1 00:00:00,370 --> 00:00:09,640 OK, so let's come and look at Locke's views on this. 2 00:00:09,640 --> 00:00:12,670 Locke, more or more or less invented this topic. 3 00:00:12,670 --> 00:00:24,300 And he came up with a discussion that was really impressively sophisticated, given that he was more or less starting from scratch. 4 00:00:24,300 --> 00:00:29,760 He took the view and it's a very reasonable view that the appropriate criterion of identity, 5 00:00:29,760 --> 00:00:38,640 that is what it is that constitutes sameness over time, depends on the kind of thing you're talking about. 6 00:00:38,640 --> 00:00:42,870 So I suppose you've got a single particle of matter. Think of an atom if you like. 7 00:00:42,870 --> 00:00:49,500 But think of an atom not constituted in the way that we think of it now is made up of protons and neutrons and electrons. 8 00:00:49,500 --> 00:01:02,440 Think of a a single, indivisible corpuscle. The kind of thing that Locke or Boyle might have thought or speculated that matter was composed of, 9 00:01:02,440 --> 00:01:07,600 well, the identity of that, at any rate, seems a relatively straightforward matter. 10 00:01:07,600 --> 00:01:13,810 As long as it continues in existence. It remains self identical. 11 00:01:13,810 --> 00:01:18,910 So A and B are the same particle of matter. If there's a continuous history connecting them. 12 00:01:18,910 --> 00:01:26,050 So imagine a particle here at this one part of time and a particle here is a different time. 13 00:01:26,050 --> 00:01:34,430 They have the same particle. If and only if there's a continuous trajectory leading from one to the other. 14 00:01:34,430 --> 00:01:40,420 OK. So that seems nice and straightforward. What about the identity of a body of matter? 15 00:01:40,420 --> 00:01:47,210 Suppose, for example, we have a lump of clay. What is it that constitutes the identity of that? 16 00:01:47,210 --> 00:01:52,820 Well, that depends on the identity of the particles that constituted. It's the same body. 17 00:01:52,820 --> 00:01:58,820 If and only if it's the same collection of particles, even if they're differently arranged. 18 00:01:58,820 --> 00:02:05,930 So if you take a lump of clay and you squash it and move it around, that remains the same lump of clay. 19 00:02:05,930 --> 00:02:11,660 Even though the particles are differently organised, as long as the same particles are there, it's the same lump. 20 00:02:11,660 --> 00:02:17,970 Now that you could raise a query here, what if you take that lump of clay and divide it up? 21 00:02:17,970 --> 00:02:23,970 And the different parts of the lump have completely different histories for quite a long time. 22 00:02:23,970 --> 00:02:31,750 And then they come back together and the lump is reconstituted. Would you still want to say that's the same lump of clay? 23 00:02:31,750 --> 00:02:36,700 I think one isn't so clear on that, you might think that's indeterminate. 24 00:02:36,700 --> 00:02:46,710 But at any rate, in the standard case where the lump all remains together, that's the criterion that Locke thinks we should apply. 25 00:02:46,710 --> 00:02:55,190 Now, there's a problem here and the problem will emerge if you think about what happens as you mould this clay. 26 00:02:55,190 --> 00:02:59,790 You mould this clay. And having done so, what do you find on your hands? 27 00:02:59,790 --> 00:03:05,160 You find that your hands are dirty. Some of the clay has come off in your hands. 28 00:03:05,160 --> 00:03:10,220 Is that still the same lump in? Well, strictly no. 29 00:03:10,220 --> 00:03:15,430 Strictly, no, because it no longer consists of exactly the same particles. 30 00:03:15,430 --> 00:03:20,660 And I think here we can see the influence of what's called a societys argument. 31 00:03:20,660 --> 00:03:28,070 I suspect that this is in the back of Locke's mind. These arguments are very famous, the paradox of the heap. 32 00:03:28,070 --> 00:03:34,460 For example, how many hoops does it? How many grains of sand does it take to make a heap? 33 00:03:34,460 --> 00:03:40,170 Or the paradox of the bold man? OK. A man with just one hair is bald. 34 00:03:40,170 --> 00:03:44,220 Agreed. Just one hair on his head. That's all. 35 00:03:44,220 --> 00:03:52,020 He's bald. Now, suppose you take a man who has an hairs on his head. 36 00:03:52,020 --> 00:03:57,060 And suppose surgically or somehow you added one hair. 37 00:03:57,060 --> 00:04:01,290 Would that be enough to stop him being bald? No, of course not. 38 00:04:01,290 --> 00:04:10,460 One hair can't make the difference. If a man with Inheres is bald than a man within plus one has must be bold to. 39 00:04:10,460 --> 00:04:16,210 Apply that argument iteratively, you get the conclusion that a man with a million has his bold. 40 00:04:16,210 --> 00:04:21,700 So we get the paradox of the bald man. If a man with just one hair is bald and a man with two heads, he's bald. 41 00:04:21,700 --> 00:04:29,020 If a man with two has his bald, then a man with three hairs. And so there's no where to stop. 42 00:04:29,020 --> 00:04:33,050 And this is a major problem with the issue of vagueness. 43 00:04:33,050 --> 00:04:38,420 Vague predicates. All is clearly a vague predicate. 44 00:04:38,420 --> 00:04:41,690 We've got a vague boundary between being bold and not being bold. 45 00:04:41,690 --> 00:04:46,880 And it leads to all sorts of interesting paradoxes and a lot of philosophers, notably, for example, Timothy Williamson, 46 00:04:46,880 --> 00:04:54,200 who's a professor here at New College, have devoted a lot of energy and a lot of debate to trying to sort these things out. 47 00:04:54,200 --> 00:05:03,290 All I want to say here is that I think we can see that issue in the Locke's criterion for the sameness of a lump of matter. 48 00:05:03,290 --> 00:05:10,020 If you allow just one particle to come off that lump and yet it remain the same lump. 49 00:05:10,020 --> 00:05:13,260 Then you can see again, you can iterate. Take another particle off. 50 00:05:13,260 --> 00:05:19,740 Take another one off. Another and another and another. And so on. Or maybe wait while you're moulding this particular piece of clay. 51 00:05:19,740 --> 00:05:26,970 Maybe your moulding another piece of clay as well. And part the little particles from that piece get mixed with this piece. 52 00:05:26,970 --> 00:05:29,630 Where do you stop? 53 00:05:29,630 --> 00:05:39,370 The obvious way to stop is right at the beginning to say actually strictly even losing one particle of play makes it a different lump. 54 00:05:39,370 --> 00:05:44,710 But that can seem overly strict. OK. 55 00:05:44,710 --> 00:05:51,220 What about the identity of physical organisms? Living things. 56 00:05:51,220 --> 00:05:54,300 Well, a plant or an animal isn't just a collection of matter. 57 00:05:54,300 --> 00:06:02,850 We clearly do not want to apply the strict criterion that applies to lumps of matter to organisms. 58 00:06:02,850 --> 00:06:13,010 Locke describes these as an organised organisation of parts in one coherent body partaking of one common life. 59 00:06:13,010 --> 00:06:22,830 So he wants to say that the identity of a living organism over time is constituted by a continuous history of such an organised life. 60 00:06:22,830 --> 00:06:31,830 And as I've said already, it's actually part of the essence of being a living thing, that you are changing over time in systematic ways. 61 00:06:31,830 --> 00:06:38,960 You're eating at excreting and drinking and breathing and all the other things. 62 00:06:38,960 --> 00:06:45,710 So it's actually essential to being a living thing that you are at some points acquiring new matter. 63 00:06:45,710 --> 00:06:52,350 And at other points losing matter. But as long as that's part of a continuous life history. 64 00:06:52,350 --> 00:06:59,530 We can say correctly that there is a single organism. 65 00:06:59,530 --> 00:07:05,710 And likewise, the identity of a man or with a woman. We are living organisms or at least. 66 00:07:05,710 --> 00:07:13,510 It seems that we are. That's a question we might want to raise when we come to consider the identity of persons, 67 00:07:13,510 --> 00:07:27,500 but at least it seems that as men and women, we have an identity of the same kind as a tree or a dog. 68 00:07:27,500 --> 00:07:38,880 Well, maybe an amoeba. Not so clear. Well, let's put that aside for the moment and come to what Locke has to say about personal identity. 69 00:07:38,880 --> 00:07:41,040 Well, a person is a thinking, 70 00:07:41,040 --> 00:07:50,160 intelligent being that has reason and reflection and can consider itself the same thinking thing in different times, which it does. 71 00:07:50,160 --> 00:07:58,110 Only by that consciousness, which is inseparable from thinking and essential to it. 72 00:07:58,110 --> 00:08:08,570 So notice that Locke is drawing a distinction, a very important distinction between a human organism and a person. 73 00:08:08,570 --> 00:08:17,330 A human organism is a living organism like others, but a person is a thinking, intelligent being. 74 00:08:17,330 --> 00:08:24,690 And Locke is here saying that consciousness, which is inseparable from thinking. 75 00:08:24,690 --> 00:08:35,400 Is the crucial issue. So personal identity over time is going to be something like continuity of consciousness. 76 00:08:35,400 --> 00:08:43,050 And that's clearly going to depend on memory. What makes me the same person as myself? 77 00:08:43,050 --> 00:08:57,440 Years ago. Will be some kind of consciousness of continuity, of consciousness mediated by memory. 78 00:08:57,440 --> 00:09:01,710 Now, one important point to make here. 79 00:09:01,710 --> 00:09:11,850 Concerns, locks, forensic perspective on this forensic just means related to law and legal matters and things like dessert and punishment. 80 00:09:11,850 --> 00:09:16,200 Remember that for people of this time in 17th and 18th centuries. 81 00:09:16,200 --> 00:09:21,630 The big concern about personal identity was life after death. 82 00:09:21,630 --> 00:09:31,970 But also during life, our concept of personal identity is very intimately linked up with these sorts of notions. 83 00:09:31,970 --> 00:09:40,840 So it is very natural. Irresistible, indeed, to be concerned about one's own future. 84 00:09:40,840 --> 00:09:44,800 What makes me more concerned about the future? 85 00:09:44,800 --> 00:09:54,640 In 10 years time, say, of this organism as opposed to other organisms or most other organisms, is that that's me. 86 00:09:54,640 --> 00:10:00,510 I'm concerned about my future in a particularly intimate way. 87 00:10:00,510 --> 00:10:04,170 So the notion of personal identity is not just a theoretical notion. 88 00:10:04,170 --> 00:10:08,250 It carries very important practical concerns. 89 00:10:08,250 --> 00:10:16,860 Likewise, if you believe that there's a punishment in the afterlife for people who have been bad or rewards for those who've been good. 90 00:10:16,860 --> 00:10:29,390 Then you're going to see personal identity over the gap between life and death as crucial from the forensic point of view. 91 00:10:29,390 --> 00:10:38,330 Now, put yourself in Locke's shoes. Personal identity, you see as being a very important notion for this reason. 92 00:10:38,330 --> 00:10:45,200 Most previous philosophers have speculated on personal identity as being constituted by a soul. 93 00:10:45,200 --> 00:10:57,010 In fact, they've pretty much taken that for granted. There's an immaterial soul implanted by God, and it's the identity of the soul which matters. 94 00:10:57,010 --> 00:11:05,030 But the trouble with appealing to an immaterial soul or immaterial substance is, first of all, we have no access to it. 95 00:11:05,030 --> 00:11:11,850 It's very unclear that there is any such stuff or if there were, how we would know what there is. 96 00:11:11,850 --> 00:11:21,210 But also, if you think that souls are constituted by immaterial substance, it's not clear that that really solves the problem. 97 00:11:21,210 --> 00:11:26,310 Because think about physical substance and how that plays a role in our life. 98 00:11:26,310 --> 00:11:34,700 Again, we x we eat, we excrete. The physical substance of our bodies is constantly turning over. 99 00:11:34,700 --> 00:11:39,050 Well, let's suppose that we do have souls that are constituted by immaterial substance. 100 00:11:39,050 --> 00:11:46,040 How do we know the same isn't true of them? Maybe the immaterial substance gets turned over at metabolised in some way. 101 00:11:46,040 --> 00:11:52,340 Who knows? So if you end up with personal identity, depending on immaterial substance, 102 00:11:52,340 --> 00:11:57,560 it looks like the result is just going to be complete obscurity, complete ignorance. 103 00:11:57,560 --> 00:12:10,530 You may be able to appeal to religion to get you out of that, but it's going to be an appeal to authority, not to any sort of rational understanding. 104 00:12:10,530 --> 00:12:17,910 An interesting thought experiment. Which brings home the forensic nature of personal identity. 105 00:12:17,910 --> 00:12:26,580 Nice thought experiment the Bern Bernard Williams came up with. Imagine that. 106 00:12:26,580 --> 00:12:36,150 I fall into the hands of a mad scientist again. The mad scientists play a large role in philosophical thought experiments, as you see. 107 00:12:36,150 --> 00:12:43,850 So you and I are taken into this laboratory by the mad scientist. 108 00:12:43,850 --> 00:12:56,060 And we're told that our brains are going to be switched. So my brain is going to be put into your body and your brain is going to be put into my body. 109 00:12:56,060 --> 00:13:03,950 Well, I hope that being a decent human individual, you will be concerned about the future of both. 110 00:13:03,950 --> 00:13:12,170 Of the persons who will result. So would I. Of course, you might be more intimately concerned about one of them than the other. 111 00:13:12,170 --> 00:13:18,200 So which would you be concerned about the more? 112 00:13:18,200 --> 00:13:28,590 My body, your brain, your body, my brain. Well, I think it's natural to identify with the continuity of the brain. 113 00:13:28,590 --> 00:13:33,340 Would you agree? When I wake up. 114 00:13:33,340 --> 00:13:42,010 Off to the operation. Which person will I identify myself with? 115 00:13:42,010 --> 00:13:50,660 I think when I wake up. If her body. 116 00:13:50,660 --> 00:13:57,910 Better than the old one might be quite happy. 117 00:13:57,910 --> 00:14:04,950 But I think it'll be the continuity of the brain is going to be what afterwards seems to matter. 118 00:14:04,950 --> 00:14:08,880 And I think also it will be what previously seems to matter. 119 00:14:08,880 --> 00:14:16,380 I think when I think forward to which of those two individuals I am going to be more intimately concerned about, 120 00:14:16,380 --> 00:14:22,550 it's going to be the continuity of the brain that does it. 121 00:14:22,550 --> 00:14:31,310 Now, again, if we're thinking of things like an afterlife, you can see that there's nothing so simple to hang on to. 122 00:14:31,310 --> 00:14:42,510 It's very difficult to see how you can make sense of this continuity of concern over a complete absence of body. 123 00:14:42,510 --> 00:14:47,670 Locke doesn't want to have to appeal to some kind of immaterial substance to do the job. 124 00:14:47,670 --> 00:14:52,107 So he brings in consciousness as the solution.