hi welcome back let's do some chapter three as we move on a little bit here we've moved we're moving past the uh the Greek uh era here that we're still sticking into the time of some old ER philosophy one of the things that we might want to kind of keep in mind is is to understand uh where philosophy went geographically speaking and how that's tied to certain aspects of of societal stuff so you know to be a philosopher is a little bit of a luxury especially in ancient times right that uh you could make a living um studying and exploring knowledge and teaching that to others um rather than having to farm and and take and you know fend for yourself so to speak in that way and that required to some degree some degree of centralized uh wealth and and um to to subsidize that kind of of academic Pursuit and so in the Golden Age of Greece it kind of made some sense that with the accumulated wealth in that society that they were able to support those kinds of of activities and the same goes for the uh Roman Empire and then uh as we look kind of towards the and so here we have some some Roman uh philosophy there's not a lot of Roman philosophy really but there's some here and then we have [Music] um after the fall of the Roman Empire what what we see is a little change in philosophy because what's happening is that um the philosophies that we've been talking about here especially in chapter two which are associated uh pretty heavily with Plato uh as we see get bound up into early Catholic theology and so philosophy survives at least in the west uh as Catholicism spreads throughout Europe and so as the monasteries are created the monks can devote their time to philosophy and Theology and and so the the platonic philosophies that we have covered seem to be fairly easily uh integrated into this early Catholic theology and it survives in this way at least for several hundred years until Aristotle is rediscovered in the west as we're also going to see Aristotle's philosophy um was largely forgotten in the west and but was preserved in the Middle East through um of Islamic philosophers and it was after the Crusades that uh Aristotle was rediscovered and that knowledge was brought to the west and it was really Aristotle's influence that sort of um I guess signaled the beginning of something like the Renaissance in European history and and there was a new philosophical movement that that really led to uh the origins of science even uh in uh the the the Renaissance Era of of uh in the early modern era of European history so let's first start though with what happened with platonic philosophy in this uh kind of post-roman to post-roman era here so we have a couple of uh what are what would be considered uh neoplatanist philosophy so neoplatonism refers to new Plato right so so it's it's ha it's when platonic philosophy got uh integrated with early Christian and Catholic theology and that comes from the Roman philosopher platinus as well as Saint Paul who wrote many of the letters included in the Christian New Testament certain themes that we especially see in what we would call Pauline writings would be things like um that the mind and reason and kind of that more uh abstract kind of stuff are associated with things that are good but things associated with the body sensual things uh and keep in mind the word sensual derives from the word senses right so a very kind of typical thing to think of here when we think back to the Greeks and how it was common for them to distrust the senses and think that we don't get anything good from the senses so that's associated with things that are bad and then even with with sin and early uh in early Christianity so we see a real uh connection to the rationalist ideas of Plato right the idea is that the mind and reason that's the true way of getting at knowledge and anything coming from the body or from the senses is not going to tell us anything about what's true and what's real and what's worthwhile for knowing so again this focus on inner knowledge knowledge from and keep in mind for Plato when we get this word psyche from Plato and it means the mind and that's the root of our field psychology is the study of my from from Plato's term psyche it's Plato also intended this word to eat to mean the soul as well and so that means this inner Knowledge from the soul is our true path of for to wisdom and anything that takes you away from that would be considered false and sinful so so it makes some sense and of course you know with this idea from Plato that the soul comes from the Ethereal realm it's it's pretty reconcilable to the Christian idea of the Soul coming from heaven so you can see how kind of easy it was for for the early uh Christian thinkers to be influenced to buy in this kind of platonic thinking so let's take uh one quick look at what platinus was talking about here so it's consistent with this idea that the soul uh and spirituality is is the true form of reality the true form of knowledge he creates a hierarchy and so again the the top of the hierarchy is more of a spiritual reality and at the bottom is the more physical kind of reality so there's a kind of an implied dualism there too and again Plato was a duelist separating ethereal reality from physical reality so latinus puts uh God at the top of the hierarchy so you have the one note the capital O there and it's that's the term that that platinus was using and it's a little reminiscent perhaps even a parminities with the idea of the universe being this eternal spherical one right the singular one and then God at the top of the hierarchy according to patinus creates the universe by emanations so emanations here refer to the emanating Spirit um and that from these emanations is first created closest to God is the the human mind which is the soul or psyche again for Plato and what happens here according to platinus is that we can either turn our minds inward toward the spirit and that inner knowledge or we can turn away from that in an almost literal way turning away from that to then uh see physical reality so the idea here is that we create in a way the physical world as a product of our own minds is a product of our own senses by paying too much attention to the senses we are attending more to a physical world kind of turning our backs on that internal spirituality so in something that's very reminiscent of Plato the idea is that we should rather turn inwards turn within ourselves to focus more on the inner Spirit rather than on the external physical sensory created reality even though I did say that there's a hint of dualism here I think one way to think of platinus is that this is perhaps a properly seen as idealism because really everything is Created from the Mind whether it's the mind of God or whether it's the mind of humans it's it's still created within the mind everything depends on the presence of a mind in some way so in that case we would call this uh idealism so if we think back to our mind body distinctions we've talked about the fact that you could be a dualist and you have both mind mental things and body or physical things as two separate independent realities but with monism there's really just the one reality and you can be a physicalist or a materialist like Democritus with his atoms right or you can be an idealist and say Well only the mind is real and the physical reality is very much just the thing that something that does not exist independent of mind but depends on mind you have to have mind in order for any other reality to exist and so we would really call that idealism to say that ideas in the mind are the real Ultimate true basis of reality foreign so as I had mentioned uh Aristotle and the rediscovery of Aristotle triggers a new movement in uh European history that we call scholasticism in philosophy uh so so first the idea of course is that Aristotle's knowledge had been preserved in Islamic cultures through philosophers such as avicenna so Avis Center was very much influenced by Aristotle so we see uh just as Aristotle had talked about uh being born a blank slate with no innate knowledge and that knowledge begins with uh sensory knowledge begins with experience and then through induction so remember again from chapter two the difference between induction associated with empiricism and deduction associated with rationalism Addison is talking about knowledge that is acquired inductively so we start as a blank slate we acquire experiences and then we do something with those experiences to create knowledge inside of ourselves and it's kind of a bottom-up approach to knowledge so again that distinction uh if you're familiar with modern cognitive psychological terms bottom-up processing is is associated with empiricism top-down process I guess more rationalist idea so havasina gives us one of our very first cognitive psychological theories so just like we have seen uh probably our first psychology theory was a perceptual Theory coming from Democritus which was a theory about how knowledge works so again I think I emphasized in chapter two that it's not a coincidence that empiricists are giving us psychological theories and in that case democritis gave us a perceptual Theory there's a little bit on in the in the book we didn't talk about it much in the lecture from Aristotle about learning uh the laws of Association and next we get avicenna who talks more about uh kind of a stage-like theory of cognition that in many ways is is reminiscent it's fairly similar to Modern cognitive psychology Theory so the first stage we have here we take in sensory information and we integrate that into what he calls the common sense that's a that's perhaps a misleading term because when we use the word common sense now we mean something pretty different uh than what abacina meant we think of just the everyday kind of knowledge social knowledge knowledge that we share with other people so that we're able to kind of communicate in Iraq successfully with others right that's common sense but that means common in the sense that we all know it uh here Common Sense refers to the idea that if we think about you have at least your five senses we'll go with that for now right we have your eyes your ears your skin for touch taste and smell right so his vision hearing touch taste and smell each one of those would be an individual sensory system but when we experience the world we don't experience those five senses independently of each other we experience them uh in an integrated way right you see something and you touch it and it becomes just a singular object here I can hold an object in my hand like this pen and I can see it and touch it at the same time and it becomes a singular object and that's because the touch experience and the visual experience have become integrated in common with each other and that's what we mean here by the common sense is that all of our sensory inputs are integrated into a single common perceptual hole or perceptual representation of an odd of an object that we that we are experiencing in any given moment so that becomes the common sense and therefore that becomes what we are aware of at the current moment so we might equate this to something like attention or perhaps uh working memory but that also takes us to The Next Step as well because then we have what he calls the retentive imagination here imagination does not mean fantasizing like we sometimes think of imagination now but it really literally just means mental images all right hence the word imagination refers to this internal mental imagery so here the idea of course is that you could take an object like this pen and you can perceive it in in many different ways and now you have a perceptual image of it right and even when the pin is no longer visible you can still have an image of it right so you have your your mental representation or mental imagery and that's what abacena means by imagination and so the retentive imagination is essentially this perceptual imagery that we have that we are retaining in our mind at any given current moment so this is very similar to what we nowadays call short-term memory or working memory right what the current content of your consciousness we can now do things with that knowledge we can associate it with other ideas and that's also a job of working memory in modern psychology but here we see that what abacina is doing is he's talking also about learning and he's he's also then drawing on Aristotle's laws of Association the law of contiguity that two things that occur at the same time will be associated with each other and so he's we're composing new ideas and that's why it's called the compositive imagination because we can create new thoughts new ideas and New Concepts by connecting and associating one idea to another idea we also have the ability to judge ideas we can judge things as good and bad and true and false and so forth and he calls this the estimative power of our minds and to an extent we see without abacena here that he believes that this is at least in part an innate ability that our knowledge of good and bad for example and right and wrong he would consider to be innate and uh because this morality is an important part of uh the the innate part of things that uh abacinda thinks that we should have and then interestingly enough he says that we can take all of this knowledge all of our perceptual experiences and all of the the uh connections and associations and things that we've learned and all of our judgments about things and we can remember it all we can store it in our long-term memory so just like we now have a long-term memory idea in cognitive psychology vicena also has basically the exact same idea so we see here ideas that kind of mirror the if you know the three-stage theory of memory and cognitive psychology that there's a sensory memory and then a short-term memory and then a long-term memory we something we see something a lot like that here right the sensory information and the common sense it's like the sensory memory and attention and then retentive imagination is like short-term memory compositive imagination is working memory and learning and long-term memory is long-term memory and so as as uh Aristotle's ideas became uh to to come back to European philosophers and they rediscovered this and they start to to kind of expand beyond the old platonic ways of thinking and as I had mentioned we start to see the origins of science coming along and it's going to come from Galileo for the most part it's going to be one of the key figures in the uh kind of rediscovery of scientific approaches to things in in European history and it begins with this philosophical problem that we touched on mostly in chapter one just a little bit in chapter two about whether the universals are real or not so you know the whole issue of what makes a dog a dog right and we can think about the fact that maybe there's something that makes a dog a dog in the terms in the terms of some Essence that a dog has right so it has some Essence some essential property that defines it as being a dog or back to the question of a perfect circle right we talk about these things as well I've never seen a perfect circle so where does the idea of circularity come from I have the idea of circularity in my mind where does it come from that's a that's an epistemological question is it learned or is it innate right that's the epistemological side of empiricism versus rationalism but separately is the question of whether or not it is even real in the first place and and that's a question for science and to some extent because when we study things scientifically we want to know am I studying reality right am I sometimes we have to study things in science that we can't actually directly observe in some way right physicists for example study atoms and subatomic particles no one can actually in any direct immediate way perceive a a boson right like the Higgs boson that was a big deal in science in physics a few years ago but rather what happens is that we do uh experiments and we record some things and we get a lot of data and we look for patterns in the data and the physicists came to a statistical conclusion that there are patterns of the data were consistent with what would be expected by the presence of a Higgs boson but nevertheless all the Higgs boson is in any given person's mind is nothing but a an idea a mathematical abstraction that that uh was inferred based on the mathematics and was then confirmed based on statistical analysis of some observations in particle collider experiments but we've never seen one so just like we've never seen a perfect circle we could ask is it real does it exist and like just as we've never seen the Higgs boson we could also then ask is it real or is it just a mathematical abstraction and in Psychology this becomes a particularly important issue because I have never seen in another person at least a mind I have my own mental experiences my own ideas and thoughts and feelings but I can't really see the minds of others so I could also be left with the question of is the mind of another person even real uh or you know so again I can I can study behavior and I can infer some things about the human mind based on my observation of behaviors in other people but again that begins the question is it real or not so that's the real issue here and the problem of universals we have all these Concepts we have all these abstractions Perfection Infinity essential things like the essence of dogness or the essence of circularity uh or ideas in the mind at all and uh whether they correspond to anything that's real so let's let's have a look well one possibility comes from this guy William overcom so if we remember the the two sides in the problem of universe so our nominalism versus realism right keep that separate from epistemology that's empiricism versus rationalism there are some parallels as we see empiricism and nominalism tend to be connected to each other people who are empiricists also tend to be nominalists but they are not the same thing empiricism means you're born a blank slate nominalism means that these ideas exist as names as much as ideas in the mind and that's all that they are they don't correspond they do not correspond to anything that's real that exists outside of the mind and so William overcom gives us the famous Occam's race or the idea of this uh you know the simple way of thinking of it is just keep it simple eliminate extraneous assumptions and unnecessary assumptions uh it's also defined as I have written it here as do not multiply entities Beyond necessity and what that means is that if you have two entities and you don't need two entities shave one off that's why it's called the razor as we shave off extraneous assumptions or extraneous entities what do we mean by an entity here well in the case of talking about ideas in the mind such as the idea of perfect circularity that's one entity it's a thing right it's an idea it it's it is a thing right so that's one the second entity would be the idea that in order to explain the idea of circularity in my mind I would also have to invoke a real Circle somewhere else outside of the Mind Plato for example said that there is a perfect perfect form of circularity that also exists somewhere else beside the human mind and that exists in an ethereal Realm so in that case we have two entities right we've got the circle in the Ethereal realm and we have the circle in the mind and Plato says that they are both necessary to explain uh our knowledge and what William of a com says we don't we don't need that extra Circle we don't need the one in the Ethereal realm he says that we can we could argue that I could I could just figure out or infer the idea of circularity just through experience by looking at one imperfect Circle and then another imperfect Circle and then another and that over a sufficient number of observations of all kinds of imperfect circles I would get closer and closer to understanding what it is that they all have in common and so I'm extract abstracting out from those experiences the essence of all of those experiences which would be the essence of circularity and from there I would be able to understand circularity uh just based on imperfect experiences without there needing to be any kind of absolute Circle somewhere else such as an ethereal world so in that case the the the perfect circle becomes a a an unnecessary entity so we can take the razor and shave it off and we are left with just ideas in the mind so in that case that's what we're doing here we can say that we we don't we do not doubt that ideas exist in the mind but we don't need any other entity to explain these ideas in the mind we don't need this other external reality right so we can leave ourselves with just the ideas that's nominalism now we might imagine that there's another ISM that we might might maybe start to think about if we really take this to an extreme because does this really mean that we don't need any kind of reality outside of the Mind are we talking about idealism here that that we can just get rid of an external physical reality or any other reality besides just what's going on in our own minds and there's another ISM here called skepticism right skepticism is the idea that I start to become skeptical about any kind of reality whatsoever outside of my own mind and from a scientific perspective we might not like skepticism this means that all of our scientific knowledge doesn't really correspond to anything that's real that physicists are not discovering the true properties of reality they're just really creating abstractions and Mathematics and and and theories that uh all managed to be consistent with each other but don't really correspond to any truth about the universe and of course that's what a universal is it's meant to be a truth about the universe but uh if you're a nominalist we might be led to have the conclusion that there are no truths of the universe and um that's what skepticism is all about is that I remain skeptical about the truth value of any statement that I might make about circles or dogs or people or atoms so maybe we don't like that so we're going to see somebody come along to to try to uh rebut what William of a com is is saying here so so realism would be our alternative so we're going to talk about first Plato again and and so Plato's not the rebuttal to to William of a calm but but we're gonna remember what Plato said Plato was a realist but there's another name for that it's it's technically what Plato's uh philosophy is called is exaggerated realism the reason this is called exaggerated realism is just that it's an extreme version of realism he's saying that for each idea we have in the mind such as the concept of circularity the concept of a dog or a cat or a squirrel that um that there is that there is something that corresponds to that in the Ethereal realm that there is in the Ethereal realm the perfect form of dogness in the perfect form of Katniss and the perfect form of squirrelness in the perfect form of circularity and so there's always two things there always has to be two things right it's there's always the idea and there's always the essence or form in the Ethereal realm and those Essences or forms get to exist all by themselves and they're independent of everything else they just get to have their own absolute existence all by themselves in that special Realm so that form of of assigning a a true total independent reality to the Essences or forms that's why it's called exaggerated realism because these forms get to maintain their own independent reality there what we end up here in this reaction against uh William of a common Occam's razor is what's called moderate realism moderate realism comes from Saint Thomas Aquinas so he says that he's going to be a realist and so hence why it's called realism and it's so when we say that we're going to say that the universals exist as things outside of the mind not just as as ideas in the mind like the nominalist ideas but we're calling it moderate realism rather than exaggerated realism and and so what makes it moderate here and what what Aquinas is doing is he's taking the Essences or the forms and he's taking them out of the Ethereal realm and he's putting them into the Physical Realm with the objects themselves so if we go back to this question what is it that makes a dog a dog right we have some trouble with that we we think is it the four legs again remember that for something to be a definitive of an Essence it has to be it has to have this quality of if and only if right a dog is a dog if and only if it has four legs so so that means that if an animal has four legs it's a dog and not anything else and we know that that's not true because cats have four legs zebras have four legs elephants have four legs so that's not a characteristic that narrows everything down to a dog and of course if a dog were to have for some reason only three legs it would still be a dog losing the leg doesn't um you know take away its essence of being a dog right the same goes for having a tail or a fur coat or a snout or anything like that right so there's all these characteristics that might be something that a single dog will possess but it's not a universal right it's not something that every dog necessarily possesses at least not in the same way so if you're if you're William of a calm you would just say well dogness is a it's just a a name it's an idea it's a category you've seen a Great Dane you've seen a poodle you've seen a Chihuahua you've seen a German Shepherd you've seen all these different breeds of dogs they're all very different from each other but over time you've been told that this is a dog and that's a dog and this is a dog so you create through experience a your own mental category a label a word that you learn to apply we do this as young children when we learn the names for things and we see that children will do things like make category errors sometimes they will they will learn the word dog and then maybe for the first time in their life they'll see a cat and they will say oh this that must be a dog too so they'll call it a dog and until they're corrected by their parents who say no no that's a cat and I was like oh okay so now there's two different kinds of things that have four legs and a fur coat and a tail and so forth and that one's a cat and this one's a dog and they have to figure out where these category boundaries are but over time they learn to do that so that they will correctly identify all the various things that we call dog as a dog and all the various things that we call cat as a cat but as far as anomalist like a comma is concerned we are just putting these categories uh together in our minds we are just forming associations and links between them in our minds and we're giving them names and that's all that that is is it's it's just the culmination of human knowledge and we we give a name to it hence the why it's called nominalism Nam means name and we share that with other people so that we can all now agree that we're all going to call this group or this category of things by the same name um but that's all that it is it's what we would call a linguistic construct or maybe a social construct right we socially using language agree that this is a category but it could if you're anomalist it's a category that's completely arbitrary and invented by the human mind it's not real in the sense that it has some absolute reality that is separate from our own human knowledge but if you're going to be a realist like Thomas Aquinas then the answer is no no there must be something about a dog that defines it as being a dog and his simple argument for that if we call this simple at all is simply just to say that if this thing must is is if this thing does not have an essence of being a dog we would not be able to recognize as a doc his argument is that even as children when we are learning that all of these different animals have something in common that make them recognizable as dogs so that we can actually learn the category and correctly call them dogs when they're dogs and call them something else when they are not dogs um that there's actually some Essence that we're learning that we're picking up and even if we can't really verbalize What that particular Essence is it nevertheless must be something that's real something that's really in the dog and part of the dog otherwise it would not be recognizable as such so Aquinas is basically saying that yes all of these animals have have a lot of unique character characteristics what we what he calls particular characteristics right their their size their shape their color their hair texture the shape of their snout the length of their tail the way that they move the way that they bark will all be particular that is distinct and unique to each breed but nevertheless there must also be something that would be we would call an essential quality right so every object and this is the crucial part of Thomas Aquinas here every object so underline this let me say it again every object has both an essential quality that defines what it is and a particular quality that makes it unique from other individuals okay just like humans right every human has particular qualities that Define Us in terms of our individuality and uniqueness but we all have an essential quality that defines our Humanity and aquinas's argument here is that you cannot reject either of these two things they have to be bound together they have to be interdependent with one another an object without a particular quality would just be an abstraction and that can't be a real thing then that's what Plato was talking about essentially is that the the forms or the Essences in the Ethereal realm are pure Essence without particular qualities and it's just an abstraction and that can't be a a real thing so so that's that's why Aquinas doesn't like that but he says that anything that contains only particular qualities without an Essence would not even be a thing either because it wouldn't be recognizable right it wouldn't be you wouldn't be able to recognize it as part of a group as sharing anything in common with anything else so in that case any object has any recognizable object has to have both essential and particular qualities or it would not be an object at all so with that statement we get aquinas's moderate realism everything has to have as I have also written here both the Central and particular qualities and these two two kinds of qualities are interdependent right you cannot have one without the other ask again I have repeated this here anything with particular qualities but no essential qualities would just not be able to exist because it would just not be recognizable it would not have an identity but likewise the converse of that is anything with with essential qualities but no particular qualities would just be pure abstraction and that would also not be uh something that could exist either so now that we have that let's tackle a different kind of question so we've been talking about things like circularity dogs and cats and all this sort of things let's talk about other kinds of things that we recognize because this particular example is one that has um confounded psychologists for a long period of time and even philosophers too color what makes something blue blue and and so we could think oh surely it must have something to do with the wavelength of light right um but we can also realize that there's lots of different wavelengths of light that we all perceive as being blue yet they are in fact different wavelengths right so this is an example of what's called categorical perception which we have already been talking about perceiving dogs even though they're all different in some way are still seen as members of the same category so that's categorical perception circles again at some point a circle is allowed to have some imperfection and it still is seen as part of the category of things called circles but beyond some threshold we would might start perceiving it as something else such as maybe being an oval right so what about color what are the what is what are the thresholds what are the category boundaries for color what makes something blue is distinct from something that's green or red you know all these different shades of blue you've got sky blue you have navy blue you have uh aquamarine you have nice royal blue what is it that all those things have in common and what is it that they have that something that's red does not have it's really hard right and if we think about the the actual physics of light we talk about the wavelengths of light we're just thinking in terms of you know a spectrum a continuous spectrum of wavelengths here you know you go from 400 some nanometers to to 475 some nanometers and it's all blue and then all of a sudden you go another five nanometers longer with the wavelength and it becomes green and and uh what changed it was just an extra five nanometers in the length of the wavelength of light and suddenly that becomes something completely different there was no physical you know crucial physical uh change in the wavelength right the difference between 440 versus 450 nanometers 10 nanometer difference leads to no category change but somehow the difference between 470 and 480 nanometers leads to a category change why is there a boundary there that leads from from Blue to Blue in one at one point but then blue to green at another point and less perhaps that that boundary is something that's created purely within our own minds right something about the the way our our visual receptors respond to the light and the way in which our brains respond to the different wavelengths and create the category internally and if we do that we would need to realize that we have taken ourselves right back to nominalism right that that blue is not an in fact a property of the object that we are looking at and neither is green or red or yellow or orange it is merely a function of our psychological response which is a function of the way in which our visual systems work and so we have now taken anomalous approach to that but nevertheless that since we don't like nominalism we don't like skepticism right um we might attempt to take a moderate realist approach to color so we would say that okay yes all blue things must possess some essential quality that makes them blue but then also have particular qualities that defines a particular shade of blue that they are but this seems to be somewhat unsatisfactory we don't we don't like the the implied nominalism of the ideas uh and and moderate realism just seems to say well okay sure there must be some essential quality but we you know what is it exactly so this is where Galileo comes in and Galileo is attempting to to give us a way in which we could actually not be skeptical right that we could actually say it is possible for us to to scientifically study some things about reality even if our senses do not always exactly match reality so Galileo gives us a distinction that he talks about here is the difference between primary qualities and secondary qualities so primary equalities describes the way objects exist and this means that this means they have properties that we don't necessarily perceive and then secondary qualities corresponds to the way in which we perceive them which may not be identical to the properties that the objects actually have so if we think about color as our example we would say that color is a secondary quality right it exists in the mind and it is a function as we know now as Galileo did not know but as we know now is a function of things such as the way our visual systems work the particular kinds of uh cones that we have but at the same time it is not completely arbitrary our our response to to these objects they are visual response because the objects in the world have another property that we could call reflectance right they they when when you shine light on an object it will absorb some of those wavelengths and it reflects other wavelengths and the particular way in which it absorbs and reflects wavelengths has a very important relationship to the color that we see so even though color is not a property of the object it's a property of of the mind and that makes it a secondary quality it still can be connected to the object right even though it's not the same so there is a dualism here I hope that you see right that what's happening in the mind can be connected to objects in the world but it is not the same so the objects have primary qualities they have their real physical qualities and then in the mind we have our experiences of those qualities which are not the same even though they might be related in ways right Galileo really didn't spend a lot of time talking about um color he was really interested in motion because as you know as an astronomer he was interested in planetary motion and he was studying the the paths of the stars and other and other planets of the solar system and the Earth around the Sun and all that and even on Earth he was studying motion he studied uh um the projectile motion and he would note for example that if you follow the trajectory of a of a cannonball it it very closely mirrors the path of a parabola in space right and we have a mathematical equation that describes the trajectory of a parabola but one of the things that Galileo noted is that the actual trajectory of a cannonball didn't perfectly follow the parabolic trajectory but it approximated it was close so again the argument is that what what Galileo is saying here is that there's the difference there between the primary and the secondary quality that the parabolic trajectory represents kind of like what it was really doing and the secondary quality represents the way we can experience it which is somehow less than perfect maybe there's a little reminiscence uh to Plato here as well that distinction between kind of a Perfection behind the scenes and reality right but we can't see it so here's an example of breaking that down so we can talk about you know the second Point here motion actual Motion versus perceived motion is kind of like Galileo is getting at there with this talk of parabolism projectile motion but the third one right color right so on the left hand side we have the primary quality reflectance objects just reflect light but in the mind that becomes color the same could be applied to the fourth one down right sound and vibration so a vibration uh you know is is really just the idea that sound is a wave right when two things Collide up clap your hands right what happens when I clap my hands is that I'm compressing the air between them and then I create a vibration that travels through the air an air pressure wave uh that that is traveling through the air and it eventually enters into your ear which vibrates the eardrum if you know your basic urine atomy it vibrates the eardrum and then behind the ear you have those three bones the hammer ambulance Stirrup so again each one of those three bones vibrates that vibratory wave travels into the cochlea of the inner ear and it causes a vibration of the basilar membrane embedded within the basal of membrane you have hair cells your your actual auditory neurons so those vibrate as well and then of course that causes a vibratory pattern in the auditory nerve which then is transmitted to the midbrain and up into the brain so now you have a vibratory pattern in the auditory cortex if that's all descriptive in terms of vibratory patterns where does sound come in it's the idea of course is that we're going to jump from vibration at some point this jumps from this physical vibratory pattern into a psychological experience of oh I hear someone clapping their hands right so it became it went from a vibration to a sound and sounds have qualities that are not quite the same as vibrations right that we can describe sound in terms of its loudness or its pitch it's high pitched or low pitched for example but that's not the same as the frequency of vibration or the amplitude of vibration likewise the last one down here your sense of taste and smell is a function of the chemical composition of something we could say that something is like citric acid for example just acidic but it tastes sour right so sourness is not the same as acidity acidity is more of a chemical measurement in terms of pH sourness is sourness it's a psychological experience of that quality so primary and secondary qualities are related to each other but they're qualitatively not the same right which also gets us to that old philosophical Chestnut here so we see the dualism right primary and secondary are related but qualitatively not the same That Old Chestnut is if a tree falls in the forest and there's no one there to hear it does it make a sound and well I guess the answer to that question depends on whether you really want to believe what Galileo is talking about here in this kind of dualist idea because if we say that what's happening is the tree we're not denying the tree existed right a tree was there it falls it creates a vibration that travels through the air but unless there is a a listener right so a conscious person or animal in that environment that can detect those uh vibrations with their ears and then have an experience it does never it does not ever become a sound right so unless it can actually jump from a physical vibrant vibratory process to becoming a sound in the mind of someone in that in that environment it is the answer to this question is no right if a tree falls in the forest does it make a sound no but that's based on the Assumption as Galileo has given us that sound and vibrations are not at all the same thing again they are qualitatively distinct from each other keep in mind we don't have to agree we could be a materialist modest right that's where you're only having one kind of reality and now what you're going to say is that the sound is a vibration right there is no separate psychological reality independent of these physical vibrations it's all just physical vibrations that are transmitted from the environment into the brain and it's all a physical process and so in that case your answer to this would be yes that's not what we hear most of the time when we talk about this kind of question it's usually a question that's designed to reinforce dualistic thinking but if you don't want to be a duelist you could say no to that but keep in mind that what Galileo is doing is he's actually trying to find a way in which we could justify the fact that our internal psychological experiences don't seem to match reality but he believes that they're still connected to reality right the idea is that even though the pitch of a sound is not the same thing as a vibration it still has a very important relationship to the vibration because we know that the frequency of the vibration has a pretty specific relationship to our perceived pitch right high frequencies mean higher pitch so even though there's a qualitative distinction there's a quantitative resemblance right that that that that has has the frequency changes pitch changes in systematic ways and so we could find a way of suggesting that okay yes even though they're different from each other maybe there's a mathematical way in which they could still be connected a quantitative mathematical connection between primary and secondary qualities in fact that's going to be one of our first branches of psychology we're not going to get to that until chapter seven but it's called psychophysics right psychophysics is the study of that kind of quantitative mathematical mapping between psychological reactions to physical stimuli right so how does the frequency of a tone affect perception of pitch and is there a mathematical relationship that can be formulated for that and that would be a psychophysical function and that's what we're going to see people trying to do in the earliest days of experimental psychology in the early to mid 1800s we're going to be doing stuff like that it's called psychophysics in fact we still do psychophysics in modern psychology not quite as popular as other areas but nevertheless this is setting us up to get there but we still have lots of other things to talk about before we get to chapter seven that is the end however of chapter three