Knowledge & Scepticism (Peter Millican - General Philosophy)

so this week's topic is mainly knowledge with a little bit more to say to round off skepticism our four luminaries there we've got Freddy heir AJ heir who was professor at New College when I was an undergraduate Edmund Gettier famous for writing a three-page paper in the journal analysis in 1963 I'm not sure whether he's published anything since but it suffice to make him very famous then we've got Hilary Putnam who will come to at the very end and Tim Williamson on the right who is professor here a successor to aja ax Tim's work isn't actually going to feature in this lecture or indeed in the readings you have but he's one of the most prominent epistemologists in the world so it's as well to know that he's around if you find yourself giving up paper and you see him in the audience beware he's universally feared for the sharpness and precision of his questions okay so we've seen some skeptical arguments most famously those of Descartes and those sorts of arguments rather suggest that if we put a threshold for knowledge very high then we're quite likely to be driven to the conclusion that we don't know anything at all Descartes own answers don't seem to work very well other answers are all very controversial it's rather tempting to try to get round this problem by redefining the notion of knowledge to provide a useful distinction amongst the beliefs we have maybe none of them are only very very few like I exist will actually reach the highest threshold but surely it makes sense to try to define a more moderate more reasonable threshold because we do want to distinguish between things that we know in a perfect ordinary sense and things that we don't know so we naturally get the question what is knowledge how should we understand the notion of knowledge now questions of the form what is X feature quite prominently in philosophy if you go back to Plato and look in his dialogues you'll see that Socrates is always asking this sort of question in fact it used to be the case I think that people thought of this sort of thing is absolutely paradigm attak of what philosophers do philosophers search for essences by trying to define things I don't think you'll find it's nearly as prominent these days but such questions still come up quite a lot in topics like personal identity or freedom what do we mean by freedom what is freedom now such questions if you think about it a rather puzzling because they could just be asking when do we apply the word X where X is freedom knowledge or whatever but that sort of question seems to be just about our use of language that we want to go deeper than that to ask what is a genuine case of X if that question isn't just about our use of language then what is it it seems rather peculiar what could knowledge be other than what we refer to using the word knowledge so let me give you an example take the discipline of geography suppose that the study of geography started out as the study of places in terms of their location physical characteristics mineral resources the natural environment that sort of thing I'm not sure whether that was true but let's suppose that it was then over time people became interested in things like land use economic considerations maybe even culture and if you studied geography now you will find that culture is one of the things that get studied now you can imagine someone saying that's all very well you now study culture as part of geography but is culture really part of geography does geography really include cultural things well if the word geography is now used to cover cultural matters amongst others then sure the discipline of geography includes culture how could it not so it might well look as though the kinds of questions we're asking when we ask what is X what is knowledge just come down to language and in the 1950s and 60s Oxford philosophy was famously identified with ordinary language philosophy as though the purpose of philosophy was just getting clear about how we use ordinary language if that were all there is to it then it would be rather an uninteresting kind of question but with most of the concepts that interest philosophers there is something deeper at stake take the case of freedom which we'll be looking at in a week or two there we're not just interested in how we use the word freedom we want to know what kinds of Acts we should describe as free because the notion of freedom is tied to moral responsibility we think it matters whether somebody is free it could turn out that we describe actions as free when really from a God's eye point of view they're not maybe we describe people as free in certain circumstances in ordinary life but actually if we knew about it there's no moral responsibility there no genuine freedom so there is a deeper metaphysical question underlying the linguistic question now likewise in the case of knowledge the concept of knowledge has a normative aspect when we say something's knowledge we're not just categorizing it as something that is called knowledge we're saying that it's reliable that it has a certain Authority so it is possible to ask of a particular belief well everyone says they know this but is it really knowledge do they really know it again a similar issue arises with strawsons response to the problem of a problem of induction it's on your induction reading list he famously says that inductive methods just are what we mean by reasonable when we describe an inference about the world as reasonable that just means it meets inductive standards but a very well-known answer to strossen is to say hang on a minute now when we say that a method of inference is reasonable we're not just saying that this is the kind of inference that everybody calls reasonable we actually mean that it is reasonable that it has normative force that this kind of inference really does convey assurance to the conclusion the kind of conceptual analysis that we're doing on the concept of knowledge provides a nice example of this and it's that's a good reason for having it in this general philosophy course from this example you can get an idea of the kinds of things that typically pop up in these sorts of discussions so one of the things that often comes up is appeal to linguistic intuitions now when people talk about intuition it's sometimes a bit sloppy as though they're saying oh well this is just something I think an intuition you've got to accept it but actually linguistic intuitions have a particular authority because if you're a native expert speaker of your language that then certain things do just come naturally to you to say and that does carry some Authority for the standard use of language now obviously that doesn't necessarily tell you anything about philosophical truth but it does keep you on the rails of using language correctly puzzle cases also feature a lot as we'll see in this lecture some people call these intuition pumps the idea of a puzzle cases that you sketch out some hypothetical scenario and then you ask well what would you say about that and clearly what you try to do is devise puzzle cases which steer your hearers intuitions in the way you want to take them so often you'll find in philosophical debate each side is producing puzzle cases to favor their own particular point of view you'll find in personal identity for example puzzle cases feature quite highly then obviously we get argument and we get systematization we try to pull all these intuitions and thoughts together to make sense of them all together so let's now embark on a discussion of knowledge and its variants trying to employ some of these methods to straighten out what we want to say about it so first of all let's distinguish between three different kinds of knowledge acquaintances knowing how and knowing that what we're interested in here is propositional knowledge knowledge that P a strange phrase but you'll find philosophers use it quite a lot so P is a proposition could be any old proposition but notice knowing that P is the case is quite different from having acquaintance with somebody or something or having practical knowledge for example I know how to ride a bike I don't exactly know how I do it I'm ignorant of all sorts of propositions that would explain how I manage to remain upright on a bike but I have the practical knowledge that is I can actually do it that's irrelevant here we're talking about factual knowledge okay so how might we begin to pin down what we mean by knowledge that P what is it for somebody let's call them s the subject to know a proposition P well the standard traditional analysis is to say first of all P has to be true you can't know a proposition that's false you might think you know it but if actually it's false you don't know it secondly you have to believe it you can't be said to know something you don't even believe and thirdly you have to be justified in giving it so those are the three standard conditions sometimes called the JTB analysis justified true belief a Jair who is particularly well known in this connection gave the last two conditions slightly differently he said that to know something you have to be sure of it and you have to have the right to be sure and you might think that's rather preferable if I just vaguely believe something without any strong commitment that might not be enough for knowledge suppose something to my mind has a 60% probability oh I reckon it's going to rain tomorrow something like that and maybe it's justified because I've seen the weather forecast but is that knowledge probably we'd say it isn't that kind of weak belief isn't enough you've got to be sure in order for it to count as knowledge and you have to have the right to be sure at any rate that seems quite plausible but let's ask some further questions about all this if somebody knows that P does it actually follow that P must be true notice that there are two slightly different claims that might be made here when I say if S knows that P P must be true or if s knows that P P is necessarily true that's an ambiguous claim on the one hand I might be saying that if S knows that P it follows that P is necessarily true but P is a necessary truth but it might be tempting to think that but it's just wrong I know that I exist but that I exist is not a necessary truth it's not like one equals one or two is greater than one I could easily not have existed once I didn't some time I won't but I do know that I exist right now don't I so it's simply not true and it can't follow from the meaning of know that the only things you can know are necessary truths the second interpretation of this claim however looks much more plausible necessarily if S knows that P then P is true something can't count as a case of propositional knowledge unless the proposition in question is true and that seems right but do be ever so careful when you use words like necessarily in philosophy always be careful to watch for the scope of the modal operator so distinguish between the two versions there in the second case you see necessarily lies outside the brackets whereas in the first case if you were to put brackets necessarily lies inside so talking about the scope of the modal operator sounds terribly technical but be very aware that word orderings of this sort can matter a great deal in philosophy let's now ask is it in fact the case that if somebody knows some proposition that proposition must be true well supposing I say I know that France is hexagonal I know that France is hexagonal and Italy is shaped like a boot but of course France isn't hexagonal so there we are I know a falsehood now that seems to me to be just a confusion there is a sense in which France is hexagonal namely that it's roughly hexagonal in that sense I can know that France is hexagonal there's another sense of precise sense in which France isn't anything like hexagonal and in that sense I can't know that it is so as long as we're clear as what we mean but about what we mean by hexagonal exactly hexagonal or roughly hexagonal that straightens out the problem for a different case if you want to get your philosophy tutors really cross say something like this well that might be true for you but it's not true for me philosophers hate that often people say that kind of thing when all they really mean is I believe P but you don't believe P so some people will say it was true in the medieval period that the Sun orbited around the earth no it wasn't it wasn't true it was universally believed but it was never true probably it was quite a reasonable belief at that time that didn't make it true take another example it's true we think that the continents drift for centuries millennia nobody believed that but it was in fact true indeed if you didn't think it was true way back in the time of the dinosaurs and so on you're going to have a very difficult job explaining the distribution of fossils around the world that distribution only makes sense in the context that continents were moving even when nobody believed it so don't confuse P is true with everyone believes that P they're quite different let's move on I'm going to take it for granted from now on that you can't know a falsehood what about belief in order to know that P do you have to believe P this isn't so clear suppose for example I'm in a quiz and I'm asked let's say to compare a list of capital cities and the countries and I have to say which city is the capital city of each country and suppose I say I don't know I haven't a clue I don't know any of these and then somebody says go on have a go have a guess well I really don't know it's random go on guess and I do and I get them all right now there might be some very plausible explanation of that it might be that when I was at school I learnt all these things maybe I had a teacher who was really keen on capital cities and fortunately the test was confined to countries that existed when I was at school and although I've completely forgotten all those lessons I'm able to do the test accurately I didn't believe that I knew but actually I gave the right answers and you can imagine the quiz master saying afterwards Millikan didn't think he knew any of those but in fact he did know them now one way of dealing with this kind of problem is to say I had unconscious knowledge of the capital cities and in that same sense you might want to say I had unconscious belief we can flesh this out a bit and suppose somebody's putting one of those quizzes they claim to be guessing they make their guesses and all their guesses come out wrong but then you put them in the quiz again they guess again they come out wrong again but they come out wrong consistently they're still getting the same thing well clearly they don't know the answers because they're getting them wrong but you might want to say they've got a none kind of unconscious belief because they're consistently giving the same answers and that could give you a way of saying that knowledge does require belief even if you accept that in the case of the quiz I do have knowledge you could say yes you can have unconscious knowledge but only if you've got unconscious belief only if your answers display a kind of consistency the related case is the strange phenomenon called blind sight this is where someone has damage to their brain in such a way that they have no conscious awareness of seeing anything and yet if you ask them to point to things they can do it with reasonable reliability so if you take them into a room spin them around and say point to the desk they'll say I can't see a thing how do you expect me to point to the desk and you say go on yes and they guess and when they do guess they get it right much better than chance so again with this sort of case it might be tempting to say they know something even though they don't believe it here the idea of unconscious belief may seem a little bit less plausible because there's no long-term memory or consistent pattern underlying the behavior a related problem it's tempting to think that knowledge must be completely conscious that if you know something you must know that you know it so at one extreme you've got the question do you even need to believe it at the other extreme you've got people who might want to say that if you know it not only do you have to believe it you have to know that you know well that at least must be wrong suppose it's true that in order to know something I have to know that I know it in that case if I know that P I have to know that I know that P and that means I have to know that I know that I know that P which means that I have to know that I know that I know that I know that P and obviously there's no stop to that in order to know that P I have to know that I know that I know and so on even when there are Googleplex nose in that sentence something I'm obviously completely incapable of understanding let alone believing there's no way that you can possibly believe an infinite number of those propositions and I I personally lose grip on what's being said once you've got five or six nose in there so insisting on consciousness all the way through that all knowledge has to be self-reflective and known to be known is just not going to work okay I'm going to put the question of belief to one side now and move on to the key condition that attracts most of the attention because the main point in distinguishing between just having a belief that P and knowing that P seems to be to focus on justification the main reason we want a concept of knowledge is to distinguish between things that we really know and things that we think we know so let's just assume that P is true here what is it that makes the difference between truly believing that P and knowing that P suppose I have a true belief that P that alone surely isn't enough to imply that I know it it might be just a lucky guess it might be something I've been told by someone who's actually completely unreliable yet on this occasion they just happen to have told me a truth there are all sorts of ways that I can have a true belief and yet it fails to be knowledge because it's not justified so in areas terms if I'm to know that P I must have a right to believe it or a right to be sure of it at least that seems very plausible here the shadow of skepticism can come back to haunt us suppose I believe that P what is required for this to be knowledge well plausibly it has to be justified no doubt it will be justified in terms of other beliefs if you asked how do you know that P I'm likely to have to appeal to other beliefs call them Q and R and then the question can arise okay how can you justify Q and R and they recover require further justification perhaps in terms of s and T and so we go on it looks like there's a threat of infinite regress here everything has to be justified by reference to something else how can you stop it well there are two different approaches that are traditionally taken indeed it's difficult to see how else you could do it one of them is coherent ISM which simply says you have this web of interlocking beliefs and if they all cohere together strongly enough then they can justify each other the other approach foundationalism says that ultimately you hit rock bottom ultimately you get to certain things that you can just know directly without there having to be justified by anything else maybe one equals one for example how do you know one equals one well I just see it to be true I don't have to justify that in terms of anything else how do you know you're thinking well I just see it to be true like Descartes was a foundationalist he thought some beliefs were just totally secure in and of themselves a more modern approach to halting the regress of justification which moves away from the emphasis on conscious justification which we've seen is probably not something that we want to insist on right the way through it's called externalism externalism features in a lot of modern approaches to philosophy an internal ista counter justification is one that requires that all the relevant factors that play a role in assessing a belief as worthy of being called knowledge must be cognitively accept accessible to the subject nothing can be hidden an externalist doesn't require this an externalist by contrast will say that some factors that are relevant to judging whether you're justified in believing something may be inaccessible to you external to you now one obvious advantage of this is the following suppose you want to say that dogs can know things or cats can know things well that better not be in terms of some intellectual justification the dog or the cat is able to provide so how does the dog know that there's a cat nearby well it smells it can the dog give an explanation of that of course it can't what makes this knowledge is that there's a reliable causal connection between the smell and the existence of a cat nearby and the dogs detecting the smell and the smell actually being there so you've got a reliable causal link between the cat and the dog sensing the presence of a cat now it's quite tempting to say that the key to knowledge in this sort of case is not intellectual justification not reflection but simply the existence of that reliable causal link and the dogs having reliable faculties well why not say the same about us why not say that we are capable of knowing things without necessarily knowing how we know because we've already seen after all that we don't want to say that you can only know that P if you can know that you know that P why not go the whole hog and say you don't even have to be able to give an account of how you know that you're justified this brings us to the most famous puzzle cases in epistemology possibly the most famous puzzle cases in the whole of philosophy the Gettier cases are fantastically well known probably because they're so clear and decisive against the justified true belief analysis of knowledge or at least they seem to be so let's suppose that P is something that I'm justified in believing and let's suppose the P clearly implies Q there's no doubt whatever that P implies Q so I believe that P I have a justified belief that P we're assuming that and I then infer Q where Q obviously follows from P does it follow that I'm justified in believing q would you agree that's how it sounds very plausible if I'm justified in believing P and Q obviously follows from P surely I must be justified in believing Q that's how you get the Gettier cases so here's one example suppose I'm in the desert I see what is in fact a mirage I think and I'm justified in believing let us suppose that I'm seeing an oasis I infer that there's no races over there and so I turned to my companion and I point and I say there's an oasis over there now in fact there is an oasis over there but it's hidden behind a sand dune what I'm seeing is a mirage but coincidentally there is an oasis in that direction so I believe that there's no ASIS over there it's true that there's no ASIS over there I'm justified in believing that I see an oasis and I've inferred from the supposition I see an oasis - they're actually being an oasis over there it looks like I've got a justified true belief but we don't want to say it's a case of knowledge another example which i think is slightly more plausible case of the kind of example that Getty a himself gives is this suppose we have a load of applicants for a job just two of them are men one of the men is very well qualified one of the men is very poorly qualified all the rest are women and they're much much better qualified than the badly qualified man now suppose I have it on good authority that the well-qualified man is going to get the job so I believe that a man is going to get the job and I've got a justified belief that a man is going to get the job unbeknown to me however there's some funny business going on I don't know maybe involving the the Masons or bribery or blackmail or what-have-you and actually the other man gets the job in this situation I have a justified belief that a man would get the job it's true that a man did get the job but I certainly didn't know that a man would get the job because there's a kind of accident my justification led me to the belief that the well-qualified man would get the job but in fact that a man would get the job has turned out to be true by some quite different route now these sorts of cases do seem to refute refute the standard justified true belief account of knowledge so it's tempting to add a fourth condition maybe we should say that S knows that P if and only if P is true s believes that P and S is justified in believing that P in a way that doesn't depend on any falsehood that's a way of trying to evade the Gettier counter examples where somebody infers a truth from a falsehood and thus achieves a justified belief that isn't knowledge now back in the days when I was a student this sort of thing trying to patch up the traditional analysis of knowledge to avoid the Getty a counter-examples was quite a major industry lots of papers came out with people trying to invent conditions that would get around the counter examples it's a rather sad history because all this effort failed to produce any convincing resolution of the problem here's an example of the sort of problem we face suppose I'm organizing some event and I want to know how many people were there maybe the reason I want to know how many people were there is because I want to make a judgment as to which room to use for a future event of that kind so somebody comes to me and they say oh there were exactly 78 people there what interests me is whether there were more than 40 if there were more than 40 then I have to use a big room rather than a small room next time so they tell me there were exactly 78 people there I infer that there were more than 40 arguably I know that there were more than 40 but let's suppose the reporter actually got it wrong there weren't 78 there were 77 I'm still inclined to say I know that there are more than 40 so I've inferred a truth from a falsehood that hasn't undermined its claim to being knowledge now you might want to get around that you might want to say no what you did was infer that there were more than 40 people from the fact that he believes that there were 78 and you have the knowledge that people can go wrong in little ways but there's an implicit probability judgment there you're making the judgment that if somebody says there were 78 and says it sincerely they've got good faculties and that's the kind of thing it's overwhelmingly probable that there were more than 40 it's not overwhelmingly probable that there were exactly 78 so maybe that gets you out of it lets out a fifth condition but there's a general problem with heading in the direction of probabilities the so called lottery paradox it's very tempting to try to get round of these problems these kinds of problems by saying in order to have knowledge you've got to have a sufficiently high probability that's the key thing it's not whether you've inferred something from a falsehood it's having a sufficiently high probability of truth but suppose we've got a billion tickets in a lottery well I believe that the ticket with zeros in every place won't win indeed I'm pretty sure it it won't win there's only a one in a billion chance that it's going to win I believe that the next ticket after that won't win either in fact I believe apparently quite reasonably of every single ticket but it won't win nevertheless one of them will win and because of this we're reluctant to call my belief about any of these tickets knowledge so if I go and buy a ticket in a billion ticket lottery and then I say well I know it won't win I think you'd probably say no you don't know you've got a very probable belief an extremely probable belief that it won't win but you don't know that it won't win because there's a chance that it will even if that chance is tiny now if that's right then the lottery paradox involves real problems for any attempt to explain knowledge in terms of sufficiently high probabilities because however high the probability is you can make it a trillion ticket lottery or whatever you can always get a lottery in which your belief that this ticket won't win will have as high or higher a probability than any belief which isn't a hundred percent certain and yet we're not going to want to call it knowledge okay so maybe we want to say it's not exactly a matter of probability it's a matter of ruling out accidents what we don't want is to allow as knowledge a belief that accidentally happens to be true I thought I knew that one person was going to get the job and it's a kind of accident as far as far as my knowledge was concerned that somebody else got it that's what rules it out it's a kind of accident that there's an oasis over there in the same direction as the Mirage so forth actually it's extremely difficult to pin this down suppose I have a car whose speedometer gradually corrodes let's say that the particular time it just happens to be accurate enough to ensure that I'm complying with the law let's say I always drive at what I think is thirty eight miles an hour along a road with a speed limit of 40 miles an hour fortunately the corrosion of my speedometer is such that it just keeps me within plus or minus two miles of an and a an hour of the actual speed so I'm safe well is it an accident that I'm safe in a sense yes in a sense no given that the speedometer has corroded I'm very lucky that it's keeping me within that margin but given that it's keeping weet me within that margin it's no accident that I'm safe again if I occasionally hallucinate things does that mean it's just a matter of chance that my current belief isn't an elucidation it's very difficult to pin these things down in a way that will give us a satisfactory account of knowledge another problem is known as contextualism suppose you want to get a train up north and I say I know that the Train is scheduled to leave at seventeen thirty six it's a train I regularly take so I can assure you it's scheduled to leave at seventeen thirty six but maybe you've got a really important appointment and you're not content with my saying that so you say do you really know that it leaves then I absolutely need to make that appointment okay I say I'll check on the web and you can imagine this going even further I know you're familiar with the timetable and you've checked the web but do you really really know I really absolutely have to be there okay I'll ring up the station and you can imagine a sequence of checks each more stringent than the last which suggests that the threshold we require to count something as knowledge can be variable we put a higher and higher hurdle depending on the importance of the task and that suggests that maybe knowledge isn't an absolute category maybe it's dependent on our particular purposes let's also consider the context in which we use the word knowledge within ordinary life so consider this contrast does she know that her husband is cheating on her imagine that being said in a soap opera or something like that now that probably means something like does she believe he's cheating on her like we all do you could imagine it being said in a context where there's some uncertainty as to whether he's achieved maybe there's all sorts of circumstantial evidence and that question does she know is not really a question about her epistemological state it's a question about her belief contrast that with the following case somebody alleges that her husband is cheating and I say yes but do you know her husband is cheating in which case I'm asking about what is the case rather than about the belief or you can imagine a case where some train accident is reported and my son was on the train and I say do you know that my son is alright and I don't actually give a damn about your epistemological state the only thing I'm interested in is is he okay so it's arguable that when we talk about knowledge in a practice situation normally we're interested either in somebody's stated belief or we're interested in the actual facts it's very very unusual for us to ask in ordinary life whether something is a case of knowledge when we already know that somebody believes something and we already know that it's true it's the kind of question only philosophers ask and you might wonder in that context whether we're actually likely to get any single consistent account of knowledge why should we assume that if the word knowledge has these different roles in language that there really must be some single unitary essence of what knowledge is which will give the answer to all of these questions maybe we'll find that the concept of knowledge as we use it in ordinary language varies depending on our purposes now this is the kind of message that's very much associated with the later work of it constant in his book philosophical investigations we shouldn't just assume that because we've got a word knowledge which seems to be a noun for a certain kind of state but there really is some sort of essential state that it picks out well of course however we choose to use the word knowledge we can still ask in any particular case whether P is true and this brings us back to GE Moore and his hands so let's suppose that after all this discussion of what knowledge is we end up saying well actually we do want to use the word knowledge in a way that reflects our use in ordinary language we want to allow that I can know the Train is time to leave at 1736 even though I might be dreaming maybe we want to allow the contextual list to apply different levels of knowledge in different different circumstances and we certainly don't want to insist that only super rational beings who reflect on all their beliefs and justifications can know things quite the reverse we want to accept that dogs and cat can know things we're happy to say that ordinary unreflective people can know things when there are reliable connections between their faculties and the truth even if they can't explain what those connections are so this naturally leads us back to externalism as an attractive account of knowledge this enables me to claim that I do know this is a hand even if I can't prove it and even if I can't know that I know it whether I do in fact know it depends on how things stand outside my mind the various causal links between the world and my perceptions and so forth as long as they're working fine then I can have knowledge just as the dog can have knowledge I don't have to be an expert philosopher or an expert in human perception for my perceptual faculties to operate correctly and give me knowledge but the skeptic is still lurking in the wings let's suppose we accept all I've said suppose we accept that the word knowledge as it's used in ordinary language fits with this sort of externalist account and can quite properly be used in the various loose waves I've described that doesn't actually defeat the skeptic because the skeptic can say well look if what you say is right if your beliefs are in fact true then I'll accept that you know all these things in this ordinary language sense but I still challenge you that those beliefs might be false so even if skepticism can be answered from a God's eye externalist point of view God can look down and say Millikan's faculties are working fine so he does in fact know that there's a hand there the question whether they're actually true can still be asked from the internal perspective I can't necessarily know that I know so I can still raise skeptical problems about things that from a gods eye point of view I do supposedly No so is there any answer to this kind of skepticism well surprisingly perhaps one rather prominent answer which aims to show that we can be confident of some of our basic perceptual beliefs has come from the direction of the analysis of ordinary language so suppose I refer to this and I call it a hand and I conclude that there are two hands are they really are they really hands you might think no for all you know you're a brain-in-a-vat you're dreaming whatever well okay let's suppose I am in fact a brain you know that okay I'm a brain-in-a-vat I look at this I look at this I think there's something there let's not worry about where there is I'm aware of something and I call this a hand and if these are actually hand images then when I use the word hand to refer to them I'm referring to hand images okay but if when I say hand I mean a hand image then this is a hand after all even if I'm a brain-in-a-vat this which I call a hand is a hand good maybe from a God's eye point of view they're just hand images from my point of view that's what I call a hand so if even if I am a brain-in-a-vat I can say with GE more there's a hand there's another if the meaning of hand is determined by what we're actually referring to it looks like the skeptic can be defeated or at least I need not worry about whether this is really a hand this must be a hand because that's what I mean my hand and that's the kind of approach that Putnam suggests now you might well think that's a little bit too quick it's not really a very satisfactory answer to the skeptic I think that worries right here's how I might spell it out when I look at this thing I think there's an object there which is actually moving in space and whose movement is systematically correlated with my perception in such a way that my perceptions give a directly reliable indicator of where it is I have an idea of the sort of causal interaction which is responsible for these perceptions in terms of light shining on my hand bouncing off I see it with my eyes and so forth and that's a very different picture from the picture of some mad scientists manipulating electrodes or running some computer program which is bringing it about that my perceptions correlate as though there were an object there so maybe I can make some sense of a God's eye point of view from which it would turn out that what I call a hand is really nothing like what I take to be a hand in that case the Putnam approach can be challenged it won't follow that when I say there's a hand I can be utterly sure that that's true if what's really there is nothing that bears any systematic correlation to what I'm perceiving except through the manipulation of some mad scientist and there's another problem with putnams approach let's step back from the VAT for a moment and return me to real life okay I know what a hand is there's a hand I'm walking along in Oxford one day on my way to a lecture and I get kidnapped and invited some mad scientist extracts my brain and puts it in a vat I forget about all this of course I'm given the illusion of coming to a lecture I look at this and I say here's a hand but actually it's just a hand image and now it looks like putnams approach isn't going to work because I learnt the use of the word hand by referring to real hands so when I say hand I mean a real hand I don't mean a hand image in which case I can raise the skeptical worry maybe this isn't a real hand maybe I am a brain-in-a-vat so needless to say the bogey of skepticism comes back as indeed it usually does there's no magic bullet to defeat the sceptic and at least Putnam hasn't given us one finally I want to go back to induction the Putnam approach might lead you to the following thought leaving aside the worry about being kidnapped and inverted suppose we worried that our whole life is lived in a vat or in the matrix or something like that it's tempting to think well suppose I am a brain in a vet suppose I am in a matrix why should I care I'm living my life perfectly well maybe it is in the matrix but that doesn't stop me enjoying the things that I enjoy doesn't stop me getting satisfaction from the company of matrix people eating night nice matrix food or whatever you might however wonder where this leaves issues about moral obligation to those matrix people but let's put that to one side all these matrix things they may not be real but they bring me the same pleasure so why worry about it why not just go on as before even if I am a brain-in-a-vat even if I am living in a matrix now seem like this vertical skepticism that is worrying about inference from one level the level of perception to some deeper level the level of objects can seem not so worrying after all and there's a contrast here with horizontal skepticism the kind of skepticism that you get in the problem of induction and that will remain even if you're happy with living in the matrix or as a brain-in-a-vat everything so far might have got gone on fine but how can I be confident that it will carry on going on fine this problem the problem of induction arises whether I'm in the real world or in a matrix or a brain-in-a-vat so there's a sense in which horizontal skepticism that is skepticism about inferring more of the same though it seems less radical is actually potentially more worrying than vertical skepticism and this gives me an excuse having gone back to human induction to look at the kind of response that he gave and is commonly given now to these kinds of sceptical worries and that is to focus on the ethics of belief what should we believe Descartes started out his skepticism saying that he shouldn't believe anything that is less than certain the message of all the discussion about skepticism is that if we do determine ourselves not to believe anything that is less than certain we might end up believing virtually nothing at all but is that possible are we able to believe nothing at all and should we even go along with it why should we condemn ourselves to believing nothing that is less than certain well I think most philosophers would agree with Hume that suspension of all belief is just impossible for us the way we're made we just cannot help believing certain things and it's probably a good thing that we're made that way because if we weren't then we'd be in serious trouble notice also that this approach goes well with contemporary externalism the thought is that we shouldn't aim for all our beliefs to be such that we can justify them internally we shouldn't expect to be able to workout internally the justification for everything we believe perhaps we have to rely on our animal nature that leads us inevitably to believe certain things and to trust in general that our faculties are thankfully more or less reliable of course that doesn't mean that we should become undiscriminating and they remain big questions about how to distinguish between things that remain justified and things that aren't but if we want to hold out against the sceptic we probably have to be prepared to accept standards that are less than absolute thank you [Applause]

Channel: Philosophy Overdose

Views: 3,967

Rating: 4.858407 out of 5

Keywords: Philosophy, Analytic Philosophy, Epistemology, History of Philosophy, A. J. Ayer, Theory of Knowledge, Internalism, Externalism, Coherentism, Foundationalism, Contextualism, Gettier, Belief, Truth, Justified True Belief, Wittgenstein, Certainty, G. E. Moore, External World, Brain in Vat, Hilary Putnam, Putnam, Descartes, Rationality, Introduction, Introduction to Philosophy, Relativism, Objectivity, Blindsight, Conceptual Analysis

Id: rBZJIjR8BvU

Length: 53min 50sec (3230 seconds)

Published: Fri Dec 20 2019