Hume 1: Empiricism and the A Priori

welcome to this lecture on David Hume who's bringing us closer to the contemporary period so we'll be spending two weeks on David Hume and then moving on and talk about Immanuel Kant's and then eventually coming into the contemporary period so we're inching ever closer of course David Hume is the last of the so-called great British and persists even though he was Scottish and he dies in the year of the American Revolution Hume is one of these very interesting people he never held a philosophy teaching job in the way that we contemporary people think most great philosophers would have been located at a university his views often got him in trouble because of his critique of religion in views about God and miracles and so his his work was held with great suspicion and Plus as we'll see his views run very counter to common sense nonetheless many people regard David Hume to be the most important philosopher to have ever written in English and that's quite quite a claim to to make so whether you agree with that or not it's well worth knowing the outlines of Humes views so let's go ahead and begin with a little bit of just reminding ourselves of where we are in this story we're telling here so we have Newtonian physics which really culminates the push towards mechanism and mathematical physics which is being developed at this time and Locke had given an account which many people thought did a great job of providing the philosophical underpinnings to the kind of new science that was being developed by Newton in Galileo and it certainly seems as though a disappearing time empiricism is gaining the upper hands so rationalism especially Aristotle's version of it and Descartes version of it seemed to make several predictions about the world which are coming under scrutiny and this empiricism of myth seems to provide an alternative more successful way of thinking about these issues now we can think of humans coming along and kind of raining on this parade so Hume is an empiricist but he wants to show that there's something deeply troubling about empiricism which is that it leads to a kind of radical kind of skepticism and of course everything about Hume scholarship is is controversial so that's why I say it's a kind of skepticism it depends really on what your views are about this kind of stuff but certainly at least in Humes on mine wasn't the same kind of skepticism as you might find in the ancient Greeks okay we won't be dealing too much with these interpretive issues because again at the introductory level what we're aiming to do here is get the overall shape of Humes philosophy as best we can and by doing that we're going to be drawing a cartoon character of stuff that is much more subtle underneath but we'll try to maintain the standards nonetheless okay so let's start by just reviewing Humes version of empiricism because there is something which is distinctive about it and something which is also continuous with the earlier versions of empiricism developed by Locke and Berkeley so Humes tells us that the mind could be divided in two categories what he calls impressions which are the actual experiences that we have for instance when you bite into an apple and you taste the Apple when you see a sunset when you feel a pain being angry jealous hungry or sad so all of your ordinary kinds of experiences that you have of things which seem to be indicative of an outside world those are what called what Hume calls impressions and they're contrasted with ideas which are copies of impressions so for instance my memory of the taste of Apple or my concept of that taste is something which is copied from the actual taste my idea of anger jealousy hunger and etc so what Hume is added here something which sometimes people call the copy principle which is his idea that the concepts or the ideas that we used to think are actually copied from sensory impressions and so these are the two components of the mind and it's important to keep yourself clear on the fact that human explicitly think of these as kinds of perception which is to say that they're mental and they are merely distinguished by from each other by their force or via so it would be wrong to take the word impression that Hume uses their it in a certain way namely as indicating that there are objects outside of us which are impressing themselves on us that would be wrong since human remains officially neutral about whether or not that there is an external world which is impressing itself upon us rather what he's trying to indicate is that impressions seem much more forceful and lively than the ideas and so this is you know pretty easy commonsensical idea that that Hume is developing here if you were to be kicked in the shins the impression of the pain the actual experience of the pain is much more forceful in your conscious experience than when you reflect on it an hour later or a week later when you remember getting kicked in the shins or when you're thinking about that kind of pain a sharp throbbing pain thinking about it later is not the same as experiencing at the time and they're similar is you can kind of recall what the pain felt like in a dull kind of faded lifeless kind of way the same with a taste so you may love the taste of granny smith apples let's say when you bite into a granny smith apple there's something very forceful very lively about the taste it impresses itself upon you the taste is present in a in a certain kind of way later when you think about the taste oh I really love the taste of sour apple of especially granny smith sour apples you can kind of get the sense of the flavor back but it's not as forceful or lively as it is when you were actually undergoing these things so as hume tells us ideas are what we would call are dull and lifeless copies of the original impression so your thoughts are composed of these concepts these ideas which are derived from impressions but they're dull and lifeless so the sentence you know the thought that you have that sour apples are delicious is nothing like the thought you have when you bite into an apple and think this is delicious with with this they're picking out the actual taste of the Apple as it occurs but of course both of these things as I stressed at the beginning are merely mental phenomena Hume is not taking a side in the debate over the existence of the external world so we have descartes on the one hand who says we need God's justification to believe that there are things outside of our sensory experience Locke who says no as part of our common sense there are things out there which causes Berkeley who says well we have no reason if we're empiricist to believe in the external world so we should just accept that everything is in our experience and in a sense Hume is more on Berkeley side although he's not an idealist he's not someone who says all that exists or ideals he's someone who thinks that we can't know whether our ideas and experiences represent something external to our mind and so it's best to just stick with what we can discern which is what kinds of experiences we have and how they're related so he resolves to just explore the mind what can we know about the nature of our own mind okay so well he's going to use this version of imperson especially the the copy principle to develop a theory of meaning so it's pretty clear that words stands for ideas in Humes sense so when you say the word dog what that stands for is your idea of a dog which is itself copied from your impressions of dogs so Hume endorses and names the distinction between simple and complex ideas and so just to remind you of what those are we talked about them in the Locke lecture but just to bring it up again complex ideas are composed of simple ones and simple ones are either traced back to an impression from which they were copied or else they are meaningless nonsense so Hume actually thinks that this way of explicitly explicitly formulating empiricism can show that a lot of what has passed this philosophy prior to him is actually playing games with words so that philosopher's sound like they're talking about something when they really aren't so for instance my concept of a unicorn is not meaningless even it's a complex idea composed of parts horse and horn and very shapes and colors and so on and all of those are things which I have had impressions of so I know even though there are no such things in the world as unicorns I have a meaningful thought when I think about them because each part of that thought is meaningful on the other hand takes something like plato's forms plato's forms are defined as being outside of the realm of impressions you can't have an impression of a form forms have to be apprehended by reason in some other kind of way and there's no real direct sensory experience that one can have of these things so according to this criterion then forms and Plato's terminology are strictly speaking meaningless the word form stands for an idea that idea doesn't have an impression that is copied from there's no impression we can trace back the idea to and so form is a meaningless concept it has it has nothing in it that we would like to save or learn from and so should be discarded and is a mask by behind which people could hide and sound like they're talking about something important when they really aren't and basically what Hume is going to be doing is using this criterion using this idea that if can't find an impression for your ideas that idea is meaningless as a way of figuring out which ideas are meaningful and what we can really know about the world that's really firmly based on an empiricist in epistemology so I said this already again but just to reiterate this is the key sort of pivotal point in human selasa fee if an idea cannot be traced back to an impression that idea is meaningless and should not be used so that's going to be the Sith which he's going to be chopping down the various philosophies of the path past all right so now that we've we sort of know what human means by empiricism it's the doctrine that every meaningful idea is copied from a sensory impression in that all human knowledge is somehow going to be based on these ideas and impressions so Hume goes on then to distinguish two classes of mental phenomenon those that he calls relations of ideas which are all the things which would be classified as a priori reasoning and matters of fact which are all empirical knowledge and so we're going to spend some time in this set of this first part of the lecture talking more about what the relations of ideas are and how they work on humans view and then we'll turn in the second lecture to talking about matters of fact and what's called known as the problem of induction the problem that Hume seized with causal reasoning so to decide which so everything that we know this is sometimes by the way what's called Humes Fork like a fork in the road since these are the only two options which are available this is everything that human beings know must be one or the other of these two things and hew sake right Irian for determining when you say I say you know something or some piece of information you want to classify which is which so roughly the that Hume has is that if the negation of the proposition in question is a contradiction than it is a relation of ideas and this is sort of what's definitional of relation of ideas relations of ideas are the kinds of things which people typically thought could be knowable by reason and Hume recognizes that they do seem to be different there is a sense in which saying that two plus two is four seems special doesn't seem open the change and etc and he wants to try to explain how that is how it is indeed special in a sense but doesn't rely on some deep metaphysical principle like Plato thought namely that there are these innate ideas that are indicative of necessary and universal truths about the world that we live in so we're going to talk more about this but the basic idea is that you know that something is a relation of ideas when you can know it without checking and if you deny it that thing would turn out to be contradictory if you can deny the thing in question without contradiction then you know that it's a matter of fact so let's spend a little bit of time applying this rule and we'll talk more about this as we go through it but this is just for us to start to get the hang of what's going on here so here I have my relations of ideas on the left and my matters of fact on the right and we're going to consider some piece of information like that all bachelors are unmarried and we want to know is this a relation of ideas or is this a matter of fact well how do we know well remember what we just said is that if you can deny the thing without getting yourself involved in any contradiction then you found a relation of ideas if you can imagine it being false and there's nothing contradictory about that then you've found a matter of facts so all bachelors are unmarried males can we imagine that being false well to do so we'd have to imagine a person who was both a bachelor and who was also married now can you have a married bachelor too many this sounds like a contradiction saying that a bachelor can be married and so bachelors being unmarried is one of the prototypical kinds of things that people think of as relation of ideas you can know it without checking you don't have to check every bachelor to make sure that they're unmarried and if you deny it you get something which is contradictory okay so let's do another one here's something which is related to that the claim that all bachelors are messy so let's again see if we can imagine the that being false and whether or not we get a contradiction so to imagine that being false I would have to imagine some bachelor who was messy excuse me who wasn't messy some bachelor who was not messy in other words a bachelor that was clean and of course there's nothing contradictory about the idea of a clean bachelor we have examples of bachelors who are neat and tidy if you don't know any one famous example is Jerry Seinfeld they did a whole episode of Seinfeld centered around the joke that he was thin neat and also a bachelor and people wondered what that meant so all bachelors being unmarried seems necessary it doesn't seem like you can deny it without saying something contradictory whereas all bachelors being messy seems not to be necessary and seems as though you could deny it without getting yourself into any trouble okay so let's do another one what about all triangles have three sides well to imagine this being false you would have to imagine a triangle that didn't have three sides that had some other number of sides can you do that can you imagine a four-sided triangle try to picture what a four-sided triangle might look like or if you can't picture it just try to conceptually wrap your mind around a four-sided triangle well many people think you can do that so there would be something contradictory about the concept of a four-sided triangle and so all triangles having three size is again something that's a relation of ideas let's try another one what about all dogs have four legs is this one a relation of ideas or a matter of fact well again you ask yourself could I know that all dogs have four legs merely by thinking about what a dog is or in other words could I have the experience of seeing a dog that didn't have four legs and of course well you can dogs having more or less than four legs is common you can have a three-legged dog a two-legged dog you could have a genetic accident and have an eight-legged dog and of course having a dog with a legs doesn't make that dog into a spider it just means it's a weird dog so there's nothing contradictory about having a four-legged dog now how about this one this is going to be the one that Hume is really interested in so what about the Sun will rise tomorrow can you imagine the Sun not rising tomorrow well certainly seems like there's nothing contradictory about the Sun rising tomorrow if by that you just mean the Sun blows up the earth blows up the earth loses its orbit and so go spinning off into some other direction and doesn't have the Sun close enough to be rising and setting in the way that it appears to do when we're here on earth and this is going to be important for Hume latter when he tries to show that induction is very problematic because no matter how great your sample size you never get to something that's certain but we'll deal with that later for now we want to just put up a list of the various things which count as relations of ideas and matters of facts so here are the things we're just talking about well add a couple more apples being red that's clearly a matter of fact rent in New York City is expensive that's a matter of fact nothing contradictory about the idea that rent is hot low or high subway this is a fact an old slide the subway is even more expensive now so it's clearly nothing it's contradictory about that now here are the interesting ones that we're going to talk about later and part of what we want to understand is why fire causes pain and objects when dropped will fall and the future will resemble the past these things get put on the matter-of-fact side as opposed to the relation of ideas side now what does go on there are these kinds of things here which you could what you can predict that they'd be there so all bachelors are unmarried males well that's just definitionally true while triangles have three sides that's also definitionally true a squared plus b squared equals c squared that's the Pythagorean theorem here's Humes own example three times five equals half of 30 now here a couple of logical sentences for any sentence s either S is true or false for any sentence s S can't be true and also not true at the same time those are the laws of non-contradiction and the laws of the excluded middle which we've already talked about in previous lectures so now notice the way you classify these is by whether or not you can negate it whether you can imagine it to be false without contradiction and whether or not you require checking of the world now you should notice at this point that what humans doing is sort of recreating de cartes method of doubt but with a different purpose in mind so when Descartes was doubting something he was I'm trying to see if he could imagine that that thing was false and if he couldn't imagine it being false then that thing was certain now Hume isn't doing the exact same thing but what he's doing is using this epistemological criterion namely contradiction and imagining to be false as a way of sorting things into things would seem necessarily true and things would seem only contingently true where contingent just means that the truth of that thing is dependent on something else so Hume now needs to explain what's going on on the left side here member he's an empiricist so he thinks that all knowledge comes from experience and yet on the left hand side of the distinction here the relations of ideas don't seem to come from experience in fact these things seem to be necessary they seem to be contradictions when you deny them and these were the things which people like Descartes and Plato the rationalist took to mean or be an indication that they were somehow special truths about the nature of the world which we had access to by reason so Hume is not a rationalist so he wants to explain what's going on there in a way that's compatible with his empiricism and this is the way that he does it so he says well look there are two parts here in your relations of ideas there are the ideas and then there are the relations between those ideas so what's going on then for Hume is that so take bachelors being unmarried for example you have the concept of a bachelor and the concept of an unmarried male and those two concepts are related to each other in such a way as to make it impossible for there to be a married bachelor now what is this relationship that holds between bachelor and unmarried males well Hume says it's a definitional relationship bachelors are simply defined as unmarried males and that's what makes it true that all bachelors are unmarried males is the relationship that those concepts or ideas have to each other not some fact out there in the world so bachelors in a real sense don't exist in nature and this is something you can think about but ask yourself if you have a group of dogs and the dogs are male and they're unmarried should they be counted as Bachelor dogs now of course that's a bit of a joke because dogs can't engage in marrying they don't have a system or institution of a social practice by which they engage in promise making between partners to love honor respect etc so no dog can be married and so they don't count as unmarried in the right way and we wouldn't want to go around saying that penguins even though they mate for life are bachelors before they meet their penguin mate for life Bachelor is something which is defined as being relative to marriage and marriage doesn't exist in nature so in a real sense if every human being died tomorrow there would be no bachelors left on the planet even though there were dogs and penguins who were technically unmarried so bachelors exist because of a relationship between the concepts of unmarried and male which says that you only count as a Bachelor if you're unmarried and male Humes idea here is to extend this to every relation of ideas so everything on the left is simply true by definition according to him and it is true that their truth is independent of experience in the sense that one does not need to go and check to see if they are true notice we've already thought about that bachelors being unmarried triangles being three-sided is not the kind of thing which you need to go and inspect all the members of that class to determine whether or not this is true of them so nobody would get a grant from the government to determine whether it's true that all triangles are three-sided or whether all bachelors are unmarried males you can tell already that all bachelors are unmarried males simply by knowing the meaning of the word Bachelor you can tell already that all triangles are three-sided simply by knowing the meaning of the word Bachelor so rather than telling us some fact about the world what this is telling us is some fact about the way our ideas are related to each other in this definitional kind of relationship they don't tell us anything about the nature of reality out there now Hume extends this to include even math and logic so 2+2 being 4:15 being equal to 1/2 of 30 the law of non-contradiction all of these things are merely definitionally true according to you they are knowable in a special way because they're married telling us how the concepts are related now that's a hard thing the grass when it comes to things like 1+1 equally - how is that merely definitional well Hume thinks is part of the definition of the number two that one plus one is equal to it it's also part of the definition of the number two that when added to itself you get four it's also part of the definition of the number two that when added 298 you get a hundred and so all of these are arithmetic 'el truths that the number two figures in actually turn out to be part of the definition of the number two and what mathematicians are doing according to Hume is simply working out the consequences of these definitions whether they know it or not so what seems like a novel discovery in mathematics is really just a discovery about where the definition of something leads you if you apply it consistently now that's an interesting way of thinking about math and it has the advantage of not having needing to invoke any kind of ontological assumption about numbers so in a real sense you can say numbers don't exist for Hume outside of the human mind what the number one is is simply this relationship it has with all of the other ideas that the person has so if the if every human being died tomorrow then they're simply one being any numbers or mathematical truths on this view even if there were two rocks sitting on the some grassy knoll for instance and a third rock rolled down the hill and bumped into those further two they would no longer be the case that two plus one was or that there were three rocks there because these things are are true only if there are human beings that have the right kinds of ideas that are related to each other the right kinds of definitional sets so in nature mathematical truths aren't there and human really does think that mathematics doesn't describe the way the world works that's not the point of it it's not to try to capture or describe the way the world works but rather captures or describes the way that our ideas our concepts are related to each other this is something that we're going to see when we turn to the section on Conte Conte is very keen to challenge this idea that mathematics doesn't add anything new to our knowledge about the nature of the physical world but it's really rather just an exploration of our own concepts in the way that those things are related to each other okay so as I said this is a very nice way for an empiricist to capture most of the things that rationalist want to say about numbers without their metaphysical assumptions so Hume can say two plus two is four is knowable with certainty because we can expect the concepts and know that they must be true he can say that it's necessarily true it will always be true as long as these concepts are around and related in that way which seems like they are so that Plato said two plus two is four and Hume says that two plus two is four and even though there's two thousand years separating them they are nothing has changed about those relationships so they're necessary they're Universal they're knowable with reason but of course none of this business about non-physical eternal and unchanging objects is being brought up so who doesn't have to say that there are these non-physical things because you don't need the objects out there to make it true that one plus one is two all that you need are the relationships between the concepts in the human mind so Hume thinks this is a perfectly good way of preserving the seriousness of math and of capturing the surface features that rationalist thought that mathematics had but in a way which is perfectly also at home with his empirical views and his denial that there's anything more to real knowledge than we can we can experience and you should notice that reason now is relegated to a relatively minor task it's not the job of reason to tell us about the world it's really the job of reason to inspect the ideas we have and the relationships between them so that when I have my concept of a bachelor I'm able to inspect it and see that it's related to the concepts of unmarried and male in a certain way and that vixen is related to female Fox and there are certain these definitional relationships which I'm able to figure out just by looking at the concepts but I haven't learned anything about the nature of the world I've just been examining concepts and how they're related to each other so reason has this relatively minor role it's a far cry from the primary role that Descartes and Plato gave to reason in figuring out the way the actual world we live in works by first coming to understand necessary and universal truths about it so Humes full of empiricism it has this very clever element to it and it's not it's something that's very popular and if you go on to study more philosophy you'll notice a large similarity between Humes views that we're talking about here and the logical positivists of the early 20th century who were also empiricists and did a lot to revive and clarify this notion turns into something very important so we'll be looking at some of that as we go into conduct in the next section

Channel: Richard Brown

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Keywords: Hume, 1

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Length: 33min 0sec (1980 seconds)

Published: Tue Nov 08 2011