字幕表 動画を再生する 英語字幕をプリント hello and welcome to this online section of introduction to philosophy this series of videos is recorded for my HUP 101 course a class that I teach at laguardia community college my name is doctor richard brown and i will be the instructor of this course uh... this series of videos is, um, uh, primarily intended for classes uh... my online classes at laguardia colleges as I just mentioned uh... but i've taught this course of for many years i taught it at brooklyn college before i came to laguardia and so uh... these slides these powerpoint slides also accompany the Chaffee book uh...the philosopher's way which is the book that students in this course will be using and so, um uh... these slides then represent what I kind of drew on the board, or whatever a complete course in philosophy and um... in order to do that the first question that we've got to start with just by way of introducing the topic uh...is well, what is philosophy? what is it that we're going to be studying in this series of lectures? and answering this question is very difficult because if you ask a hundred different philosophers what it is they do you're liable to get a hundred different answers um so it's not a very easy question to answer. Different people think of philosophy as different things. now, typically uh... sometimes people conceive of philosophy as asking certain kinds of questions well you know very deep questions about the meaning of life and what's real and those kinds of things and it's true that philosophers do ask those questions and so one way of talking about philosophy is talking about those kinds of questions that philosophers deal with and the kinds of answers that they give and so we'll talk about that at the very end this lecture, talk about the various branches philosophy uh... another way of thinking about philosophy is looking, well, sort of what the word means and how people have thought about it historically and so that's what I want to turn to first uh... i want to actually spend a little bit of time talking about what i call the pre philosophical way of thinking uh... or uh... the way that people thought about reality before philosophy uh... was discovered and there was some characteristic differences in this historical way and so one thing you'll notice uh... in these lectures is that I'm very historically orientated and i think that it's very important for us to put the questions were interested in in this kind of historical perspective so we will be going uh... historically in order all right so to start with then at the beginning let's give a very brief introduction to the origins of society and all of this should be taken with a grain of salt, of course because when we're looking back on history we're doing our best to reconstruct events uh... that uh... only uh... fragmentary evidence of which survives so we must always remember that we're doing the best that we can so we'll be referring to this timeline here over the course of the class and so here I'll mark where we are now the present-day CE and those of you probably know that we used to use 'BC' and 'AD' 'BC' for 'before christ' and 'AD' for 'Anno Domini' which uh... means in latin 'the year of our lord' uh... and year one here is supposed to mark the historical birth of uh... jesus of nazareth not everybody is a christian and so having these christian-centric dates uh...there is a movement away from naming them that way so we changed it to 'CE' for 'common era' and 'BCE' for 'before the common era' and i use those prefixes here suffixes here (whatever) but the turnaround date is still year one there where historically many have thought jesus was actually born. There is some debate about that, as i said earlier, all of this is sort of piecemeal knowledge that we have but there are...some scholars think well maybe he was born slightly earlier than year one or slightly later than year one, by which I mean the actual historical jesus uh... uh... so we're not sure but that's the date that year one is set uh... and that's why it's set at year one now of course there are many cultures that don't have uh... their dating system this way so there are cultures that don't start over when they think that jesus was born and so for them uh... they will number the year not 2011, like us, but five thousand something but so roughly speaking then if this timeline were to extend all the way to the left a good space using this same kind of rough metric that I've had here you'd have to go another seven to 10 thousand years in the past uh... to find human beings as we think of ourselves now settling down uh... so this is the invention of farming you may not think of farming as an invention but it is an invention there are certain technologies which are required in order to farm; you need to be able to irrigate, you need to be able to control water um, by having buckets for instance or uh... irrigation channels, you need to be able to use a hoe planting seeds in nice orderly rows, etc so we have evidence and again none of this is hard and fast um ten thousand roughly or so uh... years before year one people started farming so then for roughly seven thousand years people lived in this way farming, settling down, domesticating animals no longer living hunter-gatherer lifestyles no longer being nomads but nothing like a city developing there are still these tribal associations, it's still very family oriented, extended family and etc but around three thousand five hundred years before year one we find city life as we know it so what we call civilization civilized life developing and cities back then of course would've been much smaller a large city would comprise about a thousand, two thousand people something that we don't consider to be very large but of course the population back then would've been much smaller so there would have been very large cities with a thousand to two thousand people and of course what corresponds with the origins of civilization are the invention of writing and human beings around this time seemed to have developed writing in various places around the world so it's not just in the western world that we find writing, cuneiform tablets, etc, being developed uh... but also of course everyone knows about Egypt and the hieroglyphs and lesser-known perhaps in the americas they were also developing forms of writing and in china and the east as well people are developing writing around this time and it's interesting to look back at some of these earliest kinds of writings...um...they give us some kind evidence of what the people thought at the time and the way they viewed themselves in the in the grander scheme so I want to take a look at that but first i want to focus on the places that we're going to talk about so here's some pictures this is the map of ancient Mesopotamia uh... over on the right over there is where we're going to be focusing on uh... babylon and sumer. Babylon is where the tigris and euphrates rivers meet and those of you uh... who are aware of current...uh... ...um... nations and politics will recognize what is babylon there as modern day Iraq. So, there's Egypt there, the Sinai peninsula and of course the out of africa theory which uh... uh... some scientists think describes the way uh... we human beings evolved has it that human beings evolved in Africa and then migrated nomadically up and across the the peninsula there and then settled down uh... started farming in babylon uh... in areas in Egypt and so on where these cities later developed, and so, uh... what we find from these early areas are actually pieces of writing which are very illustrative so i want to look at one in particular and this is, um... famously known as the Epic of Gilgamesh. Now if you haven't read the Epic of Gilgamesh you probably should it's a great story and it used to be read n English 101 classes, I don't know if they still do or not, or in English 102 or something like that uh... but it's an epic in the sense of an epic adventure and it tells the story of a king named Gligamesh who was a great king of one of these ancient cities and Gilgamesh wants to know why people die, what the meaning of life is and how we can be immortal. So, he really wants to know the answer to this question and he decides that the way he's going to answer it is to go on a journey to where the gods live and to demand of the gods that they tell him, Gilgamesh, the answers to these questions. and so he does. A lot of adventures ensue. uh... and I won't rehash all of the stuff that happens He eventually gets to the gods and asks them this question and they set him a bunch of tasks. They say 'Gilgamesh, if you complete these tasks we'll answer your questions, tell you everything you want to know'. the tasks are very much like the kinds of things you find in greek mythology, um he has to kill a certain beast, he has to climb a certain mountain, he has to divert a certain river uh... and etc. So, he does all of that stuff. and finally he comes to the last task the gods the gods tell Gilgamesh 'you must stay awake for three days and three nights' and if he does this they will tell him the answer So he says 'no problem' but of course he doesn't have red Bull or caffeine or any of the other luxuries, No-Doze, that modern people use to do all nighters so he stays awake for three days and two nights and on the third night he falls asleep. So, poor Gilgamesh wakes up in the morning to see the gods saying, 'oh well, you were so close but now you'll never know.' they just...he does not complete the tasks and he does not get to know the answer he becomes very angry and then he finds out, uh, comes to a realization that the way to be a immortal for a human is to have your name remembered by doing great things. By building a great city, by being a fair ruler and so on an so forth this story, this very brief synopsis, a butchering, of a story uh... illustrates two points that I want to make. So, the first point is that it's sort f wrong to think of philosophy as simply a group of questions because notice the kind of question that Gilgamesh is asking here are very deep questions why do we die? What's the meaning of life? How do we become immortal? What's the right way to live? It is not as though only philosophers are interested in those questions human beings are interested in those kinds of questions That seems to be something that afflicts us in a certain way. We want to know the answer to these questions but of course there are different ways of answering those questions and gilgamesh embodies a particular way of answering those questions Notice he never once entertains the idea that he himself could figure out the answer to these questions on his own. Immediately from the beginning the proposed solution to the problem is to fid out those who know, the gods and to ask them and this is the general theme of the pre philosophical way thinking that human beings are not capable knowing the way the word is...only ...they are like children who can't understand the most simplest things the world is filled with the supernatural personalities who really know. The world of the gods as you might be familiar from uh... retellings of these stories. Zeus, Athena and so on um, that's who controls reality and if you want to know then you've got to ask. Now of course uh... these would have been different gods for Gilgamesh and people like him but the idea that this roughly the same so there's a conception of human beings as supplicants as not being able to know as uh... having to be told by divine revelation the way reality really is now there's another story that illustrates this point as well and this is something that we can see from the Code of Hammurabi. Now, the Code of Hammurabi is famous because it is one of the earliest written laws we have and you can actually go to the website of the Louvre and read a translation of the Code of Hammurabi. It's there on their website. It's extremely interesting i recommend that you do it if you have the opportunity if you do this you'll be struck by two things. So, one is the thing I was mentioning earlier, namely that they're dealing with the same kind of questions that and problems that we deal with so their lives are roughly very similar to our lives. They live in a city. They're around people they don't know and aren't related to and there are various questions of how you ought to interact with them. What obligations they owe to you, what obligations you owe to them and ways of coordinating behavior such that you can discourage certain kinds of behavior and encourage other kinds of behavior. Very ordinary kinds of problems. So, that'll be the first thing you're struck by. Now, of course the way they discouraged behaviors was by a very eye for an eye type of justice and uh... that will be something which is kind of a shock to modern people their system of punishment was very, very, eye for an eye, very brutal I guess we might say but, uh, So, I don't want to dwell on that, that's not really the main point. so the other point is the source of the justification of these laws So, the laws were written on a giant pole ascribed around it which was smack dead in the center of the entering gate of the city that Hammurabi controlled so that any person who walked into the city would be faced first with this inscription of all the laws. So that there was no excuse and everybody knew what the laws were they were right there you could check them. But why should you obey those laws? Who was Hammurabi to tell you these are the right laws? Why these ones as opposed to some other set? or no set at all? Well, the answer is contained in the preamble of the Code of Hammurabi and the answer is roughly this: Hammurabi is the son of god He is the slayer of Tiamat, the great dragon, the orderer of chaos etc, etc, blah, blah, blah he built this, he did that, god is his father, etc, etc, and so who else better to know than Hammurabi? so again we see this appeal to divine intervention divine revelation as the only real way of knowing what these laws are so notice that nowhere in that preamble is there anything like well we've thought about it carefully and these appear to be the best way to achieve the goals that we've set for ourselves uh... Goal One: Coordinated behavior, Goal 2 Commerce, etc so nothing about us discovering the truth but a lot about the truth being revealed by a greater source and that really is what's contrasted with the origin of western philosophy so, now, again, just before we move on I want to take a second to emphasize that, um, I'm talking here about western philosophy and we could tell a different story talking about the origins of eastern philosophy or american philosophy so since we're talking about the sort of society of the west which has its origins in Ancient Greece uh... that's where we're going to be focusing but that's not the say there's anything overly specifically special about the greek people at this time uh... people have been interested in these questions and people around the world have developed answers to them although people n Ancient Greece uh, have one really definitively western ways of dealing with these problems and questions which has influenced uh... the spread of our culture so we'll be taking a look at that so again here's our timeline uh... now there remember farming invented about ten thousand years before year one civilization begins the invention of writing uh... uh... about thirty five hundred years roughly again debatable but roughly around that area uh... before year one and so when does philosophy start? Well we date the origins of western philosophy to about six hundred years before year one notice that's roughly three thousand years from the beginning of writing to the origins of philosophy so during that time period the pre philosophical way of thinking as i have characterized it dominates and we can think right around twelve hundred BCE so that's right around the mark there where it says '1000' uh... was where many scholars think that moses lived and of courses moses gave us the ten commandments and that's prototypical of this pre philosophical way of thinking what's the right way to live your life? Well you can'y answer that question moses goes to mountain, god reveals to him directly the correct rules for living a good life and then moses comes back and says god told me this is the right way to do it so that's the uh... another way of thinking about and of course if you don't do it god intervenes and punishes you So these are kind of the twin ideas of the pre philosophical way of thinking when there's an earthquake god's punishing you for breaking some rule when there's a nice bountiful harvest god's rewarding you for following the rules and so it's important for us to know what the rules are and the way the world works but we can't know for ourselves so we're dependent on somebody else, the gods, handing that down and then them handing that down to us so that's roughly the pre philosophical way of thinking and the philosophical way of thinking begins around six hundred years before year one and i should caution um... just so that there's no misunderstanding it's not as though once philosophy is discovered this older way of thinking goes out of date. People still subscribe to this view and people did at that time as well it's just that this is the earliest that we know of where people start advocating some other way of thinking about human beings and our relation to reality so let's take a look so this is where we're going to be spending uh... roughly one third of the class is spent in ancient greece almost uh... over a third of the class actually so it's good to get familiar with it so just look at the map for second you can see the aegean sea there separating Greece on the left from Ionia on the right 'Ionia' was the ancient name for that land mass nowadays we would call that that's where turkey is uh... buts this is a map of ancient greece so the isle of crete down there at the bottom the Cretans who lived on the Isle of Crete, even in the ancient period had a reputation for being liars aristotle famously wrote that he was perplexed by the sentence 'all cretans are liars' so i don't know what those ancient cretans were up to but uh... they seem to have developed a bad rep so then moving on up you can see uh, Corinth there and Corinth is famous from the letters from the Corinthians and to the Corinthians which are included in the Bible Then up top there's the oracle at delphi and delphi and the oracle will play an important part of the story of the life of socrates and we'll talk about that but you must know the oracle from uh... delphi from other sources uh... more than likely you'd know it as the source of the prophecy uh... that a certain person would mary their mother and killer father and uh... I'll leave you to fill in the name of that famous person but i'm sure you know who I'm talking about uh... ok and then there's athens which is where a lot of the action will take place because there is where socrates and plato and aristotle socrates was an Athenian uh... plato was the student of socrates and starts the Academy there and Aristotle goes to study there so with plato at the academy and then starts his own school and so athens has always been an important part of ancient philosophy but actually the story starts over in Ionia in a city called 'Miletus' and the earliest philosophers as far as we know and again remember history is mostly a guessing game because we're always trying to figure out what happened on the basis of incomplete evidence so we don't really really know what happened six hundred years before the birth uh... jesus but we have some ideas and most of them come from historical writers uh...like aristotle at for instance and Theophrastus and there are others who are writing about this period and we have those writings so a lot of it is pieced together and so we're not saying that no one ever had these ideas before it's quite possible that there was a person before this period of time who had a lot of similar ideas but we don't have anything written down which have survived which indicate that this is so what we have now the best evidence suggests what we're going to call philosophy um... originated in Miletus roughly six hundred years before year one and in particular with a individual named Thales and Thales uh... was roughly born in this 620's a six hundred and twenty years before year one we don't really know because the ancients didn't really keep birth records they weren't interested in when someone was born uh... there were more interested in when someone dies so we have really complete death records we know that he died in five forty six now notice that these dates go backwards and that's because of course we're counting down to year one whereas where we are now in the year two thousand eleven we're counting away from year one so uh... it's not weird to be born in six twenty and die in five forty six uh... that's the way we date things back then and thales is a real interesting person uh... there's a lot that can be said about him and i'll spend some time talking about thales and the people around him other uh... greeks, Anaximander and uh Anaximenes uh... those are the hard to say, wait until you see how there're spelled okay so And these are collectively are known as the 'pre-Socratic philosophers' and there're some other ones we'll talk about there is a whole section on pre socratic philosophy don't worry about why it's called that for now but that's what we'll talk about that later but that is what it's called so these thales for instance was interested in questions about the makeup of the physical world he wanted to know whether or not there were some fundamental stuff some thing out of which all of the other stuff was made and he also rejected any kind of supernatural explanations for the things he was interested in and these kinds of twin interests and ideas here came to dominate a lot what happened in early Miletus uh... these...uh, excuse me in early Miletus in other words uh... the philosophers who were uh... the earliest philosophers who came before Socrates plato and aristotle So let me give you some example of the kinds of things thales was interested in he was interested in the shape of the earth and this has been something that people had been interested in for a very long time and there were various theories about the shape of the earth uh...but the reasons given for believing in the shape being this or that were usually uh... uh... related to religion or being revealed by a god or being revealed in a trance so what thales did was to try to give arguments that we could figure out what the shape of the earth was ourselves if we paid close attention to our environment so for instance he famously claimed that you would have different experiences of a ship coming in from sea or going out to sea depending on the shape of the earth so if the earth were round you would expect the ship the disappeared gradually part by part whereas if the ship were excuse me, if the earth were flat you would expect the ship to just disappear altogether all at once as it faded away uh... gradually and that experience bore out the first claim that you would see the first part, the lower parts of it disappear first and higher parts of it disappeared later because it's going around a bend or a curve so secondly also it had been known for a thousand years at least the babylonians kept very, very meticulous records of eclipses and the activities of the uh... stars and planets and so on and it had been known or thought that uh... what happened during an eclipse was that the shadow of the earth was being cast on the thing being eclipsed, so when the moon is eclipsed that's earth's shadow that you see and thales argued that since this the shape of the shadow of the earth would give you some evidence to the shape of the actual earth itself since that was the thing that was casting its shadow and that the shape of the earth was circular perhaps spherical uh... and so that would give you some good reason to believe that that was the shape that the earth actually had so now notice again what's important, the point that's being made here is that thales is not the first person to ever suggest that the earth is round or spherical people had suggested that before for instance there are people who claim that the earth is the shape of an egg and this is because it was revealed to them that way. There was some mystical divine source to the idea. Whereas what thales is arguing is that well even if that is revealed to you and so he is not particularly criticizing belief in gods here even if that is the case we still ourselves can determine it so that we can tell what the shape of the earth is by by thinking about it by looking carefully now thales also thought that he had an answer to this idea uh... the question was everything fundamentally unified some how and though people debate about exactly what he meant by this but he's famous for, or at least aristotle cites him as saying that the fundamental principle of reality is water somehow that the...that's taken to mean that the original state of the universe was water or that things are somehow still composed of water so that a piece of wood would be like ice really really compactified but the basic idea that thales had and that other pre socratic Miletian philosophers these earliest philosophers had was that there was some fundamental stuff which existed sort of un formed and contained within it the essences of everything else and somehow that stuff was transformed into the many things that we see around us and that was a basic idea that these guys had. That there was some basic fundamental stuff out of which other things came and then they would debate about well, what the fundamental stuff uh... and they would give arguments so for instance some people would claim that, uh, water is a better candidate than uh... say for instance fire because water uh... is frozen and turns into ice and can be in uh... also evaporated into gas forms and so we can see already how it occupies different states and then people would debate so that's just... now to get into these debates, we'll touch on some of the pre socratic debates in that section but just to give you a flavor of the kinds of things that these guys were interested in and also uh... to try to show you that they weren't merely saying that this was revealed to them but we're trying to discover the fundamental nature of reality on their own okay and also they give naturalistic answers so whereas earlier for instance an earthquake might have been thought of as uh... an expression of the wrath of god for not following some rule of theirs thales argues that these are not appropriate explanations that the world around us is an orderly system which is constructed according to certain kinds of rational principles and that we as rational human beings can kind of try to figure out what those rational principles are for instance thales argued that what an earthquake was was on analogy to a boat in the water when the boat is floating and the wind blows the boat rocks back-and-forth and someone on the boat would think of that as a quaking and so an earthquake, thales hypothesized must mean that the earth is floating on water and rocking back-and-forth like a boat would now of course we know that that's wrong uh... we talk about tectonic plates and pressures um, causing earthquakes we don't talk about earth floating on water in fact we don't think that islands technically uh... float on water so uh... we know that thales is wrong in these instances but notice the approach that he is taking uh... is radically different we can figure out what an earthquake is and there's kind of evidence that it might be something like this given that there's a similar phenomena so thales is here thinking that we ourselves have the abilities to figure out the way the world works and uh... he's not necessarily criticizing religion there can still be gods and there can still be divine revelation uh... that can be one way of knowing but thales is advocating another way of knowing one that involves use of human reason so let's take a second to sum up the things that i've been talking about in this first part of the lecture I've been trying to... one theme I've been trying to emphasize is that philosophy isn't really distinguished by the questions that it asks because people've asked those questions all the time they've always ask them really what makes uh... so those questions are just common to human beings what makes something philosophical is rather the approach one takes to the questions themselves rather than the actual asking of the questions because i want to say that Gilgamesh was asking the same question about the meaning of life and immortality that a philosopher might ask but that he his way of answering it is very different whereas he wants to appeal the divine revelation the philosopher says that we don't appeal to divine revelation so the pre philosophical way of thinking is really characterized by those two claims there on the bullet points the first is that divine revelation is the only source of knowledge. Human beings aren't capable of knowing on their own and secondly that the physical world around us is controlled by these supernatural personalities and they can intervene at any point that they want to enforce their will so it's up to to us to try to figure out what they want and uh... make them favor us as opposed to disfavor us so that's what i'm calling the pre philosophical way of thinking thales and his contemporaries deny both of these claims so rather then divine revelation thales says reason argument and observation are sources of knowledge about the world so now notice combined in there are things we would call science, things that we would call philosophy uh... and part of the history of this is the gradual separation of things which we called science and things which we call philosophy but at this time they're all wrapped up into one and people don't really recognize a distinction between philosophy and science except for that they're different kinds of philosophy so natural philosophy would have been the philosophical study of the natural world as opposed to...uh, so the way that physical objects move would have been thought of as a branch of philosophy and indeed newton who...who writes his book on gravity etc...publishes it under the title 'the mathematical principles of natural philosophy' so newton call, referred to what he was doing as natural philosophy so we'll see a distinction get made eventually but doing it historically these ideas are all wrapped up so reason argument and observation are sources of knowledge and that's a denial that revelation is necessary for knowledge but again be careful it's not a denial that revelation can be a source of knowledge so there is no conflict with religion in the definition of philosophy that we're talking about here you can be a religious philosopher, you could be someone who thinks that reason and argument are sources of knowledge and also someone who thinks that God can reveal knowledge to us if he, she, it so chooses so there's no conflict between religion and philosophy the only conflict here is between views on which human beings are incapable of finding answers to these questions on their own and views on which they are capable of finding answers to these questions on their own. Now of course this doesn't mean that we'll like the answers that we find we may find out the answers to be contrary to what we thought hoped etc but the idea is that by reason observation and careful reflection we'll be able to discover the way things are and that was really what thales and the other pre socratic philosophers thought distinguished them from the other way of thinking about the world where human beings are supplicants always asking to be told but never taking action never figuring it out on their own and what this amounts to for thales really is an emphasis on mathematics and at this point in time in history of the universe geometry in particular so I want to stop for a second and say something about geometry because it really is important for understanding this whole period in ancient philosophy so it's hard for us modern contemporary people to think about geometry in the right way geometry seems to us to be something you learn in 7th grade, some very basic, simple math uh... something you memorize some formulas for squares and circles and area and blah blah and then later on you learn more interesting and important things like trigonometry and calculus but of course that's not the way the ancient people thought about geometry Geometry actually originated not in Greece but in Egypt for a very practical purpose so if you think about the word 'geometry' you actually see its original purpose encoded so the words comes from 'geo metria' 'geo' meaning Earth and 'metria' meaning measurement and so 'geo metria' is literally the measurement of the earth and the Egyptians needed this very practical ability to measure areas on the ground because of the flooding of the nile which was a regularly scheduled event so to speak in Egypt even to this day so the ancient egyptians would set their calendar by the flooding of the nile they would say 'that's day one right there, when the nile floods, that new year's, that's month 1' uh... so but uh...this is a very reliably reoccurring disastrous event and of course if you own property and you have a fence up and the nile floods and your fence goes away then you need a way to reestablish where the fence went so you need a way to say how wide five hectares of land, five square hectares of land really is you need a way to say where that fence actually gets reestablished um, now thales gets the credit um for introducing geometry into greece the story goes that he went to egypt, as was common for greek men in their education to spend uh... the last year of it abroad So thales goes to egypt and studies with egyptians and sees them doing this, measuring the earth and he brings geo metria back to greece but instead of using it for this practical applied purpose thales becomes interested in proving theorems about geometry he becomes interested shown for instance that if you take two right triangles who have a certain area and combine them you can always make them into a square and the area of the square will have exactly the same area as the sum of both of the right right triangles so, very basic facts about geometry...these are things which are known by reason and this method becomes something that the ancient philosophers really become transfixed by and the history of philosophy is a struggling with whether this is really true or not but its one of the very earliest ideas uh... philosophical ideas that people had and that was that there seems to be some things which can be known directly by reason and that reason is a special sense in a way kind of like seeing uh... but in a different way it gives us access to the way things have to be the way things must be and this becomes a very important theme uh... at and it's all analogized to this idea that the in geometry what do you is you start of the set of axioms which are indisputable which are known directly by reason and then you expand from those and prove various other truths about reality the way reality must be which you didn't know before hand so for instance one of the axioms of geometry is the parallel postulate the idea that two parallel lines will never meet so if you look at these two lines of text on the bullet points here those two lines are parallel to each other and you don't need to walk the lines and make sure they never cross you can kind of just tell by thinking about it they'll never cross the definition of a line on which all of geometry is founded in some sense simply a line, a straight line is the shortest distance between two points you can't really prove that there's no way that you can say ah here's the argument for why that's the case it's just something that you can kind of see has to be true but not see with your eyes seeing with reason this idea becomes extremely influential that the way that mathematics works is kind of a a guide for how we'll discover the way reality works by using reason to reverse engineer the principles which govern the way reality is that was in some sense, i think a unifying theme uh... all of ancient philosophy and as will see, because we'll go through these periods of time in philosophy we'll see this idea gets developed debated refined and it's still a current theme of uh, uh philosophers today now of course the other claim here is this commitment to the world being natural and by natural what they mean is that it's explainable assuming rational law like relationships you're not going to appeal to the anger of Zeus to explain what lightning is but rather you'll appeal to some natural phenomenon which generalizes and gives a nice universal explanation for why things work that way so that's what i wanted to say, suggest really is at the heart of what philosophy is philosophy is this commitment to the claim that we're going to find out the way things are that's how it begins that's how it sees itself self-consciously at its origin. It sees itself as a way of standing against the idea that human beings are incapable of achieving this kind of knowledge so let's turn now to our second way of thinking about what philosophy is because remember that's the overarching goal of this first lecture to give us a sense of what philosophy is what philosophers do so the more traditional way of doing this is the start with the meaning of the word 'philosophy' there's an interesting history there so this I think is probably well known and so we won't spend overly too much time on it but we will spend some time because its standard and not everyone knows it perhaps. so, the word 'philosophy' again come from greek and that's the interesting thing about English is that the more latin and greek you know the more english you know because most of our important words uh... come from those sources so now as you probably know like I said uh...the source of this word is 'phila sophia' 'phila' meaning love and 'sophia' meaning wisdom so this is rather famous now what may be is less famous is who coins this term it was actually originated by Pythagorus and Pythagorus was alive in five seventy bce uh... so now remember thales was alive in six twenty so you might ask yourself well was that before or after pythagorus? and of course the answer is that thales came before pythagorus since six twenty is further away from year one than five seventy is uh... and we don't know a lot about the Pythagoreans although they're very interesting and we will talk briefly about pythagorus and his followers when we talk about pre socratic philosophy more fully instead of just this introductory way Pythagorus is more famous for his theorem A squared plus B squared equals C squared which is a theorem of geometry and it describes the behavior of a right triangle and the relationships of its sides to each other so that's basic uh... geometry but pythagorus suggested that we should be called philosophers as a way to distinguish what they were interested in from another group of people which they called the 'sophists' this really is uh... the way that socrates and plato saw the line up so the sophists were a loose group of philosophers uh... who were united by a couple of themes and these are the themes here excuse me, these are the themes here. So 'sophist' of course means 'wise people' from sofia there and in english we still use this word so that's where we say 'sophisticated' means sort of wise/intelligent but also as sophisticated has a kind of negative connotation if you in certain uses something can be too sophisticated and that's retaining some of this older use of the world; 'sophistry' so sophists were often skeptics a skeptic is someone who thinks that we can't know what the truth is uh... or more radically someone who thinks there is no such thing as the truth and so they would often argue that look you know whatever you think it's true that's just true for you and there's no such thing as The Truth of the matter, or anything like that uh... so famously uh... a sophist named Protagerous proclaimed that man was the measure of all things people took that to mean that look, whatever you think is true, is true (for you) philosophy in this sense of the word was opposed to that kind of view philosophy stood for the search for the truth wisdom being kind of the idea that we are looking for the truth here so a philosopher was someone who wanted to know the way things really were they had a...uh, they didn't know so it wasn't as though they actually had that knowledge but they wanted to know uh... and so they saw themselves more in line with the early Miletians namely in the sense of thinking there is a truth and that we're able to discover it we haven't discovered it yet but we want to discover it we're sort of wounded and that's where the word 'wonder' has its roots from this kind of wounding by these intellectual questions you just are burnt up with curiosity over whether there is a fundamental stuff out of which everything else is made or what the real nature of reality is uh... uh... is movement possible these kinds of questions eat you up at night uh...so that's the idea of the philosopher as the seeker of truth as opposed to the sophists who don't really care about the truth and instead are interested in power and rhetoric where rhetoric is simply the idea that you convince the other person that you are right and so we'll see some of this get played out when we look at socrates and the Platonic dialogues where socrates talks to a famous sophist whose name is Thrasymacus and we'll see this idea that well he'll only talk if he's paid he doesn't really love it he's just doing it for the money and he's only interested in power uh... who's controlling other people as opposed to the philosopher who's really interested in the truth, is a seeker of knowledge and of wisdom so now this adds to the previous way of thinking so it's still a way of saying well look we can figure out what's going on but it adds a deeper dimension of commitment to finding out the way things really are and merely convincing other people that you're right okay so finally now coming to our third and final part of the lecture we can talk about the various traditional branches of philosophy and the questions that philosophers deal with or some of them anyway the first branch of philosophy perhaps the most fundamental although we can debate about that often thought to be the most fundamental is the branch known as metaphysics which is defined as the study of the ultimate nature of reality now where the word 'metaphysics' comes from uh... it just comes from the name of the book aristotle wrote on this so there's no real special meaning attached to uh... metaphysics uh... aristotle wrote a book on physics where he talked about how objects move and then he wrote a second book on what it meant to be an object at all and on what kinds of objects could exist and so on and that simply became known as the book after the physics 'after the physics' you say in greek 'ta meta ta physica' after, meta, physics so it became shortened through history simply referred to as metaphysics and that's where the word comes from often students are disappointed that there is no special hidden meaning to the term 'metaphysics' but even so you can see that that that it's an appropriate title because meta means something that comes before uh... in physics uh... the study of physical world so often metaphysicians think that what they're interested in comes prior or is at a somehow higher level of abstraction than what physicists are interested in physicists are interested in describing the actual laws of nature and metaphysics are interested in describing the way things could be the way things have to be the way they must be so what kind of questions then do the discuss well we've already looked at one of the basic questions in metaphysics excuse me which is whether there are fundamental parts out of which everything else is made or whether as the famous story goes it's turtles all the way down Now if you don't know this story let me just tell you really quickly uh... it used to be wondered what the earth rested on and of course uh... atlas was thought to hold the earth on his shoulders in greek mythology and when people asked 'well, what does atlas stand on?' and then someone says he stands on a giant turtle and then someone says, well what does that turtle stand on? and then someone says, that turtle stands on another turtle and someone says, well what does that turtle stand one? and the teacher replied, 'son it's turtles all the way down' so it's a turtle on a turtle on a turtle and so that's a joke of course but you can see what the point is supposed to be is there an infinite series of smaller parts and smaller parts and smaller parts and smaller parts? or is there some fundamental level at which parts stop? and there is a basic set perhaps of things out of which uh... other things are constructed that's a basic question in metaphysics and and there are various answers to it uh... uh... it was thought for long time that there was a basic stopping point which was known as the atom and the greeks came up with that word. In greek atom means 'a tomos' or unsplittable a basic element which couldn't get any smaller. We'll look at some early greek versions of atomism uh...but modern physics suggests that the atom has parts quarks, electrons, protons. Those things have parts quarks some suggest that those are composed of strings so it's a open question right now still unresolved whether there is a smallest part or whether it's turtles all the way down so we'll look at some of the historical positions on this which are very interesting so a related question is one about whether reality is completely physical or whether there are non physical elements to reality this a very deep and vexing question which has a long history so uh all kinds of things have been thought at one point were candidates for being non physical these range from everyday objects like numbers one two three five seven 100 some philosophers have argued those are non physical objects things like god being perfect unchangeable existing at all times uh... some have argued that um... uh... moral facts that it's wrong to kill innocent people for no reason is a non physical fact about reality which can't be captured by any physical thing out there and um... uh...these transcend from simple things like ghosts and ectoplasm all the way to the perfect divine unity so that there are of course excuse me I almost forgot another main candidate for being non physical is the human mind or whatever makes humans human so we'll look at various proposed metaphysical schemes where things are physical or not physical uh... very deep and perplexing questions here now of course another deep and perplexing question which we'll look at is what the nature of causation how does one thing cause another. It seems to be commonplace in our ordinary experience we know that changes are brought about through cause and effect and so the concept of change the concept of cause and effects what they are in the world is going to be something that philosophers are very concerned about metaphysicians another very large branch of metaphysics is uh... questions about whether the will is free whether uh... my actions are determined uh... by laws of physics for instance or by god's foreknowledge are the traditional ways of putting it now in this class we won't be focusing too much on these issues although they are central and deserve to be focused on i usually focus on them in my ethics class where issues of freedom and moral responsibility arise and in my philosophy of religion class where issues of freedom and the problem of evil and god's foreknowledge come up so uh... although and there's just not enough time to cover everything so free will gets sort of left on the side in this class although uh... i've always felt guilty about that and maybe now in this new online format might include some lectures on it but uh... because i have them from the other courses so I'm not sure but i'd be interested to hear what people thought about that so then concluding this is um question about what exists what does it mean to exist? uh... Do numbers exist? If so how, what does it mean to say that something exists physically or something exists non physically what's the difference there? so when you're talking about these kinds of questions which focus narrowly on existence people have uh... often referred to it under the term 'ontology' and 'ontology' comes from the greek word 'ontos' meaning being and 'ology' meaning study of so ontology is the study of being or what it means to have being and uh... these kinds of questions are inherently metaphysical although sometimes you will use ontology you will hear the word 'ontology' being used to talk about what a particular person thinks is real so in your ontology you might include things like numbers ghosts god persons tables chairs dogs cats electrons quarks you might exclude things like numbers gods cats etc so debates about ontology are debates about what has existence what does it mean to have existence and we'll see some of these ancient people were very interested in this question but it's also one that we still are dealing with in are contemporary times okay so on the flip side of that so on the one hand we have questions about the nature of reality what is really real if that makes any sense and how is that reality on the other hand we have questions about how we come into contact with that reality how we know about so the greek word for one kind of knowledge is 'episteme' therefore epistemology is the study of knowledge now there are various questions epistemologists addressed one of the more fundamental questions is what is truth what does it mean for a sentence to be true the traditional answer the one which seems commonsensical that somehow our language describes reality and sentences are true when it describes it correctly leads to all sorts of interesting results in metaphysics namely that there must be something out there correctly described by the things that we say and talk about and as you'll see this is what starts a lot of trouble uh... maybe therefore it even leads us to believe that numbers have to exist or even possibly that all things have to exist because we can talk about things which don't seemingly exist so there all sorts of questions about uh... the relationship between things we say and think and the way the world is and those are epistemological questions so now of course the big question in epistemology is what knowledge it is what does it mean to know something? and we'll look at various accounts of what that means uh... plato theory of knowledge which is fairly well developed and this is still in the area of contemporary debate so now of course we want to know what the difference from is between belief and knowledge so one thing the you can say is what seems like you can believe things that are false but it doesn't seem like you can know something that is false well, so these are different states then what's the relationship? uh... traditionally people have thought knowledges belief plus something else and have wondered what that something else is more contemporary issues take a knowledge... knowledge first view and say well knowledge is we know we know things and then belief must be somehow less than knowledge and then they look for what's missing so there are various views about what this relationship is and we're not going to really talk about them in the class but for people who are interested later these are going to be be very important questions and of course as i just said we want to know how this thing is related to truth merely having a true belief doesn't mean you know it for instance it could be that you have a belief that's true but it's accidentally true a famous case of something like this would be for instance maybe looking at a clock which is broken it's on the wall it's says four o'clock as it happens it turns out it really is four o'clock when you look at the clock so you form a belief that it's four o'clock it's true that it's four o'clock you have some reason to believe that it's four o'clock o'clock the clock has been reliable in the past but it doesn't seem like you really know it and then people debate this issue. Do you know it? do you not know it? if so why not so there are interesting questions about what the general concept of knowledge is now here's one that the history of philosophy uh... has struggled with and one that we'll be looking at a lot in this class assuming we do know things where do we get it? and as we've seen already the early philosophers had this mixed idea that there are some things which are knowable by reason like that parallel lines don't cross and that the shortest distance between two points is a straight line and then there are other things which you know by the senses like that the shape of the shadow of the earth is spherical or gives us reason to believe that the earth is spherical etc so uh... there's a uh... large dispute about what the real sources of knowledge are and we'll see um... that uh... one popular interpretation of the history of philosophy this actually was made popular by kant who looked back at the history of philosophy and said look here's what you see and lots of people have agreed with him is namely a struggle between what are known as rationalists who think that knowledge come from reason and is all based on mathematics and logic and stuff like that and those were called empiricists who believe that science and empirical observation are the real sources of knowledge so there is a way of looking at the history of philosophy where these views are fighting and the earliest view as you might have guessed is a kind of rationalist view where the senses are downplayed and science comes in later as a challenge to this kind of view and so that's one way of looking at the history of philosophy and we'll roughly approach things that way although I'll point along the way where people disagree here's another question about epistemology how you know that you know something when you in fact do know it so for instance rationalists like to think that there's a way of telling that you know something it it there's a certain kind of experience uh... a rational kind of compelling a forcing, a feeling of forced to believe something when reason tells you it has to be that way like for instance when you think about the parallel postulate that parallel lines cannot meet you know that that's gotta be true you know that you know it you have knowledge that that's true and you know it because it feels special in a sense now of course there's been a debate about that and we'll look at the various counter examples in fact it turns out maybe the parallel postulate is itself one of these counter examples although people have responded that it can be interpreted in a way that's consistent so we'll look at those kind of questions now of course is another big question uh... what about the skeptic? is a possible know anything at all? the skeptic says look you don't know that the laws of nature are necessary and universal you don't know that the physical world exists you don't know that the world wasn't created five minutes ago and that all your memories aren't false so there's a real serious challenge here uh... how do we how can we be sure that what we have is really knowledge uh... as opposed to something else and we'll look at that there are some serious arguments for skepticism we'll look at the way that people tried to deal with those arguments okay now metaphysics and epistemology are clearly related to each other as two sides of a coin are so as soon as you say what's real you're telling me that you know what's real so you're already talking about you must have some way to know that the things your talking about are that way now of course as soon as you start talking abut what knowledge is you talk about which things can be known and so which things are real and so the two are intimate related... intimately related and we cross back and forth from talking about epistemology to talking about metaphysics but it's extremely important to keep them clear no matter how related they are they are different types of questions one a question about what is real, what is out there the other a question of what we know a question about us and we'll see a gradually a separating at these uh... as we move through this stuff now uh... apart from these two major branches we can also see the branch of uh... the branch of philosophy known as ethics ethics can be informally defined as the study of right and wrong or good and bad where what do we mean right actions good persons which things should we not do which things should we do it's in general the study of which things have value what is the nature of value that's a question uh... which uh... ethicists wanna know what does it mean, are there objective values that are things which all persons have to value? or there're really only relative values? so now if you think about sort of value theory in this broad sense that's going to include the branches of philosophy traditionally known as aesthetics and political philosophy so aesthetics is the study of the beautiful what's the nature of art? uh... but really it's a question about what's valuable uh... whether art is valuable what's the the relation of beauty to value and of course political philosophy questions about what the best form of government is these are all value judgments and there's relationships between these three although ethics aesthetics, the study of art and beauty and political philosophy uh... are separate they can all be branched under one major category known as the study of values so now ethics more traditionally construed as the subject of the study of right and wrong, good and bad, um, what we're interested in there what actions are moral is abortion immoral? uh... is abortion moral? or is suicide immoral? is suicide moral? lying? etc now of course the big question in ethics is the skeptical one the one about whether we can know the moral truths or whether there are any such things as moral truths in the first place the relativist thinks there's no such thing as real truth its relative to you or this or the other thing whereas relativism about mathematics has never been very popular relativism about ethics remains extremely popular and so there's a serious question about whether it's true or not uh... and uh... a large part of an ethics class is is spent dealing with the arguments for and against relativism now another question which it falls under this category but which is not so much addressed by contemporary persons as it used to be by ancient persons this is the question of what kind of life one should live is it better to live a life of seeking money or of seeking intellect? or seeking pleasure? and there are various answers to that question in history of philosophy we're not going to be talking too much about ethical questions although we will talk about uh... briefly some of the issues because socrates was interested in them you can talk about socrates without bringing these questions out okay but this is primarily a class on metaphysics epistemology and primarily the history of that uh...and the way it interacts with what we think currently okay so finally then the last branch bringing this all to a close the study of logic which can be defined as the art of good and bad reasoning or of good and bad arguments and so notice that this is extremely important because um... earlier i was talking about philosophy as the use of reason and argument to discover what is true or what can be known if that's the case logic is extremely important because it's our science of determining which arguments are good and which reasoning is bad and so it occupies a very central place and we will touch on some logic in fact I'll give a brief introduction to syllogistic logic, the logic of aristotle and extend it sort of to truth-functional logic, contemporary logic, just briefly enough to uh... hopefully interest one in taking a logic class uh... because logic is something that improves one's ability to reason and uh... even though it's related to mathematics in a certain sense it's more fundamental perhaps than mathematics and hopefully uh... mathematical truths are expressible in terms of logical truths or at least that was the hope of one group of philosophers and maybe by the end of the class uh... we'll be position say something about that uh... although i'm not sure so that concludes