Sensation and Perception

hello and welcome to the lecture for a week three of my philosophy of mind course this week we will be talking about sensation and perception and this is a really interesting and exciting time to be discussing these kinds of issues because there's a lot of really exciting work that's being done right now currently this is a center of renewed interest among contemporary philosophers so this is going to be an introduction to the philosophy of sensation a perception and like all of these things you should take it strictly speaking as an introduction we're going to cover a lot of material and if you wanted to be serious about any of this you would have to then go and take a complete and entire course on any individual topic that will brush past in this discussion so feel free to ask questions and get involved so starting from a common-sense standpoint we can say that the senses are what allow us to perceive the world that we are in and immediately this brings up two questions so on the one hand we have a question about the senses how many are there how many could there be how many kinds of senses are there that's one question and then there's another question about any given creature in the particular senses it happens to have for instance you might think vision is a kind of sense but if you're born without eyes you may not have that type of sense you may have different particular senses and so there's an interesting question about how how we count the varieties of senses and we'll talk about that in great detail in the in this lecture on the other hand we have a question about perception which is you know we say that we perceive things in the world and a properties of the world but what exactly are the objects of perception which things in the world are we perceive leaving and that's going to be the second half of this lecture so roughly speaking the plan then is to divide these as much as possible into these two categories on the one hand address the questions about how many senses how many kinds what kinds and that sort of thing and then on the other hand address the question of well what kinds of what are the objects of perceptions are there something mental that we perceive or do we somehow perceive the physical things themselves now before we begin though trying to clarify these questions and make sense of them I want to say that we're going to take the topic of consciousness insofar as that's possible and set it off to one side so we're going to spend two weeks on the topic explicitly of consciousness and so in week four we'll talk about general properties of consciousness like subjectivity and the popular phrase what it's like for one introduced by Thomas Nagel we'll read that paper what it's like to be a bat what is it like to be a bad question mark and then we'll talk about some you know varieties of concept of consciousness and then we'll turn to the next week questions of whether perception is always conscious unconscious perception can you have a consciousness that you don't know that you have and all of those interesting questions which are surrounding issues of perception and consciousness are in are going to be put there and there's going to be some other questions as well like the relation of consciousness to thought consciousness the concepts and can they influence each other and such like that so there are very interesting questions but we're going to save those for the for the following two weeks and in this section we'll just focus on these two questions that we have above us what do we perceive and how many kinds of senses are there or could there be okay so starting with the first question there you could start with the most obvious one since you know we'll start with humans and work our way outwards so you might say look well how many senses do human beings have and so here I'm trying to ask a question about not only a particular human being but us as a species as a kind of thing in the world how many senses does the properly functioning average person in half that's one question and interestingly and not this question was really first explicitly addressed by Aristotle and his claim was that there are five senses and we know these five so vision is one of them hearing or auditory sensation what we call audition that's also another one then they're smelling or olfactory sensation or olfaction and then there is feeling the sense of touch which we call tactician and that's where we get tactile from and then there is the sense of taste or flavor which we call gustation so Aristotle's answer was that there are these five senses and there are only these five senses in human beings now these senses allow the animal to perceive the world that it's in and according to Aristotle having a perception or having a sensory organ in being capable of perception is what distinguishes animals from plants so Aristotle denies that plants have anything like sensation or perception and that might be something that we'll look at later the question of is there anything like sensation or perception going on in plants marisota would say no so he would say look this is what makes us the way that we are and of the five it seems like he would have claimed that touch is the most basic and fundamental sense and the reason why I say this is because he claims that it's the sense which every animal has right even lowly creatures like slugs and so forth I'm have the capability of sensing their environment by contact so that's that's an interesting claim that he makes that you have to have some kind of sense organ as well as in be capable of perception in that every animal every kind of animal work not every particular individual animal at every kind of animal it's exactly an animal because of having this ability ok so now if you wanted to know how you know how many kinds of sense is that there are Aristotle gives you an answer he says well what we call a kind of sense is individuated or spliced off from the other ones by the kind of property in the world that it allows us to be responsive to so the idea is that there are these various properties in the world and the sense organs are the things which allow us to be responsive to these properties or and that's what allows us to perceive these things in the world so that each sense is going to deal with a certain kind of thing out there according to Aristotle now he further distinguishes what he calls the common sensible from proper sensible and to start with common sensible first what he means by saying that something is a common sensible is that it's the type of property which is detectable or sensible by more than one sense organ and so one obvious example here is shape you can see the shape that an object has and you can also go and touch it and you can therefore feel what the shape of an object is there's an interesting question about the relationship between the two of them that we'll come back to but for now we can just point out that this these properties the proper excuse me this property the property of shape seems like it's sensible in more than one way it's not accessible in only one particular manner now Aristotle says it turns out that there are a number of properties in the world that are commonly sensible like this and he points that to things like motion you can see something moving but you can also feel it like if you're sitting you experience acceleration so that seems to be something that's detectable by multiple avenues and he also points to magnitude which is how big or how heavy something is and then number and unity so these were according to Aristotle things which we could sense via more than one of our five senses but each sense though even though some properties are commonly sensible each senses associated according to Aristotle with a limited range of properties which it's sort of specially suited oral especially responsive to so for instance in the case of vision we have a sense organ namely the eye right so the eye is what allows us to sense the the visual properties and the the things which we thereby come to perceive this way the proper sensible at least vision is color so that according to Aristotle when you're perceiving color it involves something to do with the eyes and then that in somehow creates or we'll talk more about what this means exactly I'm in a more general way in a second but you're in contact with the property of color and for each sense then there's something like this so for instance in hearing you have a sense organ namely the ear and that sense organ is detecting or somehow sensitive to a certain property which makes it the kind of thing that it is and that particular property sound so according to Aristotle you are perceiving sounds by using the sense organ the ear right this is I hope so far very fairly common sensical that this is why it's lasted for so long okay and then so on for smelling you have again a sense organ the nostrils the nose and you are it the proper sensible here is odor smell and then the same for taste or gustation the proper sensible here according to Aristotle is flavor so these four have one and only one proper sensible which according to Aristotle means for instance that while vision uses the eye to detect or somehow let you perceive colors that you cannot perceive color by smell and you cannot perceive color by sound and you cannot perceive color by taste because that's not the kind of property that is revealed to you in those other ways according to Aristotle now of course I hope you see where this is going almost every one of these claims is going to be challenged at some point in a lot of what the philosophy of sensation and perception is is sort of trying to figure out to a large extent whether Aristotle and common sense which he sent symbol symbolizes here has got things correctly okay so I've been saving the last one here because it's the most complicated on this view and that's the feeling that the the sensation of touch which according to Aristotle we use you know are our hands and skin that's the exterior of us is where the organ of that is located and there's not a single proper sensible according to Aristotle here so there's no one single aspect or property of the world that touch gives us gets us in contact with but rather there's multiple of them and so Aristotle says look there's a lot of them any sort of lists all of them and we're not going to bother about this because this is a class on Aristotle's views this is just sort of I'm taking Aristotle to be a stand-in for the common sense view here and so after going through this he says look we can basically see that all of these are somehow reducible to a basic set so with touch you can tell you can tell whether something has a property of being dry a solid right right by like touching it you can tell us something is a liquid or if its fluid by touching it and you can also detect heat and you can also detect cold so aerosol says well you know a lot of the other things that we sense by touch are really combinations of these in various varieties and we'll kind of leave that there okay so that's in very much large extent the traditional view about the senses and the way they relate to perception so on this very traditional view the senses always involve the use of an organ in order to allow the creature to perceive some aspect or property that the world has okay so we're going to talk about whether this view is right in multiple ways so the first what thing we'll talk about is whether humans only have five senses so one thing and this if all of this stuff right here comes from an article by Fiona Macpherson who's done some really excellent work on this and she has a really excellent anthology on the philosophy of the senses one thing that we notice about the bat is well if you look at fiction it's just replete with examples of possible other kinds of senses so just take one example x-ray vision the Superman variety that seems like a special kind of sense which humans don't have but I don't know it seems possible mind reading another very traditional kind of sense you might think the ability to sense other people's thoughts and that's always something popping up in fiction then there's the ever-popular so-called Sixth Sense the ability to precede ghosts or to see into the future or something like that now remember I'm not claiming that any of these are in fact real what I'm saying is that in some sense or other pun sadly intended in some sense or other these things have at one you know time or rather been thought to be possible senses that human beings could have even if they don't in fact have and then we can add to this some some more science fictiony examples like the predator infrared kind of vision if you remember the movie the predator and of course have you seen the movie the terminators now if you sort of just forget for a second that the Terminator is a machine and ignore the question of whether machines can have perception something we'll talk about towards the end of this class but for right now just ignore it and just imagine the kind of perception that the terminators depicted as having so he's able to look at an object and determine its composition chemically and that sort of information is available in perception you might think in the way that the movie is depicted to us and then of course there's also another one from fiction here which is the spider-sense and this whole list comes from Macpherson's introduction to her anthology so now what is the point of this list well I'm not saying that these are real like I've said already what I've said is well there's doesn't see me anything absurd or impossible or anti common sense about the idea that there are more than five senses in fact it seems like people are always coming up with ways that we could possibly have more than five senses so then the real question is are there real examples of extra senses besides the standard so-called traditional five senses so to begin with we can talk about things like senses of humor or sense of justice sense of fairness or what is sometimes called the moral sense my ask yourself well I don't know is there such a thing as a sense of humor is that really a sense is there an organ some faculty that we have which is dedicated to picking out properties of being funny being not funny well many people sort of go where now know that that's a sort of metaphorical use of the word sense although you know there might be some people who could defend this kind of view now the moral say there are actual people in the history of the world who have said there is such a faculty that works like a sense where allows you to pick up on certain properties of the world like being right or being wrong being good or being bad being just or being fair and some of these people you know if you look at take an ethics class you'll talk about them and that's highly debatable whether this counts as a sense but some people might say look what the emotions are or something like an emotional faculty looks like it might be responsive to these kinds of properties like there might be a kind of feeling emotional feeling one gets when one sees injustice and that might be the source of our perception of injustice so we'll leave that question aside but it is an interesting question and it's one that we're going to come back to when we get to the stuff about thought and so forth because you might wonder can you really perceive injustice is that the type of thing that is that the type of property which could even count as a perceptible property so let's table that for a second and look at some other kinds of examples now traditionally what people do is they appeal to some current empirical findings so one of the most easiest places to start here and one of the most widely discussed possible others kinds of senses is what's called proprioception so this in just normal terms is the ability of you to know where your body is in space and what it's doing in the kind of immediate indirect way so you know a way to get a feel for this is if you close your eyes and stretch out your arm think about the way that feels so just be quiet for a second and focus on that if someone to ask you is your arm stretched out or not you'd be able to answer that without looking without touching yourself without hearing anything without smelling something so what what allows you to know how your arm is extended or not are you making a fist is your finger pointed out as in the crooked position well if you make these various movements and pay attention to your experience you might notice oh we're very good at telling where our body is in space so some people say look and you know in fact the reason is there are these nice little receptors located in the muscles and these give us information so it looks like there's all the you know there's a kind of sensory organ there there's a kind of perceptual thing that we're getting in contact with where our body is in space so that's one candidate proprioception and there are some other ones which are similar to this so the other one is that you hear a lot about is the vestibular sense and this had to do with their sense of balance so we know that this has to do with stuff in the inner ear and there's a little liquid filled cavity there and if you tilt your head the liquid is turning back and forth and so therefore that's used to determine whether you're upright upside down tilted in a certain direction or whatnot we're very sensitive to these kinds of of changes so some people say well maybe what you're doing is you're sensing you know orientation as well your your balance very interesting idea here's another one is there a vulnerable sense where this is getting at the idea do we is it somehow possible that we're set sensitive to fur moans now in animals this is less controversial like dogs we know they have this kind of sensitivity to pheromones and it's a lot more controversial whether humans do and we're not here to settle that debate we're just here to sort of point out that a lot some people have said oh well okay this is a possibility for an extra sense one that we're not quite aware of or if we are aware of we haven't been able to pick it out of our experience yet so this is a controversial one and let me just mention one last candidate here really briefly and this has to do with the with touch so what scientists have discovered what science has shown us is that if you really go into the detail of what's happening at the skin level you find out that there isn't just one kind of receptor down there but that there are it looks like three different broad kinds of receptors that look like they're receptive to different things so on the one hand we have a receptor what seems like it's activated by temperature hot and cold heat on the other hand we have receptors that deal with pain and itch as it turns out and then on the third other hand the other other hand we have receptors that just can detect whether you're being compressed or not like how much pressure you're applying and that's important of course of that when you go to reach for a nice thin glass of champagne you don't crush it in your grip you know just how much pressure to apply and you're also so that these all three things then generally we would classify under the experience of touch and so some people have said well look maybe there isn't a unified thing here maybe there isn't one sense the sense of touch maybe there are three different senses the sense of temperature the sense of pain in the sense of pressure and then if that were the case there wouldn't be five senses but rather these seven because you'd have to split this last one up into two extra categories to to account for the different kinds of receptors now we're not going to answer these questions here remember bringing them up to discuss them what do we think but the questions here force us to be serious about what we mean by a sense what does it mean to call something how do we say whether or not these things count as other senses or whether touch counts as one unified sensation or whether there are these three different ones and there are various answers that people give and we can talk about those those various answers but before we do just to complicate things here here's a nice quote again from Fiona McPherson she says unquote other candidates that have been considered as being additional human senses include hunger thirst wet and dry the weight of objects fullness of bladder and also bowels I would suppose suffocation and respiration like whether you're breathing or being deprived of oxygen sexual appetite when you're feeling sexually aroused and less of fairness which I don't know if I pronounced that right but that's generally the feeling of lactating and that these all have been proposed as other kinds of senses so again these questions difficult to answer is the sense of thirst a distinct sense well there's something according to brain science that is causing this that's namely no saline levels in your blood serum so you're sensitive to that at some level and when they reach below when the saline content is too much or something like that you come to be aware of that via having the experience of thirst and so some people say well look why doesn't that count as a sense and if you think it does well then you might say well gee there's just a bunch of sense why with senses we give a pluralist about this and if you think it doesn't then it'd be interesting to hear why you don't think this is a sense so again remember I'm not trying to convince you of anything here I'm trying to say well gee and there look like a lot of candidates here and if you disagree with these being good candidate then let's discuss why ok so then moving on though to a different question we can talk about cross modal effects so now we're going to be looking at sort of a different aspect of Aristotle's view on Aristotle's view these five senses which now we've already started the question - humans have more but you take the basic five Aristotle claimed not only are they discrete in other words that they have a proper sensible that no other sense can detect but they don't interact so vision produces just color experiences audition produces just sound experiences and there is no separate combined audio-visual experience they're just the auditory one in the visual one but there is no audio-visual one somehow one that's combined or fused so this is what's called multimodal contents and that's because of the different modes here are being combined emotive sensing and by vision the mode of sensing by hearing so that's where the modal talk comes from so one thing that people talk about here is something called the McGurk effect and I don't have a video to show you but you could google it and and look at it and it's going to be sort of hard to explain I'm now realizing I should have had a slide here spelling out the different sounds because it can be quite confusing just listening to it and in fact maybe I'll go back over and the captions actually actually put them here but the basic idea is this so if you take a subject and you sit them down and you have them watch a video of a person saying a word so the trick is excuse me and it's not even a word it's a it's a phoneme so they're just making a sound and the sound that is actually being said and which the subject hears is bah-bah which we would spell is ba ba ba ba ba so you get the idea but the video which the sound is paired with and which the person is watching shows a video of that same person but saying a different phoneme so they're not saying ba ba they're saying gah G a da so they're sitting there and they're watching a person they're going gah that they're making that mouth move and they're hearing the person say ba so that's confusing right we have the BA and we have the GA now so what do you think that the person who's watching the video what do they experience well what they report and you can go and watch this for yourself and determine whether you agree or not but it's very robust finding what they report excuse me what they report is that they experience the sound da da da da so now that's very interesting what's going on here they're hearing the actual sounds the actual sounds that they're hearing are the sounds ba ba the lips that they're watching or forming with their lips the phoneme GA gah but yet the ultimate experience of those two presented together from the subjects point of view is the sound da da now the question arises is what's going on here is this somehow where you have one kind of Content the auditory content and it has the content that it does and then you have the visual content and they kind of battle and then somehow the auditory content gets changed and now it has this new content gah so that there's this interaction between the two senses and the one sense kind of modifies the other so it changes the way that it works or is it that there's a new kind of perceptual content which is produced which is neither purely visual or purely audio but it's somehow a combined multimodal audio-visual da thing it can be very hard to know what the right answer is here okay so that's a very abstract question are these things do they influence each other or do they combine to form some some new thing some further thing which is different in important respect from either of the two other things so the question is do you have two things that interact and so at the end you just have one of those two things that's changed or do you have two things interact producing a third thing so that the end you have three things instead of two that's roughly one way of thinking about this and here's another example of this and this is brought out by what in perceptual science is sometimes contrasted between taste and flavor so remember Aristotle thought that flavor was the proper sensible of gustation of our sense of taste and flavor was this proper thing now one thing that we've discovered is that well it seems like the sense of smell is importantly involved in which flavors we experience so if you have a cold and you eat your favorite food your nose is stopped up really bad the food tastes different and you can just try to plug your nose and eat something and experience it without the nose plugged and it seems different so some people think ah well you see flavour is somehow not really the product of taste but it's the combination of taste and smell and taste really is the thing that you're doing with your mouth and your tongue and then there's this smelling bit as well and the two together are we couldn't kind of confuse as one thing and we call that flavour so there's really two things there some people claim now of course other people claim well no the flavor might be this new third thing which is a combination of the taste and the smell and they combine into a new multimodal taste now so again we have the same question what is going on here is there an interaction between these two things like is there a taste and a smell and they simply push and pull in a certain way and change each other or is there a new thing that's produced kind of like you know like when you have a child you interact with another person in a certain way let's say and then you know out comes a third new thing which is kind of a combination of you two but importantly also distinct and different so is there a new thing which has produced this multimodal content which is somehow not the product of any one sense but is a product of the fusing of multiple senses that's the question that is being addressed here and we don't know the answer this is something that is currently under discussion and so again feel free to jump in into the discussion I'd like to hear what you think okay so really quickly then we can bring up to other kinds of interesting challenges so one is the issue of synesthesia which is a complicated issue and one of the reasons that is complicated is that it's people are currently so it's currently in such a state of discovery you might say that we're still debating exactly how you define it so synesthesia one common report that synesthetes make is that when they see a number for instance they also experience a color sometimes people say no they they associate a personality with the number like a seven is a real nice person and aid to the kind of hard asinine as a sneaky underhanded like that other people say oh what four is I always see it as blue or there's a blueness there or seven is red I mean I'm making these exact colors out but people will say these things that there's a kind of another property which we usually associate with a different sentence which is produced in this weird way sometimes you know reader words in a smell is produced or these various what seemed to be linkages between the senses and one of the challenges that synesthesia presents is how we handle it from a philosophical perspective when we're trying to individuate the kinds of senses that there are so if you think there are these weird kinds of interactions and so if you want to say aha well you know what what about a take I'm sorry take an example of someone who hears a sound and also experiences the sound as colored so they might say yeah the sound has a certain color well how can they experience the color associated with the sound if Aristotle's right and you know you only send sound by hearing is it one way you might put this is that the person is hearing a color what does that even make sense to say that the person is hearing a color or seeing a sound these are very strange ways of putting things but if the person is having in a visual experience in in that somehow a sound is importantly involved not as coming from the ear but somehow it's being involved in the sight then we don't know what to say and so we're still trying to figure out how what the bed way to make sense of synesthesia is and then finally before we move on from this topic we've got to mention sensory substitution which is a very interesting phenomenon and I remember first hearing about this work as an undergraduate I happened to take a class on the philosophy of mind and in that class there is a student who reported to the class that the work of his uncle was doing this weird stuff and turns out that the student was related to paul bach-y-rita and that he was at the very early stages of doing his tactile visual sensory substitution work and so this has now been around for a while and his cat is getting some more broad attention but it's a extremely fascinating body of work which we are not going to be able to do justice to in the next few minutes that we spend discussing it but it we can at least bring it up and point to the interesting challenges that it raises so bach-y-rita wanted to try to figure out a way to help blind people see their environment or navigate the environment using visual information in some way and he thought well if you get some people who you know their visual cortex is relatively intact but they just have some kind of problem with the eye then it's only there was some way that you could get a camera and get the information that the camera is able to capture like a video camera and somehow allow the person to use that information I mean you know ideally you would like to hook the camera into the input that the eyes were giving the brain but that's that can't be done so we said well how else can we do this and one very interesting idea that he came up with is that you might be able to do it substituting the sense of touch as a channel for the information so the way that you do this is you make something that taps like literally it's a little bar that taps like a telegraph machine so that it goes and one way but one very simple way to illustrate this is that you could have this thing tap you hook it up to a camera and it might the speed at which it taps might vary with you know how far an object is so let's say an object is five feet away it might tap once every fifth of a second or something like that and that if the object we're getting closer it might speed up and tap more quickly and if it got really quick so you can you could see that this thing would do that and then what's interesting is you take this you hook it up to a camera and then you put a device on a person so that they can feel this tapping and usually they have an array of these little tappers so that there's a group of them and there can be a whole bunch of them so you can get complex tapping patterns so you can get different levels of information being related and what's interesting is these people they say at first that they just feel tapping but eventually as they wear this device and get used to using it eventually they sort of the tapping goes away they say and they come to be able to judge how far away things are and what they've been able to show that these people can hit baseballs they can like you put something in their environment able to reach out to it and grab it so and they also describe that it's kind of like a visual experience that they have sensations of motion that they can kind of have the sense of movement and of course there's nothing like the visual experience that we have but the amazing thing here is that visual information and visual experiences to some extent are being created using purely tactile sense sensory input so this kind of challenges some people think this challenges the idea that visual that vision only occurs by the eyes or in other words that there's an organ that vision occurs too and some people say no look it's not the eye that sees it's the brain that's doing the scene the brain needs the information you get it to it from any channel right you could get it in through the auditory Channel get it in through tapping the brain is going to use that to see and generate visual experience so some people will say okay so the whole idea that you have to have a specific sense Oregon which is only able to pick up a certain kind of property which then therefore is only able to be perceived in that way is challenged by these kinds of sensory substitution cases now of course there are people who deny that the point is that there's some interesting questions here which aren't resolved and this technology you know is getting better but it's still in its beginning stages and I encourage you to go on YouTube and to look at some of these they have videos of people using these machines to navigate and recently in Scotland they had a big conference on this and they had researchers put on some of these devices and try to actually feel around and see what it felt like so this is very new exciting stuff and it's challenging our traditional conceptions of what it means to have a sense to be sense to be sensing or to be in related to perceptible properties very interesting stuff okay so all of that was just about humans how many senses to humans have and you might think well gee what about our the rest of the world how many senses are there at all now Aristotle would have said that animals have all animals have these five basic senses in some combination or other but what we have discovered is that there are other kinds of senses that animals have and one of the most interesting is that there are certain kinds of animals that have an electromagnet electromagnetism sense and there are kind of two variations on this that's that's very interesting so one is you find a kind of certain kinds of fish that have receptors that are sensitive to magnetic fields and so that's what's called passive reception they just have this receptor and that tells them when they're in a magnetic field and they can use that kind of information in this sense properties of the field but then there's a kind of another variation on that which is when these animals produce their own magnetic fields and use that as a way to tell where like north is or to navigate in their local environment so that's very interesting there does seem to be more senses in nature than merely the ones that we're capable of having and in fact it turns out that you know infrared perception is not science fiction although maybe it is in the way the predator depicts it but snakes at least have infrared perception and we know that you know there are other kinds of senses out there now once you have this in mind one natural question emerges which is well gee if there are these other senses that animals have like for instance the electromagnetic sense well can I have that sense I want it I want to I want to experience what it's like to sense an electromagnetic field is that possible or is that not possible well some people think it is possible that we are able to extend our sensory capacities in this way and there are some people who will have a magnet a small magnet implanted underneath their skin and the magnet will cause a kind of vibrating or sensation whenever one is in a magnetic field and so people are then a sensitive to a magnetic field in their environment and you can go again go online people will talk about this and talk about what it's like for them and so you might say well look okay is that like the tapping are you now coming so it might be you know you're picking up on pressure or vibration or something in your finger but eventually they say they just don't even feel that anymore and they just are sensing the magnetic field is that what's going on here if so we could extend our sensory capabilities maybe can we hook up infrared lenses to our eyes can if we implant infrared goggles that extend our senses to include infrared these are interesting questions which were just beginning to grapple with now here's where this question gets super interesting because there are some people and there's a group of transhumanists who started a company called grindhouse wetware and involved in has gotten tim cannon and tim cannon has a very interesting and bizarre idea so one of his ideas is that you could if you could connect a tiny microchip to the magnet implanted in your skin and if the microchip were connected to the Internet and could transmit wirelessly then you could have it track any kind of data you want basically and in a sense come to become sensitive to that kind of data so what does that mean here's a quick example suppose you had this set up magnets implanted suppose you have the microchip the microchip is connected to the u.s. crime database so when you're walking around the magnet it's sort of using GPS and the microchip is using GPS to know where you are and it's tracking the crime statistics in the neighborhood you're in and let's say you're getting a buzz of vibration and electrical pulse every time this information increases or decreases so if you go into a neighborhood with a high crime rate you might get a buzzing buzz buzz buzz buzz buzz buzz buzz and if you're in a neighborhood where there's a low crime rate and not a lot of crimes are reported you might almost have no buzzing so are you then becoming sensitive to crime rates are you perceiving the crime rate in an area through this buzzing technique well Tim cannon says yeah he says yeah that's right now you've extended your perception to include perception of things like crime rate he thinks that this we'll be good for society because if you're walking around in a certain neighborhood if it looks rundown and you're not getting a buzz you'll feel confident huh well I'm not going to be scared just because this person in a hoodies walking by me there's low crime rate in this area I'm not getting a buzz so of course you walk in the neighborhood and you're getting high buzz and you see someone in a hoodie you might react differently so this is a way of connecting us to other kinds of properties or so says Tim cannon so I think it's an interesting question whether you get whether you count as perceiving these kinds of properties in this way and this is going to this is obviously related to the question we're going to come back to in the next week and the week after that which is what exactly how high level up can you go property wise and still count is doing perception rather than thinking so some people think look you might be able to perceive colors and shapes and sounds and it's a question about whether they fuse together or stay separate and that's all very interesting but once you go up to things like crime and so forth and so on you're in the realm of concepts and that's not perception anymore that's something else so we're going to look at that but here I'm kind of just flagging it in a in a more abstract kind of way we're going to talk in the next section about whether you can perceive you know elm trees as opposed to merely a certain arrangement of shapes which you then used to infer that it's a nil tree so we're going to come back to those kinds of questions when we discuss the relation between thought concepts and perception under the rubric of consciousness or category of consciousness okay so we're almost done talking about the senses but all of this brings up a very interesting question which I think Fiona McPherson does a really good job of highlighting and I think that this problem hasn't really been discussed as much as it should be so want to end this half of the lecture focusing on it so think about bats we know what bad to do right we everyone talks about bats they emit high-pitched chirping noises and those sounds bounce off their environment and they use that information navigate their environment right they use that sonar we say so how do we describe this case is it the case that these bats have a extra and unique sense like the electromagnet sense magnetic sense they have this new interesting sense called echolocation or do they have the same sense that we have the sense of hearing it's just that their hearing is really good you know like the way that we talk about dogs dogs have smell we say it's the same sense as ours their noses are weird you know their noses are on the outside ours go in but whatever it still smell we say it's just that they have a really good smell so is it like that with bass they just have a really good sense of hearing but not a fundamentally new or different kind of sense like the electromagnetic sense or do we say no they have a weird kind of vision that there's that they see with their ears maybe like the way the sensory substitution people see with tactile stimulation on their sides so which of these three ways do we go there's a question now of course this is going to where we start with next week and it's nice to bring up the bat case here because nagels article what is it like to be a bat sort of drives this home how do we describe what's going on in the bat we can describe a lot of the physiology but what is it like for the bat is it like having this new sense that we've never have a had before such that if we had it we'd be bewildered and confused or is it like having a really good sense of hearing like that you can hear where the objects are or is it like having a really weird kind of vision where you kind of see in sounds or something like that but that's still producing visual experiences well how we answer that question brings us face to face with some of the most fundamental questions about subjectivity and consciousness and our relation to how we know about consciousness so I want to bring that up and kind of go okay wait till next week and we'll get crazy about bats that mania for next week okay so on this same theme I want to bring up two of these other kinds of issues again this is from the Fiona McPherson paper so the two interesting cases are the case of bees and their ultraviolet sense and snakes and their infrared sense so bees are very interesting and one thing we've learned is that they're sensitive to light in the ultraviolet range so we're not sensitive to that and the other thing that we've learned is that this is very useful for bees because it allows them to see where the nectar is in the hunt in the flower so that when they're flying around they can kind of see the nectar but we can't write because the outside of the flower blocks us we don't see ultraviolet so now what do we say again it's a similar kind of question that we just asked what do we say about what's going on here is the bees ultraviolet business kind of like vision but just they see more or is it at a new weird sense the ultraviolent sense I mean in one way they're reacting to the same thing it's light it's just the light that we can't see so how do we say whether it's a new kind of sense or a fancy or different version of one that we already have and the same is true with the snakes they have a receptor that allows them to detect in infrared heat and so forth is that like infrared vision or is it some new infrared sense which doesn't deliver a visual kind of experience so part of the problem here is that one way that we individuate the senses is via what it's like to have the experiences and it's not I mean in addition to the physiology and also anatomy kinds of issues as well as the kinds of properties that are out there and this I think is what's nice about Macpherson's paper is that she ends up concluding look it's a lot of these different things that seem to matter to us when we're talking about what makes a sense of sense and these kinds of consideration show us that well it you're gonna have to do a lot of work if you want to keep it to owns five and if you want to say that these other ones are somehow versions of that so for instance and the snake again what do you say it has infrared vision or this new extra sense okay so we've already talked about this visual substitution stuff but again there's a question about how you individuate the sense of vision and whether this throws a monkey wrench in it alright so that concludes the first half of the lecture which I think really takes up more than half of the time that we're spending here but the philosophy of sensation I think is very interesting it's gotten kind of short shrift and people have talked about perception a lot but there's a renewed interest in the senses and I happen to be one of the people who likes that renewed interest so that's why I'm spending some time on it ok so now we'll turn to some of the more traditional questions in the philosophy of perception and these more traditional questions have tended to revolve around the issue of whether perceptions have content like intentional States do or whether they don't have content so one of these were a way of putting this is the question do are they representational our perceptions representational in the way that thoughts are in other words do they present the world to us in a certain way or do they do something different and here's a different way of asking that very same question in perception are we directly in contact with physical objects or do we ever perceive physical objects so some philosophers have claimed that we never perceive physical objects and that everything we perceive is mental and that's idealism the idea that nothing is physical and that everything is mental and of course we're going to have a whole section on questions about physicalism idealism and those dualism in those various views so we're going to be putting off those kinds of issues we'll be phrasing our question in terms of whether we directly or indirectly perceive physical objects and you might say well look I thought we were putting aside the question of whether there are physical objects out there and so fair enough here's the way that we can formulate the question in perception are we in contact in the first instance with something that's mental or with something that isn't mental now notice that the common-sense view is well no it's not something mental it's the something in the world that physical when you see the the table the table has certain properties and that's not a mental thing that's idealism at the table is a mental thing so many people have thought no no we we have some kind of direct relationship to the physical world the problem the traditional problem is that we seem to be forced towards something which some people have called the veil of perception and we're going to go through this stuff in a lot of detail right now but just to give you the flavor of this the basic idea would be that there is something which stands in between us and the true reality as it is outside of perception like a veil over your eyes so the basic idea here is that there that when you look at the world there's something in between you in the world and that thing is called the mental perception the representation of the world which is in the early days at least likened to a picture that you're watching like an image or light you're sitting inside of a theater watching a film and that film is called your experience and your perceptions and your sensations and your thoughts and all of that is going on in a mental realm which if there is a physical world at all is somehow outside of in what you perceive only indirectly so that's the the basic idea no that's that's all very vague but this problem has been around for a while so maybe familiar with it at least to some extent but let's try to put more of a finer point on this so often you find people espousing a view called direct realism also sometimes called naive realism and really which it's called depends on whether it usually depends on whether the person you're talking to likes it or doesn't like it you can see which one I think is which hopefully so direct realism here's one and people use these terms different ways again I'm not going to be bogged down about word usage but here's one way to use the words so a directory list is someone who thinks that when you look at the table and you see it as having a certain shape and certain colors and so forth that it really is that way that perception directly acquaints you or involves the objects and their properties and one way you can know what they mean is that yes even when you aren't looking at it it's that way so to give an example here suppose you're looking at a red apple and your step it's good light and you're not confused or anything you're looking right at the red apple and you might say ah see I see the apple and its properties that is red and round spherical and if I were to set it on a table and look away from it for a moment and ask myself well is it still there common sense I've said yeah the apples still there is it still a sphere or having that shape that I perceive that it's happening I'd say common senses yeah it's coarse it still has that shape and direct real estate and also it's still red even when you're not looking at it so it just is that way and then when you look at it it's just like you know moving a window to reveal the thing that's there and that's oh another way I like to put this sometimes is that these properties are mind independent so that even if the Apple were in a completely dark room in a pitch-black room with no light at all no people around at all the Apple would still have all of these properties according to the directory list it would still be read and be read in exactly the same way it would still be spherical it'd be spherical in exactly the same way it'd still be an apple of being Apple executives same way the that it the entirety that have the thing that you contact in your experience is indifferent to you or whether you're paying attention to it or perceiving it or interacting with it in any way and of course that's very different than your thought about the Apple like if you think red apples are more delicious than green apples many people are not tempted by the idea that that thought exists even you know on a table when you're not having it when you're not thinking people will say well that thing that's a mental thing you see a thought it only exists when you're thinking so this is a traditional view and you've noticed that we sort of been assuming something like it's easy to talk that way Aristotle definitely has this view he is a direct realistic things what could be more obvious than that when you look at the Apple that the Apple has a certain property the property of being red and that when you experience it that's just you becoming aware of the redness you know don't you creating it and the way you create your thought red is a color which is different from green that's that's something that you create the thought depends on you okay so now why besides common sense what reason would you think that this is true and one thing that many people appeal to here is something called the transparency of experience and this is going to play an important role in our discussion in the next couple of weeks in the next couple of weeks when we talk about consciousness because well people appeal to this idea a lot there so what does it mean to say that experience is transparent in this way well again think about the Apple you're looking right at the Apple you can see it's good light you're awake and you know Descartes says well you know maybe this is a dream and you're not a week so maybe this is a computer simulation and you're in the matrix you don't know that you may have your reasons for believing that that's false and we'll talk about some of those reasons later but but one thing that doesn't seem doubt a bowl or that you have any difficulty in knowing is that the Apple is red and that it appears to you in a certain way now if someone said okay so there's the Apple and you see that is red now where's the experience of the Apple and it being red well if you looking at the Apple and you say okay so here's an apple now where's the experience of the Apple it's hard to do much more than simply sort of point of the Apple hit the thing so some people say look we don't experience the experience itself weeks we have an experience of the object that it's kind of direct in this way we we we directly experience the objects not an experience of the experience and what's interesting is that this version of direct realism what's sometimes called representational ISM and we'll talk about it in the next couple of weeks when we get to theories of consciousness it's it's a way of saying well there's something mental involved a representation of the object but it's what the object represents that you are in contact with and so there's a relationship between it and you and that's the thing that you are aware of not the experience itself the experience itself is not something that you seem to experience so I mean this just puts a kind of formal face on what we've been saying namely that's it common sensical II it doesn't seem like there's something in between you and the world it's not the case in our day-to-day life now we feel as though ah I'm tripping around this thing called my experience trying to get at this other stuff called the physical world so transparency is just a way of putting a name on that it just looks like experience goes directly to the world there's nothing like I go where is it oh there's the experience what's behind it okay so that's the basic idea behind the common sense view and that view has come under attack and the attack really begins with Descartes and it goes through Descartes and Locke and Berkeley and content that traditional modern philosophy is associated with developing a version of this argument and which gives you the velop perception view and but it's not just in modern philosophy if you look you know go and look at contemporary philosophy from the early nineteen hundred's you see people grappling with these same issues and they end up arriving at the same views so the logical positivists and the phenomena list of that time and if you know anything about that they end up saying the same stuff so this is an issue we've got to deal with there are three basic problems or arguments here so one the argument from illusion second is hallucinations in the third is perceptual science so let's look at them briefly in turn so starting with the argument from illusion on the right hand side of your screen there's an actual illusion there so it looks like there is a triangle which is outlined in black and that on top of it is a white triangle outlined in white so do you see that white triangle over there I'm pretty sure you do this a very strong illusion but really all that there are are those three pac-man shapes and the way that the pac-man shapes are arranged produces an illusion as of a second triangle on top of the first triangle so really all there is is like some line segments and these pac-man shapes and somehow the rest is where is it but notice that we said we perceived the triangle but there is no triangle out there to perceive there's no property that we're sensing it's not there it's an illusion the the paper the thing that's on the screen isn't the way that it appears to you so what do you say about that that it seems like there's there's something there it appears to you as though there's this white triangle there's nothing physical which we can say appears that way so it looks like this has got to be something like your visual experience presenting to you something which appears this way which now looks like a hi you have something which is not the thing itself but the visual experience which presents the world as being a certain way even when it isn't because the world is slightly different than the way it is when it's presented excuse me the world is slightly different than the way it actually is when you're looking at an illusion now related to this but different is the argument from hallucination so an illusion is where there is an object there it's just that you perceive it to be different than it really is a hallucination is when there is no object there and you just have the perception so when you when there's an illusion you see something in a way that it's really not and when you hallucinate you there's nothing there that you're seeing you're just having an experience as of seeing or whatever now many people have have thought that excuse me many people have thought that when you have an a hallucination when you hallucinate something you know I tell this story all the time but when I was in college I had lived in the dorms briefly and there was one of these kids in the dorms who took a lot of drugs and he was running down the hallways in his underwear screaming about snuffleupagus claiming to be chasing this hairy mammoth down the hallway and into the bathroom now of course it was just a college kid in his underwear all running down the hallway there was no snuffleupagus there but if you've ever had a hallucination they seemed convincing from the point of view of the Hoos nadir from that person's point of view really appeared to him as though the worse the falafel gets running down the hallway now dreams are not hallucinations but they seem related to hallucinations in that you have a kind of perceptual experience in the absence of anything that your is outside of you that you're perceiving so when you dream about a red apple the red and the dream looks just like the red when you're awake the hallucinating object looked just like the physical object you can't tell the difference now of course you can if you try to grab it you won't feel it and you'll realize maybe it's a hallucination but the point is that there are at least some cases of hallucinations which are completely and totally indistinguishable from the same a current event actually being perceived the reason that that's a problem for the direct realist view is that there is no physical object there which plausibly counts as the thing which you're perceiving so you might say oh you see well the illusion case that's different there's actually a thing there it's just that you know you're misrepresenting it you're misinterpreting a property to it but here in the whose a nation case there's no thing right when you're dreaming there's no object that you're pointing at if you were to point out a red apple and say that Apple looks delicious it's a dream Apple there's no now your point you're having the experience as up pointing at the thing what you're experiencing as of being an apple but that's all at the level of a mental thing there's no physical thing there now you either have to say one of two things either you're always aware of mental objects only because the dream Lamborghini looks just like the real Lamborghini so if they're the same I assume you don't have a I assume you don't have a Lamborghini in your dream so you either have to say well they're the same all the time or you have to say well look there's a difference here that when you actually see the Lamborghini you're you know right there with the object but in the other case there's this other thing they're an experience or mental thing that's called disjunctive ISM if the case anyone cares the problem with with this view is that it's hard to say how it is that from your point of view the two things are indistinguishable and yet different so the red in the dream and the red seen while awake completely indistinguishable so how could they be different now some people will challenge the idea that they are really completely indistinguishable and of course that's something that we can have a debate is there anything dreamy about dream red is there anything in the dream which would clue you into the fact that it's a dream red versus a real red well the movie Inception seems to present us a case where that doesn't happen I mean if you're careful the person in the dream never notices that it's a dream does that really happen these are interesting questions now I'm not telling you the answers to these questions but I am suggesting that many people have thought that this pushes you away from direct realism and towards a view of mental representation where there is a thing which has a Content the content is the way it presents the world to you all right and then finally if you don't like dreams and hallucinations and illusions we can consider the argument from perceptual science so our current Sion's into the actual physical basis of perception and sensation have led us to the brain and you may think that's obvious but of course Aristotle thought that the heart was where sensation excuse me where a perception took place and that the sense organs fed into the heart somehow and the brain didn't play a real role for him and of course he was drastically wrong about that but we know the brain is importantly involved and that's good news and bad news because it gives us a way to account for how perception might proceed that it perceives by the activity of these brain areas but on the other hand we've also discovered that well the brain areas are the only thing that are required in order to have the relevant kinds of perceptions or experiences so if you just stick an electrode into someone's brain and stimulate it turn on the electricity you they'll have an experience like you zap them and they go I taste chocolate you zap them and they hear a sound you zap them and they remember their mother's voice so it seems in principle that you could have all of the attributes of waking experience just by directly stimulating the brain and of course that's the kind of case we have in dream and of course that's the premise of the movie The Matrix if all you need is the correct brain stimulations then you can just bypass the physical world and the way the sense organs are connected to it and stimulate the brain directly and you generate all of the same experiences colors shapes sounds tastes so how then is it that we can claim that in experience were directly and immediately in contact with a physical world if we know that you could put a person in a lab and stimulate the brain the right way in fact it seems like we could stick a person's brain into a vats and stimulate that in the right way and get all the right experience this doesn't that show us that we are in a sense brains in the VAT the VAT being our skull well some people think yes now you might say well look what about pain and so forth don't you need a body for that right yes you have a pain I see the the colour well here is where people often appeal to phenomenon like phantom limb pain and this is something a day card did in fact appeal to in the meditations and other places this is something that Descartes did in fact appeal to in his own writing so phantom limb pain is a very real phenomenon whereby there are people who are missing limbs but who nonetheless say sincerely and we believe trust worthily they say they're in pain in the limb which is missing so we have a case of a person who's missing their arm but yet who claims that the arm hurts they may say you know it's right here in between my second and third knuckle I feel an intense pain but of course there is no knuckle the arms gone amputated now what are we supposed to make of this kind of case well many people will claim that what we make of it is that what a pain really is is a mental thing not a physical thing if you can have the experience of pain and experience it as being located on your arm when in fact your arm has been amputated then that suggests that the experience of pain is not actually located in the arm but rather that you are perceiving something mental the pain and that that pain represents itself as being located on a particular bodily part and this kind of argument which I've just been discussing has led many people to think that perception is intentional in the way that thoughts are or at least to some degree it's more like that than not and the reason that is is because of these kinds of cases when I perceive something I represent the world as being a certain way as having read out there now if these kinds of dream cases and and so forth are correct then what's really going on is when you are perceiving read you are in a mental state which represents the world as being a certain way so that you are not in direct contact with the object in a way that doesn't involve a representation but there always is a mental thing some purely mental thing it goes beyond the properties which you are perceiving in the act of perception and that that act has content and those contents are involved with the way the world would have to be in order to make your perception accurate so when you perceiving read you represent the world as being a certain way and if your perception is accurate and red is out there it's it's represented in the excuse me it's the is the way it is represented when when you have a correct or accurate perception and when you hallucinate red when you're dreaming about red your perception doesn't represent the world accurately so that's what we would call a call a perception which was in accurate and once you have this notion in hand the notion of accuracy or in accuracy which is tied to the notion of a content tied to the notion of representation of presenting the world in a certain way then you have intentionality then you have directedness something standing for something else so in experience we seem to be directed to the world so that even now appreciate this point even if you are hallucinating the experience of red that you're having is presented as being outside of your mind even in the hallucination even in the dream that's why it's often the case that you don't realize you're dreaming when you are or that you're hallucinating when you are and that's because the experience that you're having is presented to you not as though it's going on in your own mind but as though it's coming from outside that's intentionality that's directedness that's representation that's about nasai is it's like it's almost like the senses are telling you and that perception is receiving the information there's red out there it's not like having a sentence or you know will wonder later in the next section whether it's like having a sentence but it's like having something which can be assessed for accuracy read out there and then we can look at the Cantus situation and say yes they're right there is red out there or we can say they're wrong no there isn't red out there so in some sense or other now you may disagree and I'm happy to entertain this discussion but the claim is that in some sense or other the best way to make sense of all of these things that we've been talking about is to attribute intentionality to perception to attribute contents to perception and to attribute accuracy conditions to perception now the next question which we'll talk about next week again is where's consciousness here because all of these things like paradigm examples of conscious experience and also how our concepts related to all this stuff our sensations non-conceptual our perceptions conceptual our perceptual nor thought like are they less not like theirs what role does thoughts play in all of this stuff so now that we've got our two kind of categories thought and perception now we can say aha where do we stand in relation to our price trophy here consciousness and I look forward to having that discussion next week thank you

Channel: Richard Brown

Views: 12,347

Rating: 4.8800001 out of 5

Keywords: mind, consciousness, sensation, perception, synesthesia, vision, gustation, Brain, audition, Philosophy Of Mind (Idea), philosophy of perception, Philosophy (Field Of Study)

Id: 3HIj78ckAK4

Length: 84min 15sec (5055 seconds)

Published: Sat Mar 15 2014