Against Personal Identity

8/9/2019 Against Personal Identity

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AGAINST PERSONAL IDENTITY

Parfit: the question: will I be the sameperson tomorrow has no meaningfulanswer.

The argument summarized:

1. Either dualism (Ego Theory) or else

psychological continuity (Bundle Theory)are the correct theories of identity.

2. Dualism is false.

3. The Bundle Theory is incompatible with

survival.

4. Therefore, personal survival is a myth.

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Against dualism: Split brain cases

Hemispheres of Ss brain have beensevered:

S observes a two-coloured screen. Left eye sees red; right eye blue.

S is asked: (1) how many colours do yousee? (2) What colour do you see?

Right hand writes: (1) One. (2) Red. Left hand writes: (1) One. (2) Blue.

Parfit: This shows that there are twostreams of consciousness in one body.

If dualism were true, the soul wouldunite the streams into oneconsciousness.

Dualism must be false.

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Objection

There is only one stream of consciousness:the subdominant hemisphere is notconscious but is subordinated to thedominant one.

Parfit: People have had their dominanthemispheres destroyed.

They are changed but can still talk,move, respond and generally interact.

So, subdominant hemisphere is conscious.

So, there can be disunified streams ofconsciousness.

This contradicts the idea of a unifiedsoul.

Bundle theory is the only way to go.

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Implications of the bundle theory

Teleportation: You are scanned at T1 in S1. You are destroyed. A replica is created at T2 in S1.

Bundle theory: You survive becausepsychological continuity is preserved (in theright, causal way).

Parfit: What if two copies are made?

They cant both be identical to you (2 1).

Conclusion: since each duplicate ispsychologically continuous with you,psychological continuity is not sufficient forpreserving identity

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Against the No-Branching Clause

Suppose that you are beamed somewhere.

You open your eyes, look around, recallthe teleportation and your childhood,and then get on with your mission.

According to the Bundle Theory, yousurvive.

If, however, 10 duplicates were to beteleported to the same room, none would beyou.

How can such an extrinsic fact be what

determines whether you survive?

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Summary

On the Bundle Theory, there are only thefollowing kinds of fact:

Experiences exist. Some are psychologically continuous.

But psychological continuity relates sets ofexperience that are not strictly identical.

So this is possible:

B C D E

A

Neither B, C, D nor E is identical to A.

But if we remove B, D, and E, that cantsuddenly make C identical to A.

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Operations

Teleportation is like an operation whereeach of your cells is replaced by a duplicate.

The above reasoning shows that100% replacement destroys identity.

But do you believe that, for example, 0.1%replacement does not destroy identity?

If so, then you believe that:

There is some critical percentage

between 0.1% and 100% that marksthe boundary between survival anddeath.

Parfit: It is absurd to suppose there is a lineat which removing one cell would destroy

your identity, but not removing that cellwould preserve it.

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Impossible to find

Parfit: Whats more, we could never detectwhere such a line would be.

Say the crucial percentage is 49%. If 50% is replaced, you die. But the 50% replacement is

psychologically continuous with you. So, we could never determine that

s/he isnt you.

Conclusion: We should give up belief insuch a line.

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We are only bundles

Parfit: If the bundle theory is true, then thereis no point trying to find this line.

There is no you, no Ego/substancethat underlies your experiences.

There are only the experiences.

Here is a complete description:

1. John has 50% of his cells replaced.2. Psychological continuity is preserved.3. The continuity has an unusual cause.

If we feel the need to ask: But is the resultreally identical to John?

Then we have ignored the lessons ofthe bundle theory:

There is no further fact of the matterbesides 1-3

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A short way of looking at it

B1: 100% replacement destroys identity.B2: 0.1% replacement preserves identity.

B1 + B2 = critical percentage = absurd.

But B1 is proven by branching cases.

So, must give up B2.

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Lessons of the Bundle Theory

Suppose Q (at T1) and P (at T2) arepsychologically continuous experiences.

Q: Are P and Q part of the same person?

Parfit: What are you asking?

1. Same soul? No: dualism is false.2. Strict identity (P = Q)? No: Leibnizs

Law.3. Psych. Cont.? Yes.

But: #3 may apply to many distinct bundles

of experience: R (at T2), S (at T2), etc. mayall be psychologically continuous with Q.

Okay, but which one is really identical to Q?

Parfit: senseless question: no more facts

other than 1-3.

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Surprising conclusion

1. You and your replica are psych. cont. butnot identical.

2. Your experiences today and tomorroware psych. cont.

Therefore:

3. Future, psychologically continuousexperiences are no more you than isyour replica.

In other words:

There is no connection between youtoday you tomorrow that is not sharedby you and possibly many distantreplicas.

Since there is no survival in the latter case,there is none in the former.

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Final view: Dualism

There are two questions to ask:

1. Conceptual: What is it for P2 at T2 to beidentical to P1 at T1?

2. Evidential: On what grounds do weconclude P2 = P1?

Swinburne: Most writers assume that theanswer to #2 gives us the answer to #1.

These are empiricist theories ofpersonal identity.

They are not satisfactory.

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The story of empiricism

1. BODILYTHEORY Problem : Body gains/loses parts.

2. PSYCHOLOGICALCONTINUITY Problem : Teleportation/Duplication.

3. BRAINTHEORY Problem : Brains can be duplicated as

well.

4. PARFIT: There is no (total) survival.

Problem : How does Parfit know this? It could be that one part of the brain is

the centre of experience (Chisholm). Parfits view needs empirical support

that he doesnt provide.

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Response

Swinburne:

Bodily continuityBrain continuityPsychological continuity

Are all (fallible) evidence of personalidentity.

However, what they are evidence of isdistinct from these criteria.

Personal identity the criteria we use toascribe personal identity.

Okay, but then what is personal identity?

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The story of dualism

Swinburne: Logic alone cant tell us whichset of future experiences I will have.

Thats why the empiricist theories have somany counterexamples.

Perhaps as a matter of fact I will have one

and only one set of future experiences(even in teleportation cases).

There may be empirical doubt as towhich future duplicate is in fact me.

But it doesnt follow that there is no fact

of the matter.

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The mind-body relation

For a body to be my body means:

1. I can move this body directly.

I dont need to do something else first inorder to get my arm to move.

2. Empirical knowledge is gained throughthe body.

What I know about the world is theresult of the worlds effects on this body.

In short: this body is my vehicle of agency inthe world and knowledge of the world.

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Minds are not bodies

But then, it is entirely possible that I findmyself:

1. Able to move another body directly.2. Gaining information via another body.

It is also coherent to suppose a person

becomes disembodied:

Able to move objects in a room directly(not through a body).

Able to know where objects in a roomare without seeing them.

Disembodied survival is logically coherent:

Minds are not necessarily bodies.

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Against verificationism

Swinburne: Body/brain continuity is ourmain evidence of personal identity.

So : I cant describe an actual casewhere memory and bodily continuity arelost but identity remains.

But: only verificationists conclude that lackof evidence = lack of possibility.

So, it remains logically possible that Isurvive without my body and without mymemories.

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The argument for dualism

1. Let:

P = I am conscious and exist in 2007.

Q = my body is destroyed in 2007 (end)

R = I have a soul in 2007

S = I exist in 2008

2. Whatever else is true today, it is logicallypossible that P & Q & S.

(I.e. (x)(P&Q&S&x), where x rangesover states consistent with P&Q)

3. but if ~R, then (P & Q & S) is notpossible.

(I.e. ~(P&Q&S&~R))

Therefore:

4. R

(I.e., ~R is not within the range of x)

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The essence of persons

So, the form (essential properties) of aperson is:

The ability to have consciousexperiences and perform intentionalactions.

But what is it for such an essence at T2 tobe identical to one at T1?

Swinburne:

If S2 at T2 has the same form (thought,intention) as that as S1 at T1.

And S2 is made out of the same stuff asS1.

Then S2 = S1.

(Generalized Aristotelian criteria).

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Mind-body dualism

It follows that we are made up of two kindsof stuff. A person is:

A thinking thing (soul) combined with

A physical body.

What matters for survival is the continuationof the soul.

Souls are not divisible:

All matter takes up space so all mattercan be divided (logically) into smaller

volumes. Souls take up no space so there is no

sense in which they can divide.

So, strict identity is preserved.

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Problems with Dualism

According to dualism ones body, beliefseven personality may change. However:

One survives because the soul continues.

But:

If the soul is not my beliefs, personalityor body, what exactly is it? Whats leftto be me?

Is there room in a scientific worldview

for an immaterial soul?

How can an immaterial substanceinteract with a material one?

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Problems with the argument

Assume (P & Q & S) is possible.

It doesnt follow that this is only possibleif I in fact have a soul.

What follows is that this is only possibleif it is possible that I have a soul.

All Swinburne has shown is that I mighthave a soul, not that I do.

2. Swinburne assumes that whatever else istrue of me, it is possible that I continue toexist without my body.

Why assume this? If ~R is true of me right now, then it may

not be possible that I continue w/o mybody.

So the possibility of (P & Q & S)assumes I have a soul, it doesnt proveit.

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Appendix: survival and the A-/B-seriesdebate

Two views on identity:

Endurance: A person is wholly present ateach moment s/he exists. The personendures by remaining unchanged frommoment to moment (like dualism).

Perdurance: A person is extended in time,composed of temporal parts or stages.These parts are related so as to beunited into a single whole. There is noone part that is wholly present at all

times in a persons life.

Does ones stance on the A-/B-seriesdispute constrain ones position here?

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Temporal parts and the A-series

Argument 1: perdurance is inconsistent withA-time.

1. If X is composed of temporal parts,then there is no time at which all of Xsparts are present.

2. I.e., X cant be wholly present at

different times.3. So, X cant move in time for this

requires all of X to be at T1, then all ofX to be at T2, etc.

Therefore:4. If the perdurance view is right, a

person cant move through time andthe A-series must be false.

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Objections

Objection 1: The perduring whole is presentso long as any temporal part is present.

I.e., when part P1 is present, the personis (wholly) P1; when P2 is present, theperson is (wholly) P2.

Reply: Then there is not one thingpersisting in time, but two things: P1 andP2.

Objection 2: perhaps each part successivelybecomes present.

Reply: then the person is never whollypresent at any time, only a part is.

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Objection 3: Why not say that I am whollypresent so long as part of me is.

E.g. W.W.II. is present if one of itsbattles is; John is present if one of hisparts is.

Then, as different parts becomepresent, I (wholly) move in time

Reply: If part of me is in room A and part inroom B, I am not wholly in either.

So, why say that John (or the war) is?

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Rejoinder: Because time differs from space.If one temporal part is present, we have tosay the whole is presentthe alternative isabsurd:

If the whole is past, then no parts arepresent. If it is future, then no parts arepresent.

So, if a part is present, the whole isneither past nor future.

So, it is present if one part is.

Reply: This proves too much, i.e. it provesthat a whole is past if one part is past:

If W is future, no parts are past.

If W is present, no parts are past.

So, if part is past, then whole is past.

Upshot:

If perdurance view is right, must adoptthe B-series view.

To hold to the A-series, one must adoptthe endurance view.

But

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Can the B-theorist be an endurantist?

Argument 2: No, she cant.1. Assume B-series2. S is (tenselessly) P3. S is (tenselessly) not-P4. So S is P and not-P, which is absurd.

Therefore,5. B-series requires temporal parts to

exhibit the different properties.

Reply: S is (tenselessly) P at T1 and not-Pat T2.

I.e. properties are relations if thesubstance view is right.

This is consistent with B-series.

So, the B-series is consistent with bothendurance and perdurance. The A-seriescan only have endurance.

Is this an advantage for the B-series view(i.e., it rules out less)?

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Relational vs. substantive time

Relational time: time is sets of eventsstanding in temporal relations to each other.

Substantive time: time is a substance thatcontains events.

Argument: substance view + B-series view

= substantive time.

Assume B-time.

Assume S is an enduring substance.

For all time, S first thinks of Plato (eventP) then Descartes (event D).

Assume nothing else exists.

I.e. all history contains is P followed byD.

Every occurrence of P (or D) has exactly the

same temporal relations to everything else.So, there is no way to differentiate them.

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Reply 1: Each is present at a different time.

Problems:

Abandons B-series for A-series

Assumes A-properties occur at differenttimes, and this time might besubstantive (i.e. how differentiatethem?).

Reply 2: Each subsequent P-type event ispart of a different stage of S.

I.e. we individuate Ps by reference toparts of S.

Problem: we have abandoned theendurance view for perdurance.

Conclusion: we need substantive time todifferentiate the different P (D) events.

In other words, different Ps (Ds) are at

different substantive points in time.

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But there is an objection to this:

Maybe the story, as told, is incorrect:

In fact, there are only two events, P thenD (and one substance, S).

Since we cant distinguish them, itfollows that we werent describing auniverse of recurring Ps and Ds.

Rather, we were actually describing auniverse in which S thinks of P then D,and thats it.

There is no need for substantive time forthere are no Ps (Ds) to distinguish.

So, relationalism is saved: it is consistentwith B-time and endurance (we just need tocarefully interpret our stories).

But this isnt the end of the story

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Eternal recurrence

It may be false, but eternal recurrenceseems possible.

I.e., there could be a world in which Pand D repeat infinitely.

So, if we assume S is a substance, and timeis tenseless, we must assume:

Time is substantive.

That is the only way to make sense ofdifferent Ps preceding different Ds.

I.e., so long as eternal recurrence ispossible:

The substance view of persons + B-timeEntail:

Time is a substance.

Is this a weakness of the B-series view?

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Joshua Mozersky

Department of Philosophy

Queens University

Kingston, ON

K7L 3N6

Canada

Tel: 613-533-6000 ext. 77044

Fax: 613-533-6545

[email protected]
http://www.queensu.ca/philosophy/http://www.queensu.ca/mailto:[email protected]://www.queensu.ca/mailto:[email protected]://www.queensu.ca/philosophy/

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