person. But if he did, David and Ziggy were two personalities and not just different days of one person's life.

I'm suggesting then that the reason why we don't say of this kind of case there are just two people here, Ziggy and David, is that both are associated (at different times) with one and the same body. Even when they think they are are two people - Ziggy thinking of David as a different person, and David thinking of Ziggy as a different person, we don't go along with this because of the one body. So one thing thing the bodily identity theory of personality identity rules out is more than one person sharing the same body.

In another cultural context, the idea that is reached for when faced with what we describe as 'multiple personality' is 'possession'.

Is it the body of one person that is 'borrowed' by another - another person or 'spirit'? I think it's probably more than this isn't it - it seems that the legitimate owner of the body is still around, thought of as somehow commandeered by a superior force. I'm reminded at this point of Being John Malkovitch, where Malkovitch is still there when there is someone else inside him, but feels pushed around, taken over. Is this like possession?

So though in the Modern world we seem in real life against admitting the possibility of more than one person in somebody else's body, we allow it in films.

Prompt: Some films where a body has multiple tenancy or at least changes hands?

So if identity were carried entirely by the identity of the body, it wouldn't be possible for there to be more than one person in the same body.

Reincarnation

Another possibility that would be banished conceptually if identity of person was carried by identity of body would be a doctrine which can be laughed at quietly or loudly in some circles, but which is taken seriously by millions of course and that is reincarnation.

This is the idea that after I go through the process we call 'death' I launch on another phase of existence - in a different body. And as you know the body you are allocated depends on what you have made of the phase of existence you have just completed. You may return as a beetle if you have not done terribly well, or if you have made a better fist of it as something more comfortable like a badger maybe.

But if my body needed to be spatio-temporally continuous for me to stay the same person, this wouldn't be a possibility. When this body disintegrated my identity would disintegrate too…

Carrying on after death

Which brings us to the darkest implication of the same-body-same-person view: it would rule out any kind of spiritual existence after death. It's not just reincarnation that would be ruled out but continued non-embodied existence of any kind.

Notice of course that orthodox Christian theology insists presumably for something like this reason on the resurrection of the body. Life after death of the person I am, this acknowledges, requires this body to be reconstituted from its scattered components - so that spatio-temporal continuity of body parts at any rate is achieved. (But note what Penelhum says.)

Prompt: What do you think about the possibility of (a) having someone dispossessing you of your body and (b) reincarnation? Find out what your neighbour thinks. Two questions:

1. Are either of these conceivable?

2. Might (a) or (b) actually be on the cards?

Results

We should at least review the alternatives to the theory that body gives us our identity. There are two and a half that I want to put before you: memory, soul and program.

The memory criterion

If I can remember being here 10 weeks ago I am the same person who appeared before you on this awkward spot 10 weeks ago.

"Person A at time T2 is the same as person B at some earlier time T1 if and only if, among the experiences that a person A has at T2 there are memories of experiences that person B had at T1."

John Locke seems to have this in mind. He suggested that it must have to do with your being able to remember being the person with whom it is claimed you are identical.

'For, it being the same consciousness that makes a man be himself to himself, personal identity depends on that only ...' Locke, Essay, Book 2 Chapter XXVII Para 10

PROMPT: Objections to this theory? Suggestions

The non-physical entity theory

This idea trades on the spatio-temporal continuity criterion that was invoked in our discussion of bodily continuity. With bodies it makes sense at any rate to think of the body tracing a continuous path through space and time from where it was to where it is now. Even if the self is a non-physical thing, maybe there is something analogous that would apply?

If we are speaking not of a physical body in space but a non-physical entity, the 'self', what corresponds to 'spatio-temporal continuity'? We shall have to drop the 'spatio'. The suggestion might be that a self at time t1 would be one and the same self at time t2 if it showed continuity through time. This would mean that for identity it would somehow have to be in continuous existence at all times between t1 and t2.

So would you look inside yourselves and see if there is anything like this there?

Prompt: Have a preliminary look now, and I'll ask you to have a bit more of a search in a bit.

'This is the doctrine that in spite of the changingness of our mental lives, there is some hidden core to it that persists unchanged throughout, thus providing a backdrop against which the changes occur." Penelhum, the Reader p.430.

'It follows from Descartes' view of mind that personal identity consists in the continuation of an immaterial substance, a mind or soul.' Woolhouse, The Empiricists, p.99.

"Person A at time T2 is the same as person B at some earlier time T1 if and only if, among the experiences that a person A has at T2 there are memories of experiences that person B had at T1."

Person A at time T2 is the same as person B at some earlier time T1 if and only if A and B have one and the same soul, ie a single nonphysicanonphysical entity which remains the same entity for periods of time, during which the person it belongs to remains the same person.

People who defend this idea often speak of the nonphysical entity here as the soul or spirit. Confusingly they speak sometimes of a person as 'having' a soul and sometimes of the soul as being the person.

People also speak of the soul as I am here defining it as the 'self'. Our true self is, as they understand it, this nonphysical entity we are talking about.

So the view is: person A is the same as person B if and only if A has (or is) one and the same soul as B has (or is).

Let us note though that this says nothing about what it is that makes soul A the same as soul B.

It just says that for person A to be the same as person B A has to have the same soul as B (or to be the same soul as B).

One answer to the question what makes person A the same person as person B is this: having the same body.

This raises the question: well, what is it then that makes body A the same as body B?

What is it that makes person A the same person as person B? Answer: Having the same soul.

And a possible answer to this is: the nonphysical equivalent of spatio-temporal continuity.

There could have been one lion appearing twice or two lions appearing once. And the difference it was suggested was spatio-temporal continuity.

What if we are talking not physical entities like lions, but nonphysical entities like souls? What is the difference between one soul appearing twice and two souls appearing once?

Nice things about the nonphysical entity view

Now that we are thinking of a non-body, you can think of yourself going on when your physical body disintegrates. (But you needn't. Even if you held that you were a non-physical self of this kind you needn't hold that your will live forever. You may hold that the non-physical self passes out of existence when your body does.)

The concept of a non-physical self is helpful in other ways too. You can hold that it comes into existence at a particular time. You are not bound to say it comes into existence when the body comes into existence, for example. If you think you are essentially a physical body (including a tremendously capable brain of course) then you have to hold that you come into existence as your body comes into existence. But if you hold that you are essentially a non-physical body you

can hold that you come into existence at conception, or at birth, or 6 weeks after conception, or when you develop rational thought, or when you become aware, or with the first cuckoo in Spring. All these are conceptual possibilities if you identify self with a non-physical entity.

It also allows you to think of several selves associated with a single body, or of one self moving around from body to body. For example, David Hume might come back in a different form.

If your self is like this, should you be able to see it? - not with your eyes, I mean, but with the inner eye when you reflect or 'introspect'?

If you can't see it, or have any kind of experience of it at all, would this begin to suggest that you shouldn't really be talking about it, that there was something bogus about the idea?

David Hume thought so. He said you ought to be able have some experience of the enduring nonphysical entity that is supposed to be yourself if the idea was to make any sense.

Prompt: Can you find it? Hume's response

It's a sort of difficulty with what they say they see. It asks you to imagine there being not just one continuing self but a succession of shortlived selves. That is, suppose there wasn't just one self in there continuing through time but a very large number of selves succeeding each other rapidly. You look now and see one but it passes out of existence and another one takes its place before you look again.

(b) How would you tell whether it was this that was happening and not one single self continuing through time?

Is there a nonphysical equivalent of spatio-temporal continuity?

The view we are considering is: person A is the same as person B if and only if A has (or is) one and the same soul as B has (or is).

Let us note though that this says nothing about what it is that makes soul A the same as soul B.

It just says that for person A to be the same as person B A has to have the same soul as B (or to be the same soul as B).

One answer to the question what makes person A the same person as person B is this: having the same body.

This raises the question: well, what is it then that makes body A the same as body B?

What is it that makes person A the same person as person B? Answer: Having the same soul.

And a possible answer to this is: the nonphysical equivalent of spatio-temporal continuity.

There could have been one lion appearing twice or two lions appearing once. And the difference it was suggested was spatio-temporal continuity.

What if we are talking not physical entities like lions, but nonphysical entities like souls? What is the difference between one soul appearing twice and two souls appearing once?

The greenfinch illusion

You see a greenfinch at the bird table at 9 o'clock in the morning - a lovely thing. It visits again at 10, and you are even more delighted - you have obviously found a food it really likes. And it comes back for more at 11. Throughout the day your little friend keeps coming back every now and again, feeding chicks on the nest somewhere you suspect. Only it turns out not to be the same bird returning over and over, a special and appreciative friend, but different members of a whole flock of greenfinches that apparently work a district in this way. You feel exploited rather than loved, but there we are. Might anything like this be happening when you look inside yourself and see the inner you as you think? Every time you look inside yourself you see something very similar. You easily conclude that there is one thing there continuing in existence from one observation to the next. But may be not? Maybe there's a flock of selves in the neighbourhood and each is visiting you once.

With the greenfinches, you do some more careful observation, with binoculars, and check out spatio-temporal continuity. You wait for your visitor to fly off and then you keep tabs on it until either it returns or another bird flies in in its place. But with selves you can't do that. The suggestion is that every time you stop being aware of a self another one takes its place. There's no way you can check this out by keeping looking - you can't be aware of the self when you've stopped being aware of it.

Think about the greenfinches then, but the main points to take from this section are:

some people that when they 'introspect' they are aware of the self in the sense of an enduring non-physical entity which is - them,

that some people say they don't find such a thing and

that this means there is something fishy about the idea that there is one.

The Romantic seed-self

One particular version of the self as non-physical entity enduring through time was articulated by the revolutionary Romantic movement at the end of the 18th Century. The Romantics thought of the self as a kind of non-physical seed, planted in the body at the beginning and growing into a fully mature form as a person's life developed. As a kind of seed it was regarded as full of potential, a potential which gradually achieved realization - if all went well. Something like this is with us today perhaps, when we think of education as ideally a matter of encouraging and facilitating individual development.

Clarification: the difference between the memory criterion for personal identity and the thesis that the self is an enduring non-physical entity.

We ought to be clear about the difference between the memory criterion for personal identity and the thesis that the self is an enduring non-physical entity.

According to the memory criterion person A is the same as person B if A can remember the things B remembers.

So if I wake up after an accident and to begin with don't know who I am, and then come across a diary which tells me about things which I remember doing according to this criterion I must be the person who wrote the diary.

This isn't the view that person A is the same as person B if they have one and the same enduring non-physical entity associated with their body. It is the view that what makes A the same as B is A's remembering being B.

The two criteria

(a)Does B have A's memories?

and

(b)Do A and B have one and the same non-physical entity inside them?

are different.

Difficulties of the concept of the self as a non-physical entity

1. It's a mystery

It is claimed that the concept of self as enduring non-physical entity may be buying useful things at the price of unintelligibility, or at least of impenetrable mystery.

For example, if it is non-physical, how does it connect with the physical? If it does, is the law of conservation of mass-energy breached - i.e. the law that unless matter is destroyed or created, the sum total of energy in the universe remains constant ?

But you will have thought about these problems in connection with theories of the nature of the mind.

2. It is not accessible to experience, according to some.

For those people who can't see it: is it a problem that you can't see it? If you can see it, is it a problem that you can't tell the difference between one continuing self and a succession of selves?

3.There is no alternative to the body as the ground for differentiating persons.

You can't give a satisfactory account of how one self can be different from 'others'. By this I am reminding you of the fact that ordinarily we seem tell where one person stops and another person begins by reference to bodies. If there were no bodies, would we be able to tell? We can imagine the supposedly different selves all having access to a mouthpiece. But how would we tell who was speaking? Each time a person spoke they might say this is A speaking, or this is B. The question is how would each of them know what was them and what was not them? Would memory serve? We have already said apparent memories can be false memories.

There might be a world that is exactly like our world except that no one in it is any of us. (They do exactly as we do in their exactly similar world.)

The self as a program

What of the idea that the human being is essentially a program running on the brain?

The same program could run on one or more brains at the same time. This is surely counterintuitive? Identical twins get towards it perhaps. Do they have any tendency to judge that they are just the one person?

The program could run on another machine when the present brain got dysfunctional.

If we are connectionist computers maybe the 'program' couldn't run on anything but an identical machine? Would this explain why we haven't encountered a problem so far? - haven't encountered a case where a person convincingly identifies with two bodies?

Fallen off the end

Jekyll & Hyde

The original novel is by Robert Louis Stevenson, published in 1886. Dr Jekyll has the idea of splitting 'the two sides' of human nature' into two bodies, I think with the idea that he could indulge in debauchery without it being held a against him. He would do this by turning into another person, Mr Hyde, at night, having fun, and turning back again into the morally irreproachable Dr Jekyll for the daylight hours. (A strong echo of the Vampire theme.) He says his idea is to do this by decanting his dark nature into a different body for the night time indulgence, but from what we can see in the film - and in the novel of course - is spatio-continuity of body preserved.

The clip comes from the 1920 film, with actor John Barrymore presenting a tour de force which established him as one of the greatest actors of the silent screen, as without modern tricks of cinematography - and with very little in the way of make-up - he transmogrifies before your very eyes.

We open I think in the Carlton, as it was in the 1920s, then as now a wide highway into the dark.

[Clip showing discussion of project, transformation of Jekyll into Hyde and back again. Dr Jekyll and Mr Hyde, Director John S. Robertson, UK, 1920.]

Introduction to Philosophy