 OK, hi guys. Let's see. Hello. Good afternoon, class. Good afternoon. OK. So we had a couple of glitches with B-spec, but B-spec should be working fine now. And the PowerPoints for last time and for this time are all on B-spec. And each week, the PowerPoints will go on to B-spec. Getting a little bit of feedback. How's that? OK, so there are five parts to the class. What we're doing right now is we're looking at some of the foundational ideas in philosophy of mind, particularly dualism, behaviorism, and central state materialism. Central state materialism being the idea that the mind and the brain are identical. These are really basic ideas. Then we'll go on to functionalism, which is basically how most people think about the mind today. It is science's way of thinking about the brain and the mind. So it needs a lot of attention. And then we're going to go on to one of the key problems for functionalism, which is what kind of analysis it can give of consciousness is because problems about consciousness seem so intractable that the question of explaining where consciousness fits into the universe nowadays is, I guess, in anybody's list of the top 10 outstanding scientific problems is really not very easy to see how to address that. Then we'll look at the mind over time, the identity of the self, the relation between you and the person that was around 10 years ago or the person that will be around in 10 years. One makes it the same self over time. And then finally, we'll look at some general issues about the nature of psychological explanation. Get that reasonably clear as to the kind of structure we have. And so today, we're looking in foundations, we're doing dualism, and we're looking at Descartes' classic pieces from the meditations. And on Thursday, we'll go on to some kinds of behaviorism and the section from Ryle called Descartes' Smith in the Chalmers collection. So that's nine pages long, the Ryle selection. Can I just check, how many of you looked at the Descartes? Can you put your hand up if you look to the Descartes? OK, if you haven't done it, then please get onto it. Can you put your hand up if you looked at the Descartes and found it difficult? Aha. OK, so not quite everyone who looked at the Descartes found it difficult, but pretty much everyone. So I just say that to reassure you that this is perfectly normal. And the pattern you want to get into is do the reading, come to lecture. Then after the lecture, you do the reading again. And then after you've done the reading, you go to section, you discuss it. And after section, can you guess what you do next? Do the reading. So you just keep doing the reading. Each of these things, you need to read many times. And you need to discuss many times. OK, but when you get it, you will see that what these guys are doing is they are actually putting things in a straightforward way as you can. It is just that many of the ideas are quite difficult and often quite new. And quite hard to believe that they're saying that sometimes. OK, so there are three arguments in Descartes for dualism, dualism being the idea that there are two different kinds of stuff, mental stuff, and physical stuff. One argument that we looked at last time is that knowledge of your own existence is more certain than knowledge of any material thing could be. The second argument that we'll start out looking at today is that your conception of the self, your understanding of your own mind, isn't the understanding of a body. You could perfectly well conceive of yourself without a body. So body and self must be separate if you can think of one independently of thinking of the other. And the last argument is the hardest to get. It's that matter is divisible. Matter can always be cut in two, matter has parts. But the self doesn't seem to be divisible. The self doesn't seem to be made of components in the way that matter is. So you can think of it like this. We've got a firm conception of physical stuff. We know that physical stuff is made of atoms. Their atoms are all stacked together to make matter. And Descartes got these three arguments to say that whatever the mind is, it can't be physical. So he's saying there's got to be some other stuff. He doesn't call it ectoplasm, but some other kind of stuff that the mind is made of. Now the thing is that today I actually think most people would agree that most people working in the area would agree that these arguments of Descartes are extremely powerful. There's still the dominant arguments in philosophy of mind today. The thing is that Descartes' understanding of what would be implied wasn't really radical enough. He was right in thinking that these arguments are very powerful in showing that the mind doesn't seem to be anything physical. But where he went wrong was in having too easy a solution. He thought, well, there's an easy way out here. You just assume there's some non-physical stuff. That's what the mind is made of. That's what solves it all. But actually, these arguments work for ectoplasm too. Your knowledge of your own existence seems to be more certain than your knowledge of ectoplasm. I mean, whatever ectoplasm is, I mean, nobody. This is not some technical term I'm introducing here. Nobody has the slightest idea what this stuff might be. I mean, that's part of the problem. Sorry. Gold dust, yes, exactly. To give it a technical term, let's call it gold dust. But whatever it could be, whatever kind of stuff you postulate this to be, it's just as hard to see how the mind could be made of that. I mean, your knowledge of your own existence seems to be more certain than your knowledge of gold and dust or your knowledge of ectoplasm. It could all be a dream. The stuff about ectoplasm could all be a dream. You still know about your own mind. You can conceive of yourself without thinking about ectoplasm. Well, the last one is a bit harder. The self is indivisible. It's a bit hard to know whether ectoplasm is divisible. But I mean, since we have no idea what it is at all, it's hard to say. But these arguments are, actually, is this thing blocking off view of the screen? Yeah, would it be good if I moved this? OK, there we are. OK, does someone have a question? Yes? Yes? That's right. Well, your body's made up of cells. You yourself, when you look inside at your mind, yeah, the mind isn't made up of cells. That's the idea. We will spend quite a bit of time in this argument. It's not that I mean to be rushing on past them. We're going to go right back over and spend quite a bit in each of these moves. You mean this one about put in terms of ectoplasm? Yeah, I think it is. But the thing is, Descartes says, when Descartes's putting in terms of material things, the way you just put it is perfectly correct. You know of your own existence in a way that's more certain than your knowledge of any material thing could be. Right? But then Descartes says, so you know about, so you yourself must be non-physical. You yourself must be made of ectoplasm. And now we don't know what ectoplasm is, but whatever kind of stuff it is, suppose you manage to specify what ectoplasm is. Your knowledge of your own existence is still going to be more certain than your knowledge of ectoplasm. You see what I mean? I mean, if you think of it as being gold and dust, or you think of it as being some kind of gooey, sticky stuff that is observed during seaxes, or whatever you think it is, your knowledge that you exist will still be more certain by Descartes' lights than your knowledge of the existence of the ectoplasm. Once you specify what it is, yeah? Okay, we're going to keep going backwards and forwards over these arguments. I just want to suggest this is a general way of thinking about Descartes' arguments. You don't have to buy this, but this is a general way of thinking about what's valuable about them and what's not valuable. Okay, so these three arguments, let's kick off by looking at the second one. We looked at the first one last time, and at the end today, I'll come back to that first argument. You can conceive of yourself without a body, so the body and the self must be separate. I think in a way that's really pretty common sensical, that Descartes puts it like this, the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct since they're capable of being separated. So I hope what I'm about to say is not entirely autobiographical. I mean, I hope it's not just me, but here's the kind of thing I sometimes think of going to sleep. This is my funeral. There I am being carried aloft by friends, students, colleagues, and you know what they all have in common? They're all sorry. So I imagine this scene from a disembodied vantage point. I'm there watching them all saying, we wish we'd treated him right. We should have appreciated him while he was here. Boy, I'd do anything to have him back for just a moment. There they all are. But where am I in all this? Well, I'm not really bodied anymore, right? I mean, there is the husk there that is all these pigs have and serve them right. So I can imagine coming apart from my body. I can imagine having the out-of-body experience where I'm looking down, but that just shows that I can conceive of myself independently of my body. I mean, the way Descartes puts it is, the material world could be an entirely an illusion. It could be that all of your life, all you've been getting are hallucinations. Some people do spend a lot of their lives having hallucinations. It could be that that's all you've ever got. So you wouldn't have any knowledge of a body at all. You and your mental states would still exist. So your knowledge of your own mental states can't be the same thing as your knowledge of material bodies. Or to put it around the other way, people sometimes suppose that you could have a body just, somebody could have a body just like yours without being conscious. I mean, this is the popular idea of a zombie. As you can see, zombies look just like you. And yet the thing is, although a zombie can move and act just like you, is not conscious. That's the scary thing about zombies, yeah? So actually, this is a kind of unflattering portrait. I mean, really, the zombie could look just like you physically. The zombie could be molecule for molecule identical to you physically, but still not be conscious. So here's how Descartes puts it. I might consider the body of a man as a kind of machine equipped with and made up of bones, nerves, muscles, veins, blood, and skin in such a way that even if there were no mind in it, it would still perform all the same movements as it does now in those cases where movement is not under control of the will or consequently of the mind. So you can conceive of mind and body independently of one another. So if you think of how you know of your own mind, you know about your own mind by introspection, by thinking about what you get in meditation or what you get by an imaginative understanding of other people, you can find out about your own mind in ways that they don't have anything to do with your knowledge of your brain. You could have a profound knowledge of your own mind without knowing that you have a brain at all, right? I mean, presumably people have, for centuries, managed that where they didn't know that the brain was particularly relevant to the mind. And on the other hand, you could make a complete study of the brain without realizing that the thing that had the brain had a mind. I mean, suppose you have Martian psychologists who look at us. I mean, we study bees without knowing whether bees are conscious. Are bees conscious? Class? Yeah. Right, well, that's actually my hunch too, but I had a colleague, zoologist friend who actually did work on bees full time. That was his job. And he was very clear that bees were not conscious. I never, I mean, they were too small. Right? How can something that small be conscious? Aha! The key thing is, the key thing is when you're studying, yeah, uh-huh, well, yeah, there may be something to that. Yes, so it shouldn't matter. Yeah, yeah. Sorry, I thought there was a question back there. Yeah. You can't just say I refute and leave it at that. I hear my refute you. Yeah. I hear my refute you too. That's really the key thing I want, yeah. If you take another example, the sea slug, the sea slug brain is now completely understood. I mean, it's an astonishing thing that all the connections between the neurons and the sea slug brain have been mapped. There is a completely comprehensive understanding of the sea slug brain. Are sea slugs conscious? I mean, nobody knows, right? How do you figure it? How do you really get a definitive test on that one? So Martians could do that to us. Martians could come and study us and say, look at these little charts. It's absolutely marvelous. They make these cars, they run about the planet in these little cars. They have all these buildings. Look at what they get up to. We have mapped their brains. We know such a lot about their brains. Let me show you over here. We have mapped our brain and we know the computationally exactly what their brains do. But Martians split into two camps. Some of them say, well, I think they are conscious. Others say, no, they're so small and they're so kind of fleshy. Nothing that kind of fleshy and small could possibly be conscious. It doesn't really make sense. It doesn't really matter. They could understand the brain completely. So you could have a comprehensive understanding of the brain without even knowing whether a mind was there. You could have a comprehensive understanding of the mind without having grasped that there is a brain or that a brain's even relevant. So brain and mind just must be distinct. They've got to be two different things. That's Descartes' second argument for saying that the mind can't be physical. Fair enough? How do we know that we're conscious? Yes, the cats know that they're conscious. We're taking it as a working assumption that cats are conscious, right? Yeah. But do they know they're conscious? Yeah. They're part of stuff, yeah. I don't know. It seems to me that knowing that you're conscious is a really different thing to being conscious. Knowing that you're conscious requires you have some concept of consciousness. You can think about consciousness. It's a little bit fancy to be able to think that you're conscious. I guess my impulse would be to think that cats are conscious, all right, but they can't think about that stuff. You know, they can't be connoisseurs of their own conscious states, yeah? Should we? Should we? Can't. Don't we? You can say, I love the way that makes me feel, right? You think about your own conscious states the whole time. If you like pain, for example, you might say, oh, this pain is exquisite, yeah? Whereas a cat can't do that. I mean, I'm not boasting here, but, yeah? Yeah. Okay, one, two. I think they're the way that psychologists study the brain. They're always thinking about how does this connect to the conscious mind. But I don't know that it actually makes much difference to the way the science is done, because when you think about the way people study the honeybees or the way people study sea slugs, they really don't spend a lot of time torturing over whether these things are conscious. I mean, if they did, it might be harder to do the experiments, yeah? But they really don't think about that. And the thing is that the same methodology that's used for studying relatively simple animals is the same methodology that scientists use in studying the human brain. It's not as if when you get to the human brain, oh, everything amps up and everything changes so far as a physiological study goes. The physiological study looks exactly the same. I mean, how could it be different? You're just looking at yourselves and how they're connected and the chemistry and so on. Yeah, yeah? Yeah, yeah. What yours is what the difference is? Yeah, that's fair enough. Well, this goes back to something someone said last time about thinking in sensation. I mean, thinking is something that you very often do in language, right? So thinking is something kind of fancy. Like just having a sensation, any kind of animal can do that. You stick a pin in a snail. It's gonna feel a sensation, presumably, I think. But does that mean that the snail is thinking? Doing that kind of thing that we do with language? Just having the sensation is one thing. Just curling up into a ball because of that pin going in. That's one thing, but thinking about it, that's what I think is different. It would have to be more than reactionary. It would have to be something that was disconnected from the here and now, so you could reflect on the event and reflect on what made it happen, what was gonna make it happen again, how to avoid it in the future and so on. It might involve planning. So if you think of thinking as being, in the first instance, something verbal, you see what it means, something you do with language, then sensation doesn't require language. Okay, things are hotting up and I really want to hear what people say, but I will try to be brief or one, two, three, and then there's something else up here, okay, yeah. Thank you, yeah, yeah. The mirror tests would, so if something can recognize itself in a mirror, then it's self aware, yeah. So they actually did this a little while ago at my son's daycare, they did the same test they do with animals, they put red dots in everybody's forehead and then let them see themselves in the mirror to see if they rubbed them off and apparently the, I'm sorry to say the animals are a great deal better than the UC two-year-olds, but there you go. Sorry, but that's what you mean by a test for self-awareness. Yes. Okay, intelligent use of a mirror. That's what we're talking about is, yeah, fair enough, yes. Okay, so that's different to self-awareness, to self-consciousness. I think that is self-awareness. Right. Oh, that's a very interesting distinction, yeah, that's very good, okay, okay. So intelligent use of a mirror just shows only that you have the conception of yourself as having a body, yeah. But self-consciousness would require what I was talking about a moment ago, knowing that you have experiences and so on. Yes, okay, I just buy that completely, that's a very good point, yeah. Next, yeah. We are assuming that humans are questionless, yeah. How did humans think before language? Yeah, the thing I say about language is, there's a complex question about the relation between thought and language, yeah. You might think that thinking comes first and makes language possible. That's kind of what your question suggests, yeah. I don't want to disagree with that really. Even if thinking comes first and makes language possible, it's still what we're doing in using language. Using language is an intelligent activity. It involves thought, yeah. That's really all I meant. I'm just to get straight into the distinction between thinking and sensation. Do you see what I mean? Yeah, I don't understand how I got the question. That's right. Yeah. I think that's right. I think, yeah, so having backed off a little bit, let me say that for most kinds of thinking, language, it just seems perfectly obvious that language is needed. And if you think about, can a dog know that its master will be home three weeks from today? Can a dog think the earth existed for a long time before I did? Well, when you look at your dog and you think, I wonder what they're thinking. You know pretty well they're not thinking that, right? They're not thinking about dinosaurs or something. They're not thinking about, am I really a descendant of a dinosaur? No, that can't be right. You see what I mean? So many thoughts are just not available to you if you don't have language. Next? Yes. That's right. I was thinking of the snail sensation as the same thing as consciousness, yeah. Yes. Would they feel the sensation at all? That's what I was thinking, they don't feel the sensation. Yeah. Okay. We will come back to this. I don't mean to ride over things here. These are all complex questions that you guys are raising. So I'm trying to say something about them, but I don't want to suggest that's the end of the story in any of these things. Yeah. We are going to come back to the B. I'm going to prolong it. We shouldn't move on, but let's say it quickly and I won't say anything. Infants. Yeah, well, with very young children, I guess the general trajectory of so much work has been that initially people thought that not much was going on with children until they were three or four or five, yeah. But there's been such a flood of work in the last few decades showing what complex things infants are capable of. That you'd have to be pretty tough-minded to say that even newborn infants aren't capable of thought. Yeah, I don't want either to deny that. Yeah, I mean, the point is they don't have language. Yeah. When you say he puts them at the same level, I mean, so far as respect and so on go. Yeah, I don't quite agree with that, actually, if it's the infant or the starving lion. I know what I go for, if you see what I mean. I know whose side I'm on. And that may be speciesists, but what the hell, yeah. So, but just purely cognitively, infants are pretty unusual. Yeah, that's not to say that animals, there isn't a lot of intelligence in some animals. Yeah, yeah. Yes. We're really talking about how to think of the mind or the soul, yeah. That there is some something, your knowledge of your own mental states, but actually at the end today, in this section, your knowledge of your own existence, what I want to do is push a bit further on that idea of knowledge of a soul or mind. Yes, so we'll look at that a bit more today. That's something Descartes completely for granted, but it's really a baffling idea once you start to brood on it. Okay, okay. So let's look at these three arguments. We looked at this one last week, we just looked at that one. So let's look at this one about divisibility. I just want to say something quite brief about this because it's hard to get what he's after here and we're going to spend more time on this in a couple of weeks. Matter is divisible, but the self is indivisible. Descartes says, body is by its very nature always divisible. You take a knife, you can always cut a bit of mustard in half, you can always cut it in half again. The mind is utterly indivisible. Another way of putting it is, here's another way he puts it, when I consider the mind, that is to say myself, in as much as I am only a thinking thing, I cannot distinguish in myself any parts, but apprehend myself to be clearly one and entire. The body has limbs, the physical body has organs, the body has all these constituents that are assembled and all these constituents can exist on their own, but the mind doesn't seem to have parts in that way. If you think of, suppose you have any two experiences, you have an experience of intense intellectual stimulation and at the same time, you feel that something has just run over your foot, then you are having these two experiences, but they themselves seem to be part of some broader thing. What it's like to have your current mental life, they're part of some more global conscious state that you're having right now. So one way you could think of it is, what you've got right now is really just one big experience. Anything, any other experience, any descriptions you have of particular experiences like a pain or a sensation are just aspects of that single experience you're having right now. And the mental life has a kind of seamlessness about it in the way that everything is connected to everything else. And the physical stuff, the body is just not like that. Another way to put it is in terms of what you're aware of, that's to say, if you're aware of one thing over here and aware of another thing over there, if you're aware of the projector there and you're aware of the board there, then you're aware of both of those things. That's to say, you can compare them. You can say, are they close together? Is one bigger than the other? Did one last longer than the other? Or these two things that you're aware of at the same time, they might be forming a pattern. There's a single perspective from which you're getting everything right now. You are kind of like the vanishing point of that perspective from which you're getting everything right now. And you can be aware of all these things as related to each other or forming a pattern. If you said, well, with one part of my mind, I'm aware of A, with another part of my mind, I'm aware of B, but I can't compare A and B because it's different bits of my mind that are aware of the two of them. I can't put these two things together and say, is one bigger than the other? Is one lasting longer than the other? Are they close? Because it's just different bits of my mind that are in question here. That makes no sense. How could that be? You see what I mean? If you're aware of this thing here and that thing there, how could you be in a position to say, but I don't know whether they're close or I can make sense of the question whether they're close? Of course you can because there's a single act of consciousness in which you're encompassing both of them. But with the brain, it makes perfect sense to say, with one bit of my brain, I'm responding to A, with another bit of my brain, I'm responding to B, but those two bits of brain aren't connected to each other so I can't compare A and B because they're different bits of brain that are in question. That makes perfect sense. I mean, that happens. Your brain could be responding to two different things without putting them together. Whereas your mind doesn't have components like that, your mind doesn't have different channels in that sense of channels that are independent of one another. Your mind just packs everything together into what the world is like from a single perspective. So the mind has a kind of unity that you can't explain in biological terms. That's what Descartes thinking, yep. Couldn't the aid in the superego be considered as parts of the mind? That is a very good example. That is the kind of splitting of the mind that Descartes is saying is impossible. Yep, when you say I've got an aid in the superego, was that your example, aid in superego, when you say? These are just operating, these are just playing different games. Yeah, the aid in the superego. The thing is, I think what Descartes has to say back here is if you really take this talk very seriously about the aid in the superego, what you're talking about here are really two different individuals that are communicating or they are conflicting or they may just be ignoring one another and going about their business separately. But the more seriously you take this talk about the aid in the superego, the more it looks like you have two different individuals here just because they are two different perspectives from which the world is being viewed. You see what I mean? The really difficult thing with understanding what's going on with the talk about the aid in the superego is to understand in what sense they are parts of a single mind. Another way to think of it is, suppose I'm trying to imagine what life is like for you. Suppose I'm saying, I mean, suppose I'm saying, why is he doing this stuff? And the analyst says, well, here's what he's doing and here's what a superego is doing. But what I really want to get is, what's it like in your shoes? How does the world seem to you? How does that feel to be like that? Well, I don't want to be in a position where I can say, well, I can get what a superego is thinking. That's one way of imagining what the world is like in his shoes. I can get what his aid is thinking. That's another way of imagining what the world is like in his shoes. But have I put that together? I have no idea. You see what I mean? Whereas if you say, well, I want to get his total perspective in the world, that's the thing when it seems like there's got to be some kind of unity. So I think Descartes has to play back there. That basic question about the aid and the superego, are we really to think of them as separate individuals or are this really, in some sense, just one mind here? In that case, how can you make sense of this? Talk about conflict or not connecting? Yes. Isn't that equally divisible? Yeah, you could talk about the Apple Corporation as a structure and saying it is all these bits. There's a search and design and there's marketing and so on. But nonetheless, there's a whole thing here too. Yeah, that's the idea. I think the key point here is that the kind of unity, it's just that I was about to, I'm just working myself back to the thing that says in the slide there, that when you're explaining what the unity of the mind comes to, the unity of a corporation is not the same thing as the unity of a collection of bits. If you want to understand the organization of a corporation, you can't really understand that in terms, say, of atomic physics or in terms of just how individual people are going about their business. You need to have some global picture of how the whole organism works and explain how these things are plugging into it. Whereas with the brain, you really can bust it down atomically and look at it cell by cell and then look at how the cells are all wired together. The mind doesn't seem to have that kind of atomic structure where you can look at all the bits and pieces individually and then say, and now here's how you make a mind. You stack together all these sensations and thoughts and feelings and motivations. Whereas you can do that with a brain. You can say you take the cells and you stick them together this way. Yeah, so a mind can be, the brain can be bust down into its atomic ingredients. Whereas the mind doesn't really make sense to do that. There are these different aspects to it, but that's not the same thing as to say, you can take those aspects and then put them together and that's how you make a mind. Something like that, I think, is what Descartes is thinking. Yeah, yep, aha, that really is. You're talking about that broadly, that transversely running broadband of fibers known as the corpus callosum. Yeah, that we're actually going to spend an entire session on in just a couple of weeks. So I strongly agree with the importance of that. You guys are just going a bit too fast. Could you all just slow down a bit please? No, that's great. That's exactly a case as we'll come to where you've got a patient, it seems to me an example where you've got a mind that's been fragmented. There's some sense in which you're getting a shattering of the mind here. Yeah, so that really is a case in which you've got a mind that seems to have lost some kind of unity. If you haven't come across this before, this will be a bit cryptic, but we'll actually spend a lot of time on this. If you want to read ahead on this, you might look at the article by Nagel called Brain, Bisexuality and the Unity of Consciousness, which if only you'd come to this class a couple of years ago, you could have written the article, but there you go. That is actually about the implications of these procedures for what Descartes is saying. Yeah. Yes. Well, the way you described it, that's two different parts of the mind. Yeah. If you're remembering your teacher from a couple of years ago, and you're thinking, boy, he was much better than Campbell, that's a purely mental exercise, right? You're putting those together as, I mean, the whole point is you can't do the comparison. Yeah. Yeah. Yeah. Yes, yes, yes, going on. People use memory in a lot of different ways. I mean, if you lift a heavy weight, yeah, it can sometimes be a little bit easier to lift another heavy weight a moment later. Your muscle kind of got used to that heavy weight. And people say, well, your muscle is remembering what it just did. Yeah. That's not memory. That's a perfectly good sense of memory. Yeah. Or your phone remembers who you rang last. I mean, you just do ring last number, right? There is a broad sense of memory in which you could perfectly well be something physical. But usually when we're talking about memory in this class anyway, or I think in ordinary life when we're talking about memory, usually we're talking about something mental. When you talk about looking at the face of someone you know well in an awesome evening and remembering those summers long ago, yeah. That's mental, yeah. Yeah, okay. Memory is a kind of elastic term. Okay, so that's Descartes' second two arguments. I want to go back now and look again at the argument we were working through last time, this thing about knowledge of your own existence. Descartes says, that proposition, I am, I exist. That's necessarily true whenever it's put forward by me or conceived by my mind. Every time you think that, you've got to be right when you think you exist. So the certainty with which you know of your own existence is greater than the certainty with which you could know of the existence of any physical thing. Even if an evil demon is manipulating all your experiences, manipulating all your thoughts, if I'm supposing that, okay, bye-bye, if I'm supposing that there's some supremely powerful and if it's permissible to say malicious deceiver who's deliberately trying to trick me in every way he can, what can I say about what characteristics I have? Can I say I have even the most insignificant of characteristics that belong to body? Well, no, of course you can't, right? That was a main point last time. If you're in that situation, you think maybe this is all a dream, maybe this is all hallucinations, then you don't know of any of your physical characteristics. And Descartes says at last I've discovered it, thought that alone is inseparable from me. So the thing that you know exists is something thinking. So let's just pause in the structure here. Here's what's going on. Descartes does some thinking. It might be right, it might be wrong, but he's doing some thinking. And then he moves from that to I am thinking. And then he moves from that to so I exist. This is Descartes' Kajito. This is supposed to be the foundation of all philosophy according to Descartes. That's where you start. You get a particular conscious thinking. So you look inside your mind, there is a particular thinking, and you move from that to I'm thinking, and you move from that to I exist. Please don't anticipate everything I'm about to say, but yes, all right. Yes, yes, I wouldn't have thought so. I mean, I would agree that you can sleep without dreaming or thinking. In fact, some of us can just look out the window and not think at all, right? It's a gift, there's just nothing going on. Oh, I'm sorry to say, but the thing about that case is that there is not that you're reflecting I am thinking and getting it wrong. The minute you snap to and say I'm thinking, well, you must be right, that's his idea. In your case where you're having a dreamless sleep, you're not going through this rigmarole, yeah? So it's not as if you're going through this rigmarole and getting it wrong. The minute you're alert enough to be going through this stuff, you must be right in everything you're thinking. That's what he's saying. Yes? Yeah, that's a really excellent question. Thought is inseparable from me, yeah? So dreamless sleep should be impossible. Yeah, that's your point, yeah? Yeah, I guess that, yeah. Yeah, I actually think that's pretty devastating. I mean, there are things you can say to that. You can say, well, the self is something that's capable of thinking, but isn't actually doing it right now. That's all that's going on. But really, what is it then if it's not thinking? When all we know about this hectoplasm is that it has this capacity for thought? You see what I mean? I think that's a really powerful remark. Austin Jackson, do you want to comment on that? I mean, actually, my inquireration is to say take out just has to fold. I think that's a very powerful remark. But maybe I'm missing something. Yeah, okay, one, two, three, four, five. Okay, right, okay, I'll try to be quick, yeah. Lucid dreaming, yeah. Yeah, that one, isn't that one a bit more like the, well, there's an easy reply to this and then there's a bit where it gets harder, yeah? There's a bit where you say, well, in lucid dreaming, I guess you're thinking, yeah? So this bit, the thinking is caught, but who is it that's doing the thinking is a harder question because it depends how lucid your dream is. I mean, I don't know much about this, but my impression is that in lucid dreaming, there's a lot of range of possibilities. But one possibility is you don't know who you are anymore except that you're, I don't know, the monkey with the umbrella or whatever it might be in this particular case. You see what I mean? So that might attack the bit. I don't know who this is, yeah, but you still know about the thinking. Is that your idea? Yes. I think Descartes' line in this, and this might be a mistake, but Descartes' line in this is that you can't have fake thoughts. If it seems to you like you're having a whole bunch of thoughts in your lucid dream, then you are thinking. You can't be wrong about whether you're thinking. I mean, just seeming to you that you're having a whole bunch of thoughts, that itself is a kind of thinking. That's the picture, so that there can't be an error there. Okay, yeah, I can't remember what the other was, but I think you were next, yeah. Yes, that's right. Yeah, I mean, what happens when you wake up is very puzzling. I mean, I don't know what there is. You know, you wake up and you know that all that stuff happened last night, and you know it was you, and this dismal realization crashes in on you. Well, I don't know. I don't mean to be too autobiographical here, but that happens and you just take it for granted, it was the same thing the whole way through, yeah. You don't get away with saying, but that wasn't the real me or something. Yeah, that wasn't me. But that's what happens, but the question is, and they can't really make any sense of it when you're saying that thinking isn't separable from me. If thinking isn't separable from me, then how can I have continued through a gap in my existence? You see what I mean? Something else, right. But that's the thing, if you say it's something else that's steering, not the thinking, we don't have any idea yet what that is, and how could you have certain knowledge of the existence of that thing? I'm sorry, the person, you want to come in on this, yeah. It's not still thinking if you're aware of it. It is still thinking. That's right. Okay, yeah, the awareness itself is thinking. No argument about that. I think the point that these guys are making, going back to, yeah, your initial point, was what you're aware of is there's something existing without thinking? You see what I mean? And how can that be? How could there have been something there that was you but wasn't thinking if thought isn't separable from me? Yeah, that's a challenge. Okay, well, yeah. I mean, these questions are all extremely important questions. It's not like, this is random stuff, I'm just dismissing. These are all comments that are as important as anything I'm saying, yeah. That's right. I mean, that's how we take it, that if I just look out the window and everything goes blank for a bit, then you don't say, well, I cease to exist, then, yeah. I mean, yeah. Sorry, carry on. Yeah, look, let me give an example here. Suppose you say that, okay, Descartes is saying thought is inseparable from the self, right? That's what Descartes is saying. And the reason he says this is when you've got this argument, I get from the fact of my thinking to my certainty that I exist. Well, how could that be if there was any more to you than just thinking? You see what I mean? There can't be any more to you than just thinking. And there can't even be a physical body. So an analogy might be, suppose you take the notion of a beam of light. I hope I can, okay, I hope I don't just shut all the power down or something. Okay, a beam of light, okay. Now, this is a simple demonstration. Here is a beam of light, right? Coming from, let's say, that panel there. You got a beam of light. Now, a beam of light, what a beam of light does is it shines, right? Yes? So just as the self thinks a beam of light shines, okay? Now here is a gap in the beam of light, okay? A period which is not shining. And now there you go. Now it's shiny again. So here is the puzzle. Was the beam of light there for that period in which there wasn't any shining? No, of course not. I mean, is there a beam of, is there a beam of light there now, class? No, right. Why not? Because there isn't any shining, right? So if Descartes is saying, think of thinking as the shining of the self, if you see what I mean. And there is no more to the self than shining. Then how can the self continue through a gap when there's no shining or rather no thinking? You see what I mean? How could that be? That is the puzzle. I've lost track of who's in line. Okay. Okay, carry on, yeah. Yeah, your thoughts might be going on anyhow, yeah. That would be another reply Descartes might make. I really was thinking even though it didn't seem like it, yeah. Yes, you could be thinking without realizing that you're thinking, yeah. That could happen. You're making, you find that you're making a labyrinth plan to kill the next little neighbor's cat. And then you suddenly come to, you're absolutely shocked at what you've been thinking. You see what I mean? You can get absorbed in a train of thought but not realize that you're, that's what you mean about reading. It's not that when you're reading your thinking, oh my God, I can't believe I'm finally reading War and Peace. You see what I mean? You can do that. You can just sit there thinking, oh my God, I'm reading War and Peace finally. But usually you don't do that. You just read the stuff and you don't think about it. Is that your point? Yes. Well, the question is what is this thing that exists? Is not something physical? Yeah, that's what he thinks is established. So if it's not, if it was something physical and you can make perfect sense of the idea that the biological brain and body continue through a gap in the thinking. But if all you've got on this thing is that it's thinks, then what is there to continue in existence? It's kind of like the beam of light. I mean, there's no more to a beam of light than the shining. If there's no more to the self than the thinking, how could the self continue? That's the challenge. But I agree with both those points, though, that Descartes might say, no, there really was thinking going on. You just didn't realize it. That's a good point in a movie might make. Yeah. Yes. The same thing goes for plants. It's like, isn't a plant existing that doesn't think it's like, well, you're not a plant, so it doesn't really matter. That could just be a projection in your eyes. Right, is that what Descartes's getting at? Um, he's got to reject the plant an example. Yeah, because the plant is just a physical thing. The thing about the metrics seems to be much more serious because, I mean, what Descartes is pushing here is really an early version of the metrics. Yeah, I mean, that's what it is. I mean, that's, I mean, well, I don't want to get out of my depth here. The Descartes, I think I understand. The metrics, I have never really grasped. But, um, I, it's something like that. Like, if you take away the genius and put in some chip or something, and something like that is what's going on in the metrics, yeah. And actually, um, there is the same question. If you're really in that scenario, then what kind of knowledge can you have if you're on existence? I actually want to press that a bit further. Let me try pressing this a bit further and then come back in just a couple of minutes. Yeah, if I've got or haven't got it, what you're saying. So here's Descartes' line of thought. You get a particular conscious thinking. You move from that to I am thinking, and you move from that to I exist. This is really worth pausing over, because it really matters this line of thought for how you think of the self. If this line of thought is okay, then the self really does seem to be something non-physical. How could you have certain knowledge of its existence if you're in a matrix scenario and it doesn't exist, and it's not physical? Well, it's got to be something non-physical. That's what it seems like. If you know of your own existence simply on the basis of knowledge of your thoughts, then there can't really be anything more to you than your thoughts, right? That's all that we've got here. The trouble is, there's a basic point here that Hume said this long ago, that you can check this out now. Look inside your own mind right now. Don't concentrate in your surroundings for just a second. Just cut sideways, look inside your own mind, and see what's there. What is there in your own mind right now? Actually, psychologists do do experiments in this world. You're given a tape recorder to carry with you, and a random point during the day, a buzzer goes off saying, just note what you're thinking about right now, where you are and what you're thinking about right now, and then the researchers put together what they call the Thought Activity Correlation. So if you're doing something dangerous, you're going to be thinking about exactly what you're doing. You see what I mean? Whereas if you're just going for a walk, then you're not going to be thinking about the walk the whole time. You're going to be thinking about your plans for later in the week. So you just record the Thought Activity Correlation. The Thought Activity Correlation is very, very low in lectures. I'm sorry to say that when people get that random buzz and say what they're thinking, it's usually got not much to do with a lecture. But anyway, be that as it may. Focus right now on what's in your mind. Hume said, when you look inside your mind, do you find the self? Do you find the soul? Hume says, no. When I enter most intimately into what I call myself, I always stumble on some particular perception or other of heat or cold, light or shade, love or hatred, pain or pleasure. So you might be brooding about your enemies or friends or whatever it is. But you never get anything but some particular thought, some particular perception, some particular sensation. What you never get when you look inside your own mind is something you'd call the self. If when you looked inside your own mind, you really got the self, that would have to be something that was always there, something that was invariably the same through the whole course of your lives. Because that's what the self is, right? I mean, yourself is something that's kind of always around. So when you looked inside your own mind, it would be like having tinnitus or something. You just got this, this can sing, oh, that's me, right? There you are. You could look inside your own mind. Hi. That's yourself. And there it is again. And Hume's point is, when you think about what that is actually saying, that's absurd. Nothing like that happens. What's really going on is, when you look inside your mind, all you ever encounter are particular thoughts. And when you say I, when you talk about the self, there is nothing that you get any knowledge of by just looking inside your own mind. Talk about me, the thing that's having the thoughts. Talk about this self. It's really like a theoretical postulate. It's as if you're talking about something you've discovered in the laboratory and you say, well, something must be causing that. Let's call that magnetism or let's call that an electron. You postulate something. So you look inside your own mind. You see all those thoughts. You encounter all those sensations and you say something is having those thoughts. Something is having those sensations. I'm going to give it a name. I'll call it me. That's me that's having all those thoughts. You see what I mean? You just postulated this thing. Just as if you've got a series of murders, say, you might postulate some one person committed all those murders. You never actually encountered that person, but you just postulate a single hand is at work in all these killings. Similarly, when you get all your thoughts, you say a single thing is having all those thoughts. I bet that's me. I bet that's me again. Yeah, yeah. Well, when you figure it out, come back, yeah? Yes. Yes. Yes. Yes. Yeah, that really matters. That thing about some thoughts you want to say, that's not really me that was thinking that. Yeah, that was a demon. That was my demons. Yeah, right. They were making me think that. Yeah, I think that's a very important notion, that notion of the thoughts I endorse, the thoughts that are the authentic me, something like that. It can also be a dodge. If I spend most of my life thinking about that cat, and then whenever I am unmasked, I say, but that's not the authentic me. That can be pretty implausible, or it can be a dodge to do that. But seriously, it really matters which of your thinking you really get behind, and you say, I completely go along with that, that's right. But the thing is, there seems to be a more basic notion of what's running through your mind. What's something that happens is your mind rather than somebody else's. And some of the stuff that runs through your mind, you get behind, and you say that's mine, and some of it you don't. But it's all running through your mind. And that's really what we're talking about here, that kind of more primitive notion of it's running through your mind rather than the mind of someone else in the class, for example. Yeah. Yes, it is constantly changing. I thought, can you do that louder? Yes. Yeah, that connects actually to the last question. There's how the self is presented, something like that, and that can vary a lot. And there are decisions you make as to what I'm going to present as the real me, what is the authentic self. I think that's right. But there's got to be some conception of what it is that makes it the same person, the same self over all this time. I mean, it's good that you emphasize the possibility of difference, but it's one thing to be killed and replaced by another. I mean, it's one thing for me to go through a lot of changes and then come back next week and barely recognizable. It's a different situation if someone else replaces me. You see what I mean? And you've got to be able to say, what's the difference there? What is making it the same thing all the way through? Yeah, that's something we wouldn't spend a lot of time on, actually. That is the problem of personal identity. Okay, but come back to that. Okay, last one. Well, there are mental changes too. I mean, I could really go through a revolution. I could convert to some, yeah, I could convert to, I'm sorry, I could convert to something. I could convert to something and that might make very radical changes to my psychology. I no longer like the people I used to like, I no longer like the food I used to like. My psychology might change. Let me carry on a little bit because I think that is the key question. What is the self, what conception do you have of it? I mean, the thing I'm saying here is on Descartes' picture, really all that's going on is, you encounter a particular bit of thinking, you look inside your mind, you encounter a particular bit of thinking, and you say, oh, so I'm doing that thinking, I exist. But what is that? You don't have any idea what that is. I mean, it seems to me, your knowledge of your own existence comes from right outside just looking inside your own mind. Your knowledge of your own existence comes from knowing which thing you are as a physical thing, how other people connect to you, for example. I'll skip over the remarks of the Silver Surfer. Well, I will just quote the Silver Surfer. When all is said and done, who is the dreamer and which is the dream? And the insight there that has always struck me is, these two questions are connected. You don't know who the dreamer is until you know which the dream is. You've got to know something about your own existence as a real, concrete object before you can draw any conclusions about who the dreamer is. So you've got, first of all, to know which of your perceptions are real. If you really didn't know about your own existence, then all you could say is, there's some thinking going on. That was a comment Lichtenberg made about Descartes. You don't have that right to say, I exist. If you really think all this is maybe a dream, all you can say is, some thinking is going on. You know, it's as if Descartes' picture is you look inside your own mind, you get the hard crystalline self, the enduring thing that is always there through all these variations in your thoughts. But there is no such self. You look inside your own mind, all you're getting are particular thoughts. One way to think of it is like this. Suppose that what was going on is this. Suppose there is a soul. Well, one way to think of what's going on when you look inside your own mind is, you encounter all these particular thoughts. And then you say, something's having those thoughts. Let's call it me. But of course, you have no guarantee that there is any one thing that is thinking all those thoughts. Each of these thoughts might be being had by something different. It's kind of like the case of a serial killer. You say, look, all these killings happened where you think there is just one person at work. But really, it might be many different people. You don't know that. All you're getting is the killings, if you see what I mean. You're not getting who did it. So if you look inside your own mind and you've got a whole bunch of thoughts, all you're getting is each of those thoughts and you're postulating there's something that's doing that thinking, but it might be something different in each case. There's no reason to think there's an abiding me, a continuous self that is doing all that. I suppose that what was going on was that there was a whole string of souls underlying those thoughts that you have when you look inside your mind. You look inside your mind, you encounter all those particular stabs of pain, of joy, of longing, whatever you get when you look inside your own mind. But suppose that what's underlying it is a string of souls. Each of them might be connected to the next so that they transmit their momentum as are the underlying causes of your thoughts to the next one. But maybe there's thousands of souls there over a period of an hour, say maybe since you came into this room, each soul you have has lasted only a few hundred milliseconds and boom, then it's transmitted all its impulses to the next soul coming up, gone out of existence itself. But there's the same overlay of thoughts that they're generating. Everything would be just the same to you as it is now. All you get when you look inside your own mind is those particular thoughts. So you don't have knowledge of the existence of any one of those souls just from looking inside of your mind. You don't have knowledge of the existence of any soul at all. Another way to put it is to say, suppose that actually your body right now has associated with it a thousand different souls underlying the same set of thoughts. Everything would seem just the same. The hard fact that you encounter when you look inside your own mind, that's the thoughts. The thing that is doing the thinking, you don't encounter that at all when you look inside your own mind. There might be thousands of them. There might be none. It might be just the thoughts. Why not? Why think there's a self there at all underlying the thoughts? So when Descartes says, I'm thinking really, he should just be saying, there's thinking going on. You look inside your mind right now and you say, low, thinking, low, a sensation. That's all you have the right to. You have no idea what that I might be. If you think of yourself as a biological human being, then you know what you're talking about. Then you can say, this is the same biological human being that had these parents, that lived for so long, that has done all this stuff. But when Descartes says, the certainty with which you know of your own existence is greater than the certainty with which you could know of the existence of anything, that just seems to be a mistake. If you suppose that you don't have any knowledge of physical things at all, then you also don't have any knowledge of the self. All that's going on is you're encountering particular thoughts. You don't have any certain knowledge of the existence of any concrete thing. The self can't be a purely mental thing in the way that Descartes supposes. The self has got to be something biological. OK, here ends the lesson for today. Great questions. Thank you very much. Great discussion.