1 00:00:10,840 --> 00:00:20,890 When Descartes says, I have a clear understanding of myself as something that thinks and need not be extended, 2 00:00:20,890 --> 00:00:31,360 all that we should allow him is that for all he knows, he is something that thinks and isn't extended from that. 3 00:00:31,360 --> 00:00:43,110 It doesn't follow that he actually is something that thinks and isn't extended. 4 00:00:43,110 --> 00:00:48,630 So Descartes arguments for dualism are not actually particularly strong ones. 5 00:00:48,630 --> 00:00:55,680 If we draw this this clear distinction between epistemology and metaphysics, we refuse to draw inferences from what? 6 00:00:55,680 --> 00:00:59,880 From the fact that we simply have doubts or do not know things. 7 00:00:59,880 --> 00:01:05,490 Then it's hard to get to substance dualism. 8 00:01:05,490 --> 00:01:11,460 There are also some major problems for Cartesian dualism. One of them a famous problem. 9 00:01:11,460 --> 00:01:20,370 How can two such distinct substances interact at all? A problem that's very often thrown at Descartes. 10 00:01:20,370 --> 00:01:26,580 If I consist of mind and body and the mind is purely mental, it thinks. 11 00:01:26,580 --> 00:01:35,610 But it's not extended and the body is purely extended and doesn't think, how can the two ever come into contact with each other? 12 00:01:35,610 --> 00:01:43,800 Seems very hard to understand. Now, this is a real problem for Descartes because Descartes thinks causation is ultimately intelligible. 13 00:01:43,800 --> 00:01:47,850 He thinks we ought to be able to make sense of causation as, for example, 14 00:01:47,850 --> 00:01:53,460 when he says that any calls must have as much perfection or reality as its effect. 15 00:01:53,460 --> 00:02:01,810 He's claiming to have an insight into how things cause other things. 16 00:02:01,810 --> 00:02:07,870 But if we take David Hume's view of causation, then the position is very different. 17 00:02:07,870 --> 00:02:17,800 Remember, David Hume came in the wake of people like Newton and Berkeley, and Newton had said when it came to gravitation, sure, we can't understand. 18 00:02:17,800 --> 00:02:27,340 We can't make intelligible why one object attracts another with a false inversely proportional to the square of the distance. 19 00:02:27,340 --> 00:02:34,030 But when we look at the way things work in the world, it turns out this is what happens. 20 00:02:34,030 --> 00:02:39,310 And Hume generalise that and said quite generally, even with billiard balls, actually, 21 00:02:39,310 --> 00:02:44,170 when you think about one billiard ball bashing into another, it's very familiar. 22 00:02:44,170 --> 00:02:48,970 So it has that feeling of naturalness about it because it's familiar. 23 00:02:48,970 --> 00:02:54,220 But if you put yourself in the position of Adam, the first man who's never seen billiard balls before, 24 00:02:54,220 --> 00:03:06,400 he would be as mystified by that as we are mystified by gravity. If you think causation just ultimately is a matter of one thing following another, 25 00:03:06,400 --> 00:03:12,910 what we call law like connexion, then why shouldn't there be law like connexions between mind and body? 26 00:03:12,910 --> 00:03:17,860 So there's a bit of a sort of nice irony here that that Hume, 27 00:03:17,860 --> 00:03:24,520 who have all these four lost the philosophers of this period, is probably most opposed to Descartes. 28 00:03:24,520 --> 00:03:27,640 Actually, if you take a human view of causation, 29 00:03:27,640 --> 00:03:37,270 what looks like a really serious problem for Descartes actually goes away, doesn't actually go away completely. 30 00:03:37,270 --> 00:03:43,510 There is a genuine issue here about how you would even try to formulate the sorts 31 00:03:43,510 --> 00:03:49,150 of laws that might hold between a mental substance and a physical substance, 32 00:03:49,150 --> 00:03:52,240 even if you don't go with them. 33 00:03:52,240 --> 00:03:58,570 The problem of intelligibility, even if you don't demand that the causal laws be intrinsically intelligible or natural, 34 00:03:58,570 --> 00:04:10,240 trying to formulate any sorts of laws that you might have to connect physical phenomena with mental phenomena is quite a challenge. 35 00:04:10,240 --> 00:04:20,200 Another problem commonly thrown at dualism hinges on the causal closure principle of the causal closure of physics. 36 00:04:20,200 --> 00:04:26,260 The idea of this is that only physical events can cause physical events. 37 00:04:26,260 --> 00:04:32,680 So physics is causally closed in the sense that if you want to look for an explanation of any physical phenomenon, 38 00:04:32,680 --> 00:04:38,750 you have to look at physical things. 39 00:04:38,750 --> 00:04:48,710 Now, it's often said this is a major problem for Cartesian dualism, because if you're a dualist, then it looks like you have to deny causal closure. 40 00:04:48,710 --> 00:04:53,300 Why? Well, because mental events are causing physical events all the time. 41 00:04:53,300 --> 00:04:59,150 I choose to raise my arm. That's a mental choice. And yet it has a physical effect. 42 00:04:59,150 --> 00:05:08,450 But if the behaviour of my arm is entirely determined by physical causes, what room is there for a distinct mental cause? 43 00:05:08,450 --> 00:05:18,760 How can it be some other substance, some mental substance influencing the behaviour of this physical substance? 44 00:05:18,760 --> 00:05:27,670 But in fact, I don't think the causal closure principle is nearly as worrying for for dualism, 45 00:05:27,670 --> 00:05:32,020 as many think, because the question is what basis do we have for believing it? 46 00:05:32,020 --> 00:05:37,840 Why should we believe that physics is closed in that way? 47 00:05:37,840 --> 00:05:46,960 And we do these experiments in the laboratory, all sorts of very clever experiments that measure things to fantastic precision. 48 00:05:46,960 --> 00:05:52,090 Sure, there we might find that everything is explicable in physical terms, 49 00:05:52,090 --> 00:05:59,620 but nobody's ever tried to do any sort of realistic experiment on what's actually going on in a human brain when we think if it were, 50 00:05:59,620 --> 00:06:04,510 in fact the case that there was an immaterial substance there influencing how the atoms move. 51 00:06:04,510 --> 00:06:13,390 How on earth would you know? So it looks a bit like a prejudice, the same kind of prejudice that when Einstein famously said God doesn't play dice. 52 00:06:13,390 --> 00:06:18,550 In other words, in Einstein's view, everything in the world is physically determined. 53 00:06:18,550 --> 00:06:22,660 He was just voicing a prejudice. He didn't have a good reason for saying that. 54 00:06:22,660 --> 00:06:30,610 Of course, the progress of science can lead us to think that everything will be explained in due course in terms of physical laws. 55 00:06:30,610 --> 00:06:36,310 But the idea that we're anywhere near close to doing that is just fantasy. 56 00:06:36,310 --> 00:06:40,430 So I don't actually think that objection is nearly as strong. 57 00:06:40,430 --> 00:06:51,770 The causal closure principle seems really to to voice more and ambition or an aim of science rather than anything that we've discovered. 58 00:06:51,770 --> 00:07:00,080 But even if we do deny the principle, certainly mind body interaction seems peculiar, 59 00:07:00,080 --> 00:07:04,640 more significantly, I think it's hard to see how an immaterial mind could have evolved. 60 00:07:04,640 --> 00:07:14,510 I think objections from the theory theory of evolution are far more worrisome for the duellist. 61 00:07:14,510 --> 00:07:22,050 Do animals have minds? At what point in the sequence of evolution do minds appear? 62 00:07:22,050 --> 00:07:25,820 Or do you have to say that minds are not all or nothing? 63 00:07:25,820 --> 00:07:34,820 If you're going to allow a mind to evolve as a separate substance, does it mean you've got to have separate substance right there at the start? 64 00:07:34,820 --> 00:07:44,330 Amoebae and so on. Microbe's. OK, so we move away from dualism, where are we left? 65 00:07:44,330 --> 00:07:53,980 What can we have? Well, interaction ISM tells us, but mind and body interact in the pretty common sense way. 66 00:07:53,980 --> 00:08:00,770 Mind can causally influence the body. Body can causally influence the mind epiphenomenal ism. 67 00:08:00,770 --> 00:08:06,620 Some people are driven to that by trying to make sense of all this. They say that the mind is just an epiphenomenon. 68 00:08:06,620 --> 00:08:13,090 It doesn't actually have any causal effect on the body. It's just a sort of irrelevant spin off. 69 00:08:13,090 --> 00:08:17,660 The body works away. It does its stuff. The mind floats above it, as it were. 70 00:08:17,660 --> 00:08:25,280 We feel these things. We think these things. But actually, everything is determined by the body. 71 00:08:25,280 --> 00:08:30,260 Physicalism, the theory that all there is is physical stuff. 72 00:08:30,260 --> 00:08:38,000 There's nothing to the mind beyond the physical brain. It's important to know these terms like epiphenomenal ism. 73 00:08:38,000 --> 00:08:51,710 You find them bandied around a lot in the literature. Another view is property dualism, and this can be combined with some of those others. 74 00:08:51,710 --> 00:08:57,800 And there's a famous argument for this known as the knowledge argument of Frank Jackson. 75 00:08:57,800 --> 00:09:05,050 Imagine a scientist, let's call a Mary who learns all the physical facts about colour and colour perception, 76 00:09:05,050 --> 00:09:09,500 but who for some reason cannot see colour. Certainly got rods in her eyes. 77 00:09:09,500 --> 00:09:15,080 No cones or something like that. So no colour perception at all. 78 00:09:15,080 --> 00:09:20,870 But rather peculiarly has it has devoted her life to investigating colour. 79 00:09:20,870 --> 00:09:32,960 She knows all the facts there are about colour. Then wonderfully, she's given normal sight by whatever means some new operation. 80 00:09:32,960 --> 00:09:39,750 And suddenly she can actually see colour as well. She learns what colours look like. 81 00:09:39,750 --> 00:09:45,710 And it looks, doesn't it, as though she has learnt something new, something she did not know before. 82 00:09:45,710 --> 00:09:54,170 She now knows how colours look. So it's tempting to say from this sort of argument. 83 00:09:54,170 --> 00:10:00,650 But since she knew all the physical facts before she'd studied colour science, she knew all the physical stuff. 84 00:10:00,650 --> 00:10:07,310 The new thing that she learns how colours look. That must be something non-physical. 85 00:10:07,310 --> 00:10:15,380 So this can seem like an argument that forces you maybe not into substance dualism, not into saying that mind and body are distinct substances, 86 00:10:15,380 --> 00:10:24,020 but at any rate, to saying that they're quite distinct properties, physical properties, mental properties. 87 00:10:24,020 --> 00:10:28,730 But hang on a minute. What do we mean? You don't have the sheet, by the way. 88 00:10:28,730 --> 00:10:35,480 You'll be getting these next six slot slides next time with the ones on knowledge. 89 00:10:35,480 --> 00:10:42,230 What do we mean by physical stuff? What do we mean by physical properties? 90 00:10:42,230 --> 00:10:48,590 This is actually a really big problem these days back in the 17th and 18th centuries. 91 00:10:48,590 --> 00:10:57,860 Everybody knew what a physical cause was. You know, physical stuff is just extended inert stuff like billiard balls or stones. 92 00:10:57,860 --> 00:11:04,790 It just bashes into each other, does whatever it does, brute physical matter. 93 00:11:04,790 --> 00:11:10,700 But nowadays, our quantum scientists don't have brute physical matter like that. 94 00:11:10,700 --> 00:11:19,730 They've got exotic stuff with all sorts of weird properties, charge, spin, charm, strangeness. 95 00:11:19,730 --> 00:11:29,330 The further they deep they dig into the deep properties of the physical world, the weirder it becomes. 96 00:11:29,330 --> 00:11:38,570 So what do we mean when we talk about a physical property? We don't mean assuredly what they meant in the 17th, the 19th centuries. 97 00:11:38,570 --> 00:11:48,260 So let's suppose that our scientists came up with an explanation of consciousness that implied that even my new 98 00:11:48,260 --> 00:11:55,610 parts of matter have some kind of proto consciousness from which our consciousness came through evolution. 99 00:11:55,610 --> 00:12:01,130 Would that then make consciousness a physical property? Very weird. 100 00:12:01,130 --> 00:12:04,010 Very strange to speculate like this. 101 00:12:04,010 --> 00:12:11,660 But the point is to highlight that we don't actually have nearly as clear a concept of what a physical property is as we might wish. 102 00:12:11,660 --> 00:12:16,040 Sure, physicalist don't like that kind of thing. It seems spooky and it won't matter. 103 00:12:16,040 --> 00:12:20,870 Have these kind of ghost like consciousness. Sure. But maybe that's just the prejudice. 104 00:12:20,870 --> 00:12:29,160 Maybe in 100 years time, the science that comes out will seem as weird to people now as quantum mechanics does now. 105 00:12:29,160 --> 00:12:41,760 Two people a couple of hundred years ago. Now, without pursuing those sorts of spooky lines of enquiry. 106 00:12:41,760 --> 00:12:47,310 It's also worth bearing in mind that we need to get much clearer on what we mean by 107 00:12:47,310 --> 00:12:53,820 explanation and to be aware that you can have more than one kind of explanation. 108 00:12:53,820 --> 00:13:00,900 Here's an example. Suppose I type in 11 times 12 equals on my calculator and it comes out with one hundred and thirty two. 109 00:13:00,900 --> 00:13:06,960 Why? Why does it do that? Well, it's purely a physical object, right? 110 00:13:06,960 --> 00:13:13,440 My calculator is not thinking. But if I want to explain why it does what it does, why it shows one hundred and thirty two. 111 00:13:13,440 --> 00:13:17,790 Actually, the explanation is not a physical explanation. 112 00:13:17,790 --> 00:13:24,660 You can give a physical explanation for why my calculator faithfully reproduces mathematical facts. 113 00:13:24,660 --> 00:13:31,470 But the explanation as to why it comes up with that particular answer is a mathematical explanation, not a physical one. 114 00:13:31,470 --> 00:13:34,470 Likewise, if you're playing a chess computer. 115 00:13:34,470 --> 00:13:41,550 The reason why it moves its knight to Bishop three or whatever might be because that's the only move to guard against Checkmate. 116 00:13:41,550 --> 00:13:50,770 The illuminating explanation of why it behaves as it does is not given in physical terms, even if it's a physical object. 117 00:13:50,770 --> 00:13:58,190 Now, it's rather tempting to see the relation between brain and mind as analogous to that between hardware and software. 118 00:13:58,190 --> 00:14:04,200 Think about that chess computer and think about the fact that our explanation of our 119 00:14:04,200 --> 00:14:10,950 behaviour in mental terms is bound to be very different from a physical explanation. 120 00:14:10,950 --> 00:14:20,820 That being so, just like the chess computer, there may be no need to hypothesise some spooky substance, some immaterial substance. 121 00:14:20,820 --> 00:14:30,480 It might be simply that the way our bodies are put together is such that the best explanation of how we behave is to be given in intentional terms, 122 00:14:30,480 --> 00:14:38,740 not in physical terms. As I say, in the case of the computer, there's nothing weird or strange about it. 123 00:14:38,740 --> 00:14:47,590 Now, if the mind is something like the software of the body, something like a bodily process, 124 00:14:47,590 --> 00:14:58,220 rather than a separate substance, that does make it distinct from the mind, but not a distinct stuff. 125 00:14:58,220 --> 00:15:05,660 And this brings us to a very famous contribution of Gilbert Ryle. 126 00:15:05,660 --> 00:15:12,740 He imagines a visitor to Oxford who says, I've seen all these colleges, all these offices. 127 00:15:12,740 --> 00:15:16,100 Where's the university? 128 00:15:16,100 --> 00:15:22,380 And that's because they're going wrong, because they think the university is something separate from all the colleges and offices. 129 00:15:22,380 --> 00:15:28,830 It isn't. Now, maybe the same thing is going on when people talk about minds. 130 00:15:28,830 --> 00:15:33,390 They see the body. They see the bodies behaviour and then say, yes, where's the mind? 131 00:15:33,390 --> 00:15:45,020 Maybe the mind just is having a body that behaves in an appropriate way. 132 00:15:45,020 --> 00:15:52,760 Many minds problem, I've put that slide in just because you will come across it in the reading that you do on this topic. 133 00:15:52,760 --> 00:15:58,760 Another strange consequence of thinking of the mind as a separate substance from the body is that it 134 00:15:58,760 --> 00:16:09,460 raises the apparently absurd worry that you might have more than one mind associated with the same body. 135 00:16:09,460 --> 00:16:16,430 But I want to end by mentioning the hard problem as it is known now, 136 00:16:16,430 --> 00:16:24,650 suppose you accept what I've been saying about how the arguments for a separate substance don't seem to be very good, 137 00:16:24,650 --> 00:16:29,270 seem to be all sorts of problems with thinking of mind as a separate substance. 138 00:16:29,270 --> 00:16:32,780 On the other hand, when we think of the behaviour of computers, 139 00:16:32,780 --> 00:16:39,380 we can see that we have to draw a distinction between the physical object and the explanation of its behaviour. 140 00:16:39,380 --> 00:16:47,960 We can see that the explanation of how an object behaves might need to be put in non-physical terms in order to be illuminating. 141 00:16:47,960 --> 00:16:53,180 And the same clearly applies to us. We have evolved as purposive animals. 142 00:16:53,180 --> 00:17:00,020 The way we behave is often best explained in terms of those purposes, not directly in physical terms. 143 00:17:00,020 --> 00:17:07,490 But still, there's a problem, isn't there? Suppose I look at that light. 144 00:17:07,490 --> 00:17:11,240 I'm aware of it. Something is going on there. 145 00:17:11,240 --> 00:17:19,730 I feel that everything physical could be going on in my head just as it is now with all the same causal laws. 146 00:17:19,730 --> 00:17:26,270 And yet it not to be accompanied by that awareness that I have of that light. 147 00:17:26,270 --> 00:17:32,660 The phenomenal quality of it where I hit myself on the desk here and I feel a bit of pain. 148 00:17:32,660 --> 00:17:38,330 Why can't the physical things go on exactly as they are without that feel? 149 00:17:38,330 --> 00:17:45,770 And that, I think, remains the core of the problem of mind and body consciousness. 150 00:17:45,770 --> 00:17:52,970 We feel that we are directly aware of something substantial there, maybe not in the sense of a separate substance, 151 00:17:52,970 --> 00:17:57,950 but a real phenomenon that is not just a matter of physical behaviour. 152 00:17:57,950 --> 00:18:08,390 And I think that feeling, whether justified or not, lies behind the continuing puzzlement that philosophers do feel about this problem. 153 00:18:08,390 --> 00:18:16,370 I've sketched some of the approaches to that, some of the ways in which Cartesian dualism certainly doesn't seem to be an adequate solution to it. 154 00:18:16,370 --> 00:18:20,990 But this is definitely a problem that is going to run and run for some time yet. 155 00:18:20,990 --> 00:18:26,922 Thank you.