PHIL105: The

Big

Questions

Trimester 3 - 2011

What is Philosophy?

• Using reason & rational argument to answer the big questions • The big questions are: – The very important ones – Hard to answer even when we have all or most of the relevant facts

Introduction to Personal Identity

PHIL105 – T3, 2011 Lecture 1

Personal Identity

• Who am I?

• What makes me the same person through time?

• What happens to

me

if I’m copied?

• What about people who have their brains chopped in half!?!

• Hard questions, even if we have all of the facts

Terminology

• Numerical identity – A (literally) unique thing • Qualitative identity – Looks, feels, tastes (etc) identical • Essential properties – Required for numerical identity • Accidental properties – Can change without affecting numerical identity

Personal Identity & the Afterlife • It can comfort us to think that our loved ones live on somehow after death • But what would that really entail?

Reincarnation

• You are reborn into a new body after death • PROBLEM: Reincarnations don’t seem to be the same person

Resurrection

• You (and your body) come back to life after you die • PROBLEMS: – Need an earth-like place to go to – If we’re recreated exactly the same, we’ll just die again – Some of your atoms will be part of other organisms

Soul Liberation

• When we die, our soul leaves our body to live on somewhere else • PROBLEMS: – What, exactly, is a soul?

– What would your soul be like?

– Is a soul just the hard drive that our memories, beliefs, and personality are written on to?

– Is your soul without your body really you?

Cryogenics

• Being frozen until medical advances can fix all your ailments • PROBLEMS: – Technological risk – The brain may be too damaged – Ice-cream headache

Cyborgs

• Use technology to keep us alive!

• PROBLEMS: – Will it ever work?

– How will we know?

Personal Identity & the Accident Victim • Brain damage and amnesia could drastically change what a person is like • But, would it change

who they are

?

COMINS

• Continuity of the Mental Is Necessary for Survival • VERDICT: Mr Edward’s son has

not

survived the accident • PROBLEM: – How much and what type of ‘the mental’ has to continue and how must it continue?

CEBINS

• Continued Existence of the Body Is Necessary for Survival • VERDICT: Mr Edward’s son

has

survived the accident • PROBLEM: – This may be necessary, but is it

sufficient

for a person to survive?

CESINS

• Continued Existence of the Soul Is Necessary for Survival • VERDICT: Mr Edward’s son

has

survived the accident • PROBLEM: – If it’s not the body or the mental… what, exactly,

is

the soul again?

Summary – What Makes Us Survive?

• Continuation of mental • Continuation of body • Continuation of soul • A combination • Has Martha’s Mum survived?

• Has Edwards’ son survived?

• Maybe we don’t survive?

Philosophy Clinic: How to Argue that a Theory is the Best Theory • Explain the main theories and their main strength • Apply the theories to real and whacky examples • A good theory will give

an answer

same person?) in each case (who is the • The best theory will give

the right answer for a good reason in most of the cases

• Good reasons for right answers are generally consistent with our reflected-upon intuitions • But you can also explain why some particular intuitions are wrong (and your theory is right)

The elusive ‘I’ • • Who here thinks they exist?

Cogito ergo sum

• Meditation time !! ??

• Lets ‘find ourselves’ • Where am ‘I’ ?!?!

For Next Time

• Read: – Law, Stephen: Brain Transplants, ‘Teleportation’ and the Puzzle of Personal Identity – Parfit, Derek: Divided Minds and the Nature of Persons

More on Personal Identity

PHIL105 – T3, 2011 Lecture 2

Personal Identity

• We want our theory to provide answers to questions like these: • What makes me

me

?

• What makes me the same person through time?

Terminology

• Numerical identity – A (literally) unique thing • Qualitative identity – Looks, feels, tastes (etc) identical • Essential properties – Required for numerical identity • Accidental properties – Can change without affecting numerical identity

Sci-Fi Disclaimer

• The following ‘whacky’ thought experiments may never be possible in real life – But, then again, they might!

• Regardless, a good theory of personal identity should be able to answer theoretically possible as well as actually possible problem cases

Animal Theory

• In essence, each person is a living animal • What essentially makes me me through time is that I am

the very same living creature

as the one in the photos

Brain Transplant Case • A brother and sister have their brains swapped while they sleep one night • Problem for the Animal Theory

Brain Theory

• In essence, each person is their unique living brain • What essentially makes me me through time is that I have

the very same brain

as the ‘me’s in the photos

Brain Recorder Case

• This device re-splices the existing brain bits so that a pre-recorded personality (etc) can be downloaded into the (same) old brain • Problem for the Brain Theory

Stream Theory

• AKA: Psychological Continuity Theory • In essence, each person is (the right kind of) continuation of psychological properties • E.g. What

MIGHT

essentially makes me me through time is that my memories are psychologically continuous

The Reduplication Case

• This device makes perfect copies of anything put in cubicle A (in c. B) but the original is vaporized • A new model also makes a duplicate in cubicle C • Problem for the Stream Theory?

Modified Stream Theory

• In essence, each person is (the right kind of) continuation of psychological properties • Except when two or more people are psychologically continuous (in the right kind of way) from one person – In which case,

none

of those later people are the same person as the original person

The Duplicator Gun Case

• This device makes a perfect copy of anything shot with it but it doesn’t destroy the primary target • Problem for the Modified Stream Theory

They All Seem Wrong!

• The Animal Theory – Gets the brain transplant and recorder cases wrong • The Brain theory – Gets the brain recorder case wrong • The Stream Theory (AKA the Psychological Continuity Theory) – Gets the reduplication and duplicator gun cases wrong • The Modified Stream Theory – Gets the duplicator gun cases wrong

The Teletransporter Case

• You have been ‘teletransporting’ to work (on a very distant planet) for 3 years • You are at work when you are informed that the ‘teletransporter’ really works like the reduplicator (it copies & kills you) • Do you get in and ‘teletransport’ home? Why? Why not?

Divided Minds and the Nature of Persons • Derek Parfit • Split-brain cases tell us something interesting about personal identity • There are no ‘persons’ in a split brain case • But there were no ‘persons’ before the brain was split either

Why Chop Your Brain in Half?

• Suffers of severe epilepsy had their corpus callosum chopped in half to prevent seizures spreading across hemispheres • This means that the two halfs of the brain cannot communicate directly with each other • The resulting body acts as normal in most cases and suffers from less debilitating seizures

The Experiments

• Left hemisphere controls right eye & hand (& speech in right-handers) • Using a special technique, each hemisphere was exposed to a different stimuli • Each hand responded as though there is a separate stream of consciousness in each hemisphere

More Info on the Actual Split-Brain Experiments • A picture is flashed in the left visual field (for a right-hander) so fast that the right eye can’t see it, but the left eye can.

• When asked, the person says they couldn’t see the picture • But the ‘locked-in’ right hemisphere

did

see it!

What ‘Goes With’ What?

• When asked to point to the picture that ‘goes with’ what they see… • Each hand goes for a different picture!

Does Each Hemisphere Know about the Other One?

• They seem to ignore or be unaware of each other • Before the op. patients can name objects on both sides, but only on one side after the op.

• Interestingly, they don’t complain about the loss

The Ego Theory

• What essentially makes me me through time is that all of the ‘me’s are the same

subject of experiences

(ego) • What unites the many experiences I have had in my life is that

I was the one having them all

• The Cartesian View is an example of this (my ego is my soul)

The Bundle Theory

• We cannot explain our survival through time by referring to a ‘person’ – Because no ‘person’ (subject of our experiences) exists!

• There are just bundles of mental states (experiences) tied together by the causal relation of memory (experiencing remembering previous experiences) • We call these bundles ‘lives’

The No Self View

• Buddha was the first bundle theorist • His No Self View is a type of bundle theory • People have ‘nominal existence’ (we sometimes talk as if they exist), but only the parts that make them up really exist

Parfit: What We Believe Ourselves to Be • Science tells us that: – There is

no

evidence for the Ego Theory – There

is

evidence for the Bundle Theory • Most of us believe something like the Ego Theory to be true • Unfortunately, most of us hold false beliefs about who we are!

• Me: But

does

science tell us that?

Replacing Your Cells Case

• A high-tech alien is going to replace some of your cells with identical replicas (all at once) • If it changes 1% of your cells, are you the same person?

• What if it changes 100% of your cells?

• There

are

answers to these qns

How We are Not What We Believe • How could we even know if 49% or 50% (or whatever) replaced cells is the right place for the line? • It is implausible that a few cells will make the difference in the Replacing Your Cells Case • But that is what our natural beliefs/intuitions force us to say!

• Therefore, we should embrace the Bundle Theory

Bundle Theory Applied • When applied to all of the cases, the Bundle theory rejects the question, ‘what happens to

you

?’ • The Bundle Theory can explain what happens, but it doesn't refer to persons (because they don’t really exist) • • If ‘50% of

your cells bodies

are replaced,’ then 50% of cells are replaced

that You

don’t end or survive because

you

there in the first place!

were never • These cases only raise worries because we don’t properly understand the nature of persons

PARFIT: Split-Brain Cases and the Ego Theory • The Ego Theory says that all of the experiences in the split-brain case are being had by the one ego/person (but in 2 streams) • The Ego Theory is wrong because it ignores the disunity between the two streams of consciousness • The ego can’t just split in two – Because it is supposed to be the one unique persisting essential element of a person

PARFIT: Split-Brain Cases and the Bundle Theory • On the Bundle Theory, bodies normally have an awareness of having several different experiences at any one time – There is no ‘I’ (an independently existing & persisting thing) required for the explanation • In the split-brain case, there are two separate states of awareness of experiences – But neither of those states is a unique, independently existing & persisting ‘I’ (they don’t exist)

Parfit: Split-Brain Cases 1

• While cases

both

the Ego Theory and the Bundle Theory can explain our normal awareness of experiences… • Only the Bundle Theory provides a good explanation for the split-brain • Combined with the lack of scientific evidence for the Ego Theory, we should accept the Bundle Theory • Which means that our belief in our persisting ego/self/I is false!

Parfit: Split-Brain Cases 2 • When someone’s brain is divided, two streams of consciousness are created • Neither of the streams is the same person as the original • But, this is just like ordinary survival!

– We are just bundles of mental states tied together by remembering what the previous experiences were like – So, with every new experience, who we are changes (our old numerical identity dies!)

For Next Time

• Get ready to discuss: – The Good Life • Read: – Singer, Peter (ed.) (1994). Excerpts of Ultimate Good, in

Ethics

, pp. 199-205, 211-242, Oxford University Press. (Read all except Nozick, pp. 228-229)