 Rhaid i ni'n adnolio am y gwybod i'ch eu gwaithau'n gweithio'n gwneud? Diolch yn gobeithio aruddwyd, ac ychwanegu'n gymhwyng ychydigodd dros ar gweithio'n gweithio'n gopadau ac rhaid i ni'n ffryd i'r ffordd hynny? Roedd ein ffordd ffordd hynny yn rhoi'r thysg hynny oherwydd gweithio ar draws i wychau fel gweithio ardeg, nad oedd yn chi yn gweithio'r gweithio'r wlad. I'm looking for natural explanations and the subject matter of philosophy and this is one of the things that's so wonderful about philosophy is everything. I mean as a philosophy you're not constrained to looking at one part of the world. There's a philosophy of physics, there's a philosophy of psychology, there's a philosophy of religion, there's a philosophy of mathematics, there's a philosophy of absolutely everything. That's because absolutely every subject is a subject that requires concepts that must be applied. So for example, if you're a scientist, then you'll look for causes. So the causal relation is extremely important to you. But a scientist doesn't stop and say, well what is causation? That's the job of a philosopher. Mae'r ffordd wedi oedd – yn ymddangos, dyma y byddai, yn cael ei rhan o'r armennig, rydyn ni'n cael ei rhan i ddweithio ar gyfer yr effeith? Ond yna ni'n bobl beth yw yma, e'ch gwrs yn gweithio ag ysgrifennu, e'ch gwrs yn gweithio argron. Yn ni'r menthe gweithio, mae gwnaethau y gweithio ar gwahanol y gallAN, ond mae hynna amser dyna bod dyl Fanolol yn ni ffawr yn gweithio. Dyna gweithio ar y gweithio drws unrhywbeth eich ei ging返— aroed yn y cyffredin, ar y cyfredin, ac yn y cyfredin iawn cyfrifhau, yna gweithi gynhyrch. Yn ni, mae hi'n gweithio ar gyfer y gweithio ar gyfer y gweithio, I hon, wrth gwrs, cymryd pa'r rhan o gyfnod MMR tofodd fod yn meddwl i'r rhan o'r troi at ddiwedd o'r eu cyfeirio yn yr awtstlu. Ond mae'r amguedd iddyn nhw'n meddwl. Mae'r amguedd iddyn nhw'n meddwl iddyn nhw? Mae'r hyn yn mynd i ddiwedd ar gyfer y gallan hwn nhw? Ond mae'r amguedd iddyn nhw'n meddwl yn meddwl i'r amguedd iddyn nhw? Felly, y ffilosophynydd y gallwn yr oesurrwyndig iddyn nhw yn credu y maen nhw'r weld, y syniogol, y ffilosyffr yn credu y maen nhw'r oesurrwyndig ei bod yn gweld y maen nhw yn credu y maen nhw yw'r weld, Yn ymgyrch, mae'n gweithio i'r ffordd y gallwn i gael y cysylltau ar y cyfnod y ffordd. Yn ymgyrch, mae'n gweld ffilosofi oes. Ymgyrch, mae'n gweld ffilosofi oes. Yn ymgyrch, mae'n gweld ffilosofi oes. Felly, mae'n gweld ffilosofi oes. Mae dyna, a weithio y gall person i chi'n gweld ffilosoio oes, am 400 oes filoedd a mynd i chi'n gweld ffilosняu hyfer oes yn oed, this is a very common assumption these days that we assume that the mind and the brain are the same thing. The question of what they are is the same thing is a very important philosophical question to which the answer is always certainly no. Because if the mind is the same thing, if you think of a neural state that's a bit electrical activity in the brain a neural event, yr event mirrors it's a let's take a belief essential condition for a belief is this is but to have a content okay all beliefs are about something aren't they you don't have a belief that isn't about something what is property of about nice is it's a very important property okay a brain states could have a property of being about anything Unw. So, ffx, yw'n mynd? Michelle. I'm entertaining a thought about Michelle right now. Okay, and you are too because you're thinking it's the ladies sitting at the front, etc. Now, do you think that I could have that very thought if Michelle didn't exist? Could I have that, the thought that I'm having, if Michelle didn't exist? No. Okay. Ond efallai'r gyfan hyn yw. Mae hynd yw ddechrau hon ar y dyma, dwi? Dyma fynd i du bywiau yn gwneud. Mae'r gwelliedig dyma'n ddechrau sydd wedi cael effaith cyf...... Wyddech chi'n rhai mynd ei gweld. Yn ysaf, mae'r peth yn ysaf sydd wedi'i cychelfogol i'w bwnt â blantau a gwtaith ffocl. Ac mae'n fideoch hefyd, ei gweithio efallai. Ond mae'r gwelliedig byddwch chi'n gweithio? Udych chi'n gweithio? Llyfr addysg. No. My bwysig yn y ddweud y dyma yw'r byd yma yn y dechrau llyfr nid yw, rwy'n nhw. My rydyn nhw'n fawr ddim yn cael ei fawr i'r bwysig. Yr hwn yw'r bwysig yw'n ni'n cael ei fawr i'r bwysig. Rydyn nhw'n gallu bod yw'n gofod ar y cyfnodd ac yn cael eu bwysig yw'r bwysig. Ond ydy'r rhesysau sy'n gwybod i'r byd i'r ddau a'r ffordd o'r ddau sydd yn fawr, ond mae'n ddau'r ddau. Yn ddau'r ddau'r ddau, nes ffilosfyrd yn ddau. Yn ffilosfyrd, ac yn ddau, mae'r ddau'r ddau, ac mae'r ddau'r ddau'r ddau, yn ddau'r ddau, yn ddau'r ddau, mae'r ddau'r ddau sydd yn ddau'r ddau, yn ffilosfyrd, dyma? Merseydiadol ei amser. Eyna yn dda ay flynyddoedd dyma thriker i Emwy, a mae dechrau'r ddau sydd yn fawr. yn dych Llingwyr Rh would.ذ yma mae'r ddau syd wedi eu hyfforddiadol ei newinkr關係. So, y cwestiw y Mae'r lleihwyr iawn, dwi'n rhan o adrwm, dwi'n rhan o adrwm mae'r llyfr yn cael ystod mewn nifer y sylwedd. Mae'r llyfr yn cael y llyfr yn cael ei ddemelly. Yn amser hynny mae'n gwybod wedi'u hanfod o'r listol, ac yno Fyarnau i'n gwybod i'r listol, a fyddai hynny ddwn i'r listol a fyddai hynny diolch. Maent ymmell pethau mae'n muddd ystod i'r listol, mae hynny'n cydain bod ydych i'r hynwn o boblach, i'r fath, i'r mynd i'r hunain, i'r hunain a'r hynny'r hyfforddiadau cyfforddiadau rhywb sy'n fath. Ond y overlap cyflomii... Felly, y fathau llunio'n ddod yn mynd i ddod yn y llunio cyfforddiad yma ym ysgrifennig yw mewn. Ac mae'n ddod y hyfforddiad yma, wedi'u ddod y fathau llunio cyfforddiadau, mae'n ddod i'r fathau llunio cyfforddiadau, We have no more reason to think they exist." It's a bit fishy you might think, but think about a woodless. That would make it seem like they are under rocks. It likes the damp and it believes it's damp under rocks. That's why it intends to go for a rock. Every time you pick up a rock you will find wood lice. What do I do in my garden? Mae'r ddau'r hyffordd gwyl. Mae'r ddau-wpedigau fel arweithwrs. Mae'n ddamp ar mwyloedd. Mae'n ddamp ar mwyloedd yn olygu arwyr, mae'r ddamp arwyr yn cael ei mynd neu'r olig o'r hyffordd. Mae'r ddamp ar mwyloedd yn contradictor o'r mechau. Fe wnaeth mae'r ddamp oes teimlo, mae'r ddamp ar ymddangos o'r wwloedd yw'r wwloedd. Mae'r weddangos o'i ddamp. Mae'r rhaid i ddesi codi'r astud ..Great Britain, but it really doesn't matter. It's a behavioural mechanism that we share too. And once they fly into the light, they have a photo taxi, positive photo taxis, they fly towards the light. Once you know that that's why a woodlouse does what it does, we don't have to attribute beliefs and desires to the woodlouse. In fact it becomes pointless. We eliminate the idea of woodlouse beliefs and desires. There is no such thing as the woodlouse's mind. The woodlouse doesn't have a mind. We don't need to postulate a mind. We can explain all its behaviour without appealing to a mind. And the eliminateivists think we can explain all your behaviour without appeal to a mind as well. So isn't it odd though? Can we have reason to believe that we don't have beliefs? Actually we can. The eliminateivist argument is a very very good one. And you can't just reject it by saying it defeats itself because we have to believe that eliminateivism is true. We have to have reasons for believing it's true. If they're right that we can explain all human behaviour and of course what we explain human behaviour in terms of is brain states. So the eliminateivists will agree that brain states are not mental states. They agree that there is no identity but they think as it's brain states that explain our behaviour we can just reject mental states. We don't need them at all. So counter-intuitively you don't have beliefs or desires or intentions and you're not rational. Sorry to bring that news to you. So I'm just going through a couple of questions here. That's philosophy of mind, that's the sort of thing. Are animals rational? Are pianos rational? I mean maybe this piano thinks that it's at the centre of the universe and it likes being there so it's not going to move for anyone. That's why it's staying still in this awkward position. Okay that's philosophy of mind. Let's have a quick look at philosophy of language. Okay what is meaning? I mean isn't it interesting that all I'm doing is making noises and if I had a flipchart I could make squiggles on a board. And you would look at them and you're listening to me and you're understanding what I'm saying. You're grasping it, you're somehow grasping the content of what I'm saying. Is that pretty magical? And it is extraordinary isn't it? What is meaning? Why do my words have meaning? And we could say that it's something like, I mean there's such a thing as a natural meaning so smoke means fire. So you see smoke and smoke is causally related to fire and you think okay there's smoke, there'll be a fire somewhere because they're causally related. But meaning isn't like that. So I can say, what's your name sir? Zee. So Zee asks me, is so and so a good philosopher? And I say his handwriting is excellent. Now the words I've just uttered have not in your mind before, I don't think unless you've listened to me before, they're correlated with the meaning that they have in that context. But you all know what I've said don't you? You can all work out that meaning immediately and you don't work that out from the strict and literal meaning of the words that I used because the words that I used don't have the strict and literal meaning that I used them to convey. I'm not tied up in my own syntax there but. So what is meaning and how do words get meaning? And some people think that meaning comes from use. So we point to something, we point to blue. So we ostensibly define something by saying that's blue. Well when I point like that, what am I pointing to? I'm pointing to curtains, I could be pointing to folds of fabric, I could be pointing to fabric, I could be pointing to the colour. How do we manage to pick up from the information that we have as children when we're taught what exactly words mean when they're pointed out to us? So that's the sort of thing you look at in philosophy of language. The other one is reference, so z refers to him. Well how does it do that and how does a name latch onto a person? How does reference, and just in the same way as how meaning comes about, how does reference come about? This is the sort of thing that philosophers of language think about. Philosophy of science, I've talked about already causation, which is a key topic in the philosophy of science. But also such things as observation being theory laden. What do I mean by that? Well you may think that what a scientist does is they observe the world, so either by observation or perhaps by experiment. And then they take down what they see and then they use logic to build a theory on the basis of that observation. So science is involved in observation and logic. You get a theory and then you test the theory because the theory will predict certain observations and you test whether the predictions that you've derived from your theory are in fact true or not. And if they are then your theory is confirmed to a small extent and if they're not your theory is falsified. The trouble is that you can't make an observation that isn't informed by theory. So here, let's take red for example. What do you think the word red means? Would anyone like to have a go at telling me what the word red means? Well it's a colour, but we all know it's a colour because it's like the word red is a symbol that we've agreed upon to mean a certain thing. So because we want to put the same language. Okay, you're absolutely right, but what I'm asking is what is that meaning? Don't I have a flip chart somewhere? I did ask for one. Okay, so you think the meaning of the word red reflects light at 650 nanometres? Anyone have any other meaning of the word red? A social construct that has different meanings in a different context. Can you give me an example of two different meanings of red? Red dead. Yes, that's a good one. Yes, there's a correlation, isn't there, an association between Manchester United and between socialism and red. But that's not usually thought of as the meaning of red. But it has different symbolism in different cultures. So for example in the West it would be seen as an indicator of danger. In China it would be seen as a symbol of prosperity. And in India it's a symbol of marriage, isn't it? Yes, okay, but these are associations rather than meanings. Okay, let's take the meaning that you've given me, but red is that which reflects light at 650 nanometres. Okay, let's do a thought experiment about that. Now a thought experiment is what philosophers do and it's very comfortable because we don't have to leave our armchairs to do it. A scientist does an experiment in the laboratory. And the scientist is constrained in the design of that experiment by the laws of nature. Now a philosopher is also constrained in the thought experiment he or she conducts, but not by the laws of nature, rather by the laws of logic. But we're trying to do the same thing. We're saying okay, the idea is that A is B. Well, if I can design an experiment that pulls apart A and B so I get A without B or B without A, then I know that A and B are not the same thing. Okay, so it would work exactly the same way in the laboratory as it would in your mind. Okay, so let's imagine a cosmic ray of some kind. Cosmic rays are very useful to philosophers. What the cosmic ray does is it makes objects like, let's pretend your jacket is red. It's probably an orangey sort of colour, isn't it? But let's say it's red. Okay, so a cosmic ray hits and it makes things like that, reflects light instead of its 650 nanometres. It reflects light at 400 nanometres. Now usually that would mean that we start to see it as blue. But this is a very odd cosmic ray because what it does is it changes the wavelengths but it doesn't change our experience. So we continue to see the jacket look like that, but it reflects light at 400 nanometres. Okay, has the colour of that jacket changed or not? Put your hand up if you think not. It looks like that still. Has the colour changed? Put your hand right up so I can see you. Don't be half-hearted. Okay, so most of you think not. Okay, who thinks the colour of that jacket has changed? And who has put in their hand up twice that has not allowed? You can't have both. You can have neither because sitting on the fence is always a good thing to do. Those of you who put your hands up the second time are wrong. There's no way we would say that the colour of the jacket had changed. When all that had changed is the wavelength of the light reflected from the jacket. If the jacket looks like that, we would say that it's still red or orange or whatever it is. What we learn from that is that red isn't the wavelength or rather the meaning of red is not the wavelength of light. We know that the colour red is realised. There's that word again. I used it before when I was talking about the mind. We know that the colour red is realised by objects reflecting at light at 650 nanometres. But that's not the meaning of the word red because the meaning of the word red is far more closely linked to our experience of colours than the fact that colours reflect light at certain wavelengths. I'll come to you in a second. That gives us another hypothesis about the meaning of the word red. Is the meaning of the word red that experience I have when I look at... What's your name? Jillie's jacket. Jillie? I'm having a certain experience when I'm looking at Jillie's jacket and so are you. Is red that experience? Put up your hand if you think yes it is. OK, you're wrong as well. Shall I tell you why you're wrong? OK, this is why you're wrong. OK, when you're teaching a child the colour words. OK, so you say that's blue, that's red, that's da da da da. Eventually, having done that a bit, you point only to curtains. You're asking for trouble, aren't you? You also point to other things. You point to jackets and carpets and jumpers and chairs and other blue things. But eventually you'll start saying, is that blue? And you might point to something red and say, is that blue? And what you're hoping is that the child's going to say no. Now, you have no idea what the child sees. You don't know what the child's experience is like, do you? So how can you check that if the word red means that inaccessible private experience? So you have no idea what I see when I look at Jilly's jacket, do you? You probably assume that you're seeing what I see, but you have no idea whether that's true or not. And yet we managed to communicate by means of that word red. We think it has the same meaning for all of us. If you're teaching a child, you want that child to grasp the meaning that you grasp, but you'd never be able to check it, would you? If red means a private experience, a nonexperienced, this is essentially private. So we know that the meaning of the word red is neither the wholly objective wavelength that an object reflects light at. And we also know that it's not the wholly subjective experience that we have when we see a colour. So what does red mean, do you think? Do you want to have another go? It's not blue. It's certainly true that you haven't grasped the word red unless you've grasped that it's not blue. You've got to distinguish things. That's true. Have defined brain states, as you go on, that have to be the same for a different reason? OK, when you say defined brain states, do you mean that? What does he mean? He means experience, actually, doesn't he? Actually, the fact is we might all have a different experience when we look at red. It's hugely unlikely, but it is possible, it's logically possible. What red is, it's one of those concepts that actually you can't define without circularity. An object is red if it appears red to a normal human being under normal circumstances. So you can't define the word red without appealing to the appearance of red, but you also can't define it without appeal to objects. Of course, the reason that objects that are red appear red to all of us, instead of just one of us, is because it's not the private experience that matters. As Wittgenstein puts it, you have to have an experience when your mother is teaching you red, and that experience must be different from the experience you have when you look at blue, but actually it doesn't matter at all what that experience is as long as you have it and it's different. Wittgenstein said, it's not a something, but it's not a nothing either, your experience of red. So what we were doing there was conducting a thought experiment. We were putting things apart in logic to see whether we were right to identify them and we see that we weren't right to identify them. We've got to pull them apart. Now there's a question there, but there's a question there first. Can you speak up? No, no, it doesn't turn blue. It starts reflecting light at 400 nanometres instead of 600 nanometres. That doesn't mean it turns blue. That's what we're asking whether that does mean it's turned blue. Well, when I gave the actual definition of red, which is that an object is red, if it appears red to normal human beings under normal circumstances, the reference to a normal human being is absolutely vital. And so is the reference to normal circumstances because, of course, red objects do not appear red if they're under a strange light. So it's not required that a red object must always appear red. It only appears red to normal human beings under normal circumstances. And you and then we must move on. I'm sort of troubled by this. As a physicist, I'm not so interested in the object as in the light that comes from it. As a physicist, I know that red light has certain wavelengths. So it depended of the object, what you see coming into your eye as a certain wavelength. If you have a prism, it will split white light into a number of colours. You look at red, what you're seeing is a particular wavelength. But what you're telling me is the empirical story about what we have discovered redness to be. When an object appears red to a normal human being under normal circumstances, we have discovered, science has discovered, that that object is reflecting light at 600 nanometres. So that's something we've discovered about redness. I'm sorry, but the object, the light is reflected and deflected from the object. And that's what we see as redness, isn't it? Can I just say that there is a scientific experiment where the... I actually don't care. Can I stop you? But you project the two secret bars, which are the two discrete things. And you can see all the colours. Absolutely sure you can. You can see it even though you're looking at the other light. So you perceive it, so it's your argument. What we're looking at is not what the scientific story about redness is. So, ffyrdiwch, gwyllt gael atomic number 79. Does gold mean atomic number 79? No, it doesn't. Because you know… Did you know that it was atomic number 79? Okay, does that mean you didn't understand the meaning of gold before you came here? You think you did understand the meaning of gold. I understood my meaning of gold. Oh, oh! Is that your husband? Os rydw i gondol Ier digwydd oedd y gallwn gwirionedd. If you'd asked him whether it was gold... It was what it was, you're ahead of consensus. Oh, my Scottishman! Ha ha ha ha! Do you see what I mean? We communicate... I mean the meaning comes when we can communicate by means of words. We knew what gold was. When science discovered that the atomic number of gold is 79, what science discovered was something about gold. finished to and she didn't change the meaning of gold. It gave us an extra belief about what gold was and in exactly the same way we had the meaning of the word red before science came along and told us that redness was what happens when a light is reflected off an object at 615nm. I'm not interested in any way of physics, sorry, because we're going on to politics and I want to leave at a time for a couple of questions here, sorry you had a question didn't you? It's really simplistic. Good. But it just occurred, if we observe and indoctrinate the embryo, for example in time it's really... I think I prefer physics. How do we know that this is the trend? That's quite a bit more simplistic. Roed is not the truth, whatever is the case. True, I mean actually I'm quite happy to talk about true if you like because truth is a very interesting philosophical thing. Can I talk about it in a minute? I'm going to talk about truth on the next slide. I'm just going to say politics, philosophy of politics, what's political philosophy? What's justice? What's equality? What are the principles by which we should govern society? I mean should we... Let's look at the distribution of property. I mean one of the jobs that a government does is back up some distribution of property. It might be equality or it might... I mean in this country for example it's not equality exactly but equality is important because we have a redistributive society don't we? So you, what's your name? Patricia. Patricia, you go out to earn a living and 22% at the very least of everything you earn is taken away from you by the government. Well why is the government making you slave for that 22% of time? For nothing. How can you justify that? Well we justify it on the grounds that 22% goes to build hospitals, roads, schools etc. And we might ask well if you don't have children, I don't have children, why should I pay for schools? I'm a pretty healthy person, why should I pay for hospitals come to that? So there's a principle of justice behind the idea of how you decide to distribute wealth within a society. You might decide not to get involved at all, so whatever you earn you keep. So there's no income tax at all. Now you might think you might, you would like that society but think about a society in which there isn't any income tax charged. There's no taxation so there wouldn't be any state built hospitals, roads, schools etc. So that's just one issue in political philosophy. Religion of course, the big one, does God exist? What's he like? Is free will compatible with determinism? So we think that the actions we perform, or some of them at least, are freely chosen by us. But actually you might also think that they're causally determined. So the laws of physics being what they are, everything you do is a result of the laws of nature plus whatever the conditions were just before you did it in your brain apart from anywhere else. Well can an action be both causally determined and freely chosen? And if so how that looks like a logical problem doesn't it? A token action, so just one action lifting my arm up there, was that both causally determined and freely chosen by me? And if so how? Well a soft determinist would say yes because free will and determinism are compatible. A hard determinist would say no free will and determinism aren't compatible and you were determined. That's why I raised my arm. And a libertarian would say they aren't compatible but you freely chose to raise your arm. And so there are three different positions. And of course all of us want to be compatibilists. We all want to think that you're both free and determined. But actually then you've got the logical problem of whether a token action can be both free and determined. So that's philosophy of religion. Of course we haven't got free will though there isn't any morality either. Because an action is moral only if it's freely chosen. And if you're a kleptomaniac then you won't be put in prison for stealing. You might be put in hospital but you're not put in prison. And okay if any subject matter is peculiarly the province of philosophy. I've said the province of philosophy is everything. But these four are peculiarly the province of philosophy logic. I mean some of you might have listened to my podcasts. There are podcasts on the critical reasoning. I look at what is an argument. How can we analyse an argument? How do we evaluate an argument and so on? So logic is the methodology used by philosophy. Now it's used by scientists too. It's used by human beings all the time. You are here today because of a little argument that went... OUDC said it was going to have an open day. I'd quite like to go to the open day. Therefore I'll go there now. Well that sort of practical reasoning is what brought you here. So argument is what human beings do all the time. To be rational is to argue. And what a philosopher does is stand back and look at what arguments are, what counts as a good argument, why it counts as a good argument and so on. Ethics. I notice that these two have something in common. What they have in common is that they're both normative. So physicists or any sort of scientist is concerned with the way the world is. It conducts experiments to look at the way the world is or the way the world could be under different situations. What it's not interested in is the way the world should be. That's the province of philosophy. So you should argue in a certain way. If your arguments are bad they shouldn't be. And we all understand that. If you derive from a set of premises a conclusion that actually doesn't follow from that conclusion, there's something normatively wrong with that argument, isn't there? You have argued badly. So bad and good come into it. Right and wrong come into it. Should and shouldn't come into it. And exactly the same thing happens here with ethics. So just as there are norms about their standards in accordance with which you should argue, in exactly the same way there are standards in accordance with which you should behave. And you can leave your knife any way you like, but not in my chest. And that's because it's wrong to do that. So a philosopher would say, well what does it mean to say something's wrong? What is it for an action to be wrong? What is it for an action to be right? Which actions are right? Which actions are wrong? And of course in the public sphere that becomes political philosophy. This ethics writ large is politics. Metaphysics. When you're doing metaphysics, what you're looking at is your ontology, your list of what exists. And you're also asking what its nature is. So okay, we looked at to do mental states exist and the eliminativists think not. The rest of us think yes. But once you think that mental states exist, you've got to say well what are they? What distinguishes a mental state from a physical state? We know that physical things occupy space. I mean there may be things in the very small sphere that occupy space in a rather odd way. But certainly all macro objects are three dimensional. Well are mental states three dimension? Of course they are if they're brain states. But we've already looked at whether they're brain states. Maybe they're not. In which case maybe minds are not inside the head. They're not located in space in the way physical objects are. And if I can't think about Michelle without Michelle existing, it looks as if my belief about Michelle is a relation between me and Michelle rather than something that's located in my head. Doesn't it? So that's metaphysics, an epistemology. Well okay I'm talking about how we can know things about what's true and what's not. Well how can I justify claim to know that something's true or not? I mean you all think that you're sitting watching a lecture in the lecture theatre in OUDCE but you might in a minute wake up and find you've still got that bloody lecture to go to tonight. You wish you hadn't signed on now. So you have reason to think that you're watching a lecture. Of course you do. Everything's with you as if you're sitting watching a lecture. But you know as well as I do that you could wake up any minute and you're up home in bed. So the reason you have for thinking you're in a lecture is not conclusive. Can you have conclusive reasons for anything? And if you can't, then can you know anything? What is knowledge anyway? Knowledge involves truth. You can't know something false and before you will shout at me you can believe that you know something false but your belief is false. So you can think you know that the earth is flat and there was a time when lots of people believed they knew the earth was flat but their belief that the earth was flat was false and therefore their belief that they knew the earth was flat was also false because a belief that's false cannot be knowledge. And if you do it in epistemology you know that. So this was built as philosophy in 45 minutes and I think that's 45 minutes. I hope I've convinced you that philosophy is the best subject in the world and if you want to do any more there's all these things that you can do including my podcasts which are completely free and available and I tunes you. Thank you for listening.