2What is Philosophy?Using reason & rational argument to answer the big questionsThe big questions are:The very important onesHard to answer even when we have all or most of the relevant facts
3Topics Dan Week 1: Personal identity Week 2: The good life Week 3: The meaning of lifeDan
4Introduction to Personal Identity PHIL105 – T3, 2011 Lecture 1
5Personal 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
6Terminology Numerical identity Qualitative identity A (literally) unique thingQualitative identityLooks, feels, tastes (etc) identicalEssential propertiesRequired for numerical identityAccidental propertiesCan change without affecting numerical identity
7Personal Identity & the Afterlife It can comfort us to think that our loved ones live on somehow after deathBut what would that really entail?
8Reincarnation You are reborn into a new body after death PROBLEM: Reincarnations don’t seem to be the same person
9Resurrection You (and your body) come back to life after you die PROBLEMS:Need an earth-like place to go toIf we’re recreated exactly the same, we’ll just die againSome of your atoms will be part of other organisms
10Soul Liberation When we die, our soul leaves our body to live on somewhere elsePROBLEMS: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?
11Cryogenics Being frozen until medical advances can fix all your ailmentsPROBLEMS:Technological riskThe brain may be too damagedIce-cream headache
12Cyborgs Use technology to keep us alive! PROBLEMS: Will it ever work? How will we know?
13Personal Identity & the Accident Victim Brain damage and amnesia could drastically change what a person is likeBut, would it change who they are?
14COMINS Continuity of the Mental Is Necessary for Survival VERDICT: Mr Edward’s son has not survived the accidentPROBLEM:How much and what type of ‘the mental’ has to continue and how must it continue?
15CEBINS Continued Existence of the Body Is Necessary for Survival VERDICT: Mr Edward’s son has survived the accidentPROBLEM:This may be necessary, but is it sufficient for a person to survive?
16CESINS Continued Existence of the Soul Is Necessary for Survival VERDICT: Mr Edward’s son has survived the accidentPROBLEM:If it’s not the body or the mental… what, exactly, is the soul again?
17Summary – What Makes Us Survive? Continuation of mentalContinuation of bodyContinuation of soulA combinationHas Martha’s Mum survived?Has Edwards’ son survived?Maybe we don’t survive?
18Philosophy Clinic: How to Argue that a Theory is the Best Theory Explain the main theories and their main strengthApply the theories to real and whacky examplesA good theory will give an answer in each case (who is the same person?)The best theory will give the right answer for a good reason in most of the casesGood reasons for right answers are generally consistent with our reflected-upon intuitionsBut you can also explain why some particular intuitions are wrong (and your theory is right)
19The elusive ‘I’ Who here thinks they exist? Cogito ergo sum Meditation time!! ??Lets ‘find ourselves’Where am ‘I’ ?!?!
20For Next TimeRead:Law, Stephen: Brain Transplants, ‘Teleportation’ and the Puzzle of Personal IdentityParfit, Derek: Divided Minds and the Nature of Persons
21More on Personal Identity PHIL105 – T3, 2011 Lecture 2
22Personal IdentityWe want our theory to provide answers to questions like these:What makes me me?What makes me the same person through time?
23Terminology Numerical identity Qualitative identity A (literally) unique thingQualitative identityLooks, feels, tastes (etc) identicalEssential propertiesRequired for numerical identityAccidental propertiesCan change without affecting numerical identity
24Sci-Fi DisclaimerThe following ‘whacky’ thought experiments may never be possible in real lifeBut, 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
25Animal 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
26Brain Transplant CaseA brother and sister have their brains swapped while they sleep one nightProblem for the Animal Theory
27Brain 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
28Brain Recorder CaseThis device re-splices the existing brain bits so that a pre-recorded personality (etc) can be downloaded into the (same) old brainProblem for the Brain Theory
29Stream Theory AKA: Psychological Continuity Theory In essence, each person is (the right kind of) continuation of psychological propertiesE.g. What MIGHT essentially makes me me through time is that my memories are psychologically continuous
30The Reduplication Case This device makes perfect copies of anything put in cubicle A (in c. B) but the original is vaporizedA new model also makes a duplicate in cubicle CProblem for the Stream Theory?
31Modified Stream Theory In essence, each person is (the right kind of) continuation of psychological propertiesExcept when two or more people are psychologically continuous (in the right kind of way) from one personIn which case, none of those later people are the same person as the original person
32The Duplicator Gun Case This device makes a perfect copy of anything shot with it but it doesn’t destroy the primary targetProblem for the Modified Stream Theory
33They All Seem Wrong! The Animal Theory The Brain theory Gets the brain transplant and recorder cases wrongThe Brain theoryGets the brain recorder case wrongThe Stream Theory (AKA the Psychological Continuity Theory)Gets the reduplication and duplicator gun cases wrongThe Modified Stream TheoryGets the duplicator gun cases wrong
34The Teletransporter Case You have been ‘teletransporting’ to work (on a very distant planet) for 3 yearsYou 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?
35Divided Minds and the Nature of Persons Derek ParfitSplit-brain cases tell us something interesting about personal identityThere are no ‘persons’ in a split-brain caseBut there were no ‘persons’ before the brain was split either
36Why Chop Your Brain in Half? Suffers of severe epilepsy had their corpus callosum chopped in half to prevent seizures spreading across hemispheresThis means that the two halfs of the brain cannot communicate directly with each otherThe resulting body acts as normal in most cases and suffers from less debilitating seizures
37The ExperimentsLeft hemisphere controls right eye & hand (& speech in right-handers)Using a special technique, each hemisphere was exposed to a different stimuliEach hand responded as though there is a separate stream of consciousness in each hemisphere
39More 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 pictureBut the ‘locked-in’ right hemisphere did see it!
40What ‘Goes With’ What?When asked to point to the picture that ‘goes with’ what they see…Each hand goes for a different picture!
41Does Each Hemisphere Know about the Other One? They seem to ignore or be unaware of each otherBefore 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
42The Ego TheoryWhat 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 allThe Cartesian View is an example of this (my ego is my soul)
43The Bundle TheoryWe 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’
44The No Self View Buddha was the first bundle theorist His No Self View is a type of bundle theoryPeople have ‘nominal existence’ (we sometimes talk as if they exist), but only the parts that make them up really exist
45Parfit: What We Believe Ourselves to Be Science tells us that:There is no evidence for the Ego TheoryThere is evidence for the Bundle TheoryMost of us believe something like the Ego Theory to be trueUnfortunately, most of us hold false beliefs about who we are!Me: But does science tell us that?
46Replacing 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
47How 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 CaseBut that is what our natural beliefs/intuitions force us to say!Therefore, we should embrace the Bundle Theory
48Bundle Theory AppliedWhen 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 are replaced,’ then 50% of that bodies cells are replacedYou don’t end or survive because you were never there in the first place!These cases only raise worries because we don’t properly understand the nature of persons
49PARFIT: 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 consciousnessThe ego can’t just split in twoBecause it is supposed to be the one unique persisting essential element of a person
50PARFIT: Split-Brain Cases and the Bundle Theory On the Bundle Theory, bodies normally have an awareness of having several different experiences at any one timeThere is no ‘I’ (an independently existing & persisting thing) required for the explanationIn the split-brain case, there are two separate states of awareness of experiencesBut neither of those states is a unique, independently existing & persisting ‘I’ (they don’t exist)
51Parfit: Split-Brain Cases 1 While 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 casesCombined with the lack of scientific evidence for the Ego Theory, we should accept the Bundle TheoryWhich means that our belief in our persisting ego/self/I is false!
52Parfit: Split-Brain Cases 2 When someone’s brain is divided, two streams of consciousness are createdNeither of the streams is the same person as the originalBut, this is just like ordinary survival!We are just bundles of mental states tied together by remembering what the previous experiences were likeSo, with every new experience, who we are changes (our old numerical identity dies!)
53For Next Time Get ready to discuss: Read: The Good Life Singer, Peter (ed.) (1994). Excerpts of Ultimate Good, in Ethics, pp , , Oxford University Press. (Read all except Nozick, pp )