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PHIL105: The Big Questions Trimester 3 - 2011. What is Philosophy? Using reason & rational argument to answer the big questions The big questions are:

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Presentation on theme: "PHIL105: The Big Questions Trimester 3 - 2011. What is Philosophy? Using reason & rational argument to answer the big questions The big questions are:"— Presentation transcript:

1 PHIL105: The Big Questions Trimester

2 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

3 Topics Week 1: Personal identity Week 2: The good life Week 3: The meaning of life

4 Introduction to Personal Identity PHIL105 – T3, 2011 Lecture 1

5 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

6 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

7 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?

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

9 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

10 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?

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

12 Cyborgs Use technology to keep us alive! PROBLEMS: –Will it ever work? –How will we know?

13 Personal Identity & the Accident Victim Brain damage and amnesia could drastically change what a person is like But, would it change who they are?

14 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?

15 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?

16 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?

17 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?

18 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 in each case (who is the same person?) 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)

19 The elusive ‘I’ Who here thinks they exist? Cogito ergo sum Meditation time!! ??!!?? Lets ‘find ourselves’ Where am ‘I’ ?!?!

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

21 More on Personal Identity PHIL105 – T3, 2011 Lecture 2

22 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?

23 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

24 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

25 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

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

27 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

28 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

29 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

30 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?

31 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

32 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

33 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

34 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?

35 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

36 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

37 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

38 How Visual Fields Really Work

39 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!

40 What ‘Goes With’ What? When asked to point to the picture that ‘goes with’ what they see… Each hand goes for a different picture!

41 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

42 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)

43 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’

44 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

45 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?

46 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

47 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

48 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 are replaced,’ then 50% of that bodies cells are replaced You 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

49 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

50 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)

51 Parfit: 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 cases 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!

52 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!)

53 For Next Time Get ready to discuss: –The Good Life Read: –Singer, Peter (ed.) (1994). Excerpts of Ultimate Good, in Ethics, pp , , Oxford University Press. (Read all except Nozick, pp )


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