Plato’s Epistemology: From Innate Ideas to a Grasp of the Forms by Leonard Peikoff, part 10 of 50

Now I said that one main purpose of Plato's whole philosophy was to answer the sophists, to show that objective knowledge is possible. But here we immediately have a question. How can we ever come to know the forms? After all, they constitute a completely different world, a non-material world, and as such not in space, not in time. And yet here are we on Earth, limited by our bodies and our senses, how are we ever to come in contact with them? Well, of course, Plato answers by thought. But the question is how does thought down here ever come in contact with the forms up there? And of course up and down are here simply metaphors because the forms aren't anywhere, they're not spatial. Well, the answer to this we have already actually touched on last week. We proved, at least in Plato's opinion last week, that we must have been in contact with the world of forms prior to this life. We must have lived in the world of forms in a preceding life. And Plato believes that he's proved that and therefore adopts intact the whole Orthic Pythagorean view with the wheel of birth, successive reincarnations, and the ultimate goal being escape. But in any event, our souls knew all the forms and therefore all the laws and therefore was actually omniscient prior to its birth in this world. When, however, it was immersed in the body and thrust into the Heraclitian flux, it had what modern psychologists would call a birth trauma. And the effect of that is the soul forgot all the things that it knew. Put in modern terms, all that knowledge descended into the unconscious. But it is still there, it is still in us, it's still real. What we call acquiring knowledge, says Plato, is really not acquiring new knowledge at all. It simply is a process of digging out from your subconscious or unconscious what is really already there. Knowledge is a process of remembering, of reminiscence, and this is Plato's famous theory of knowledge as reminiscence. And it's in Greek, the theory of anamnesis, a-n-a-m-n-e-s-i-s, anamnesis simply means reminiscence. Therefore, for Plato, there is definitely innate knowledge, knowledge of reality born in us. The senses, the physical senses, are not means of getting new knowledge of reality. What then is their function? Does Plato believe that if he took a young baby and gouged out his eyes and pierced his ears and generally mutilated his senses, he would then be able to go along merrily and still remember the forms? No. Plato says yes, we definitely need the senses in the early stages of knowledge. Not to teach us something new, however, but to serve as a stimulus to jog our memories. The best analogy you can think of, the one I was taught when I was first taught Plato, is imagine that 20 or 30 or 40 years after you have left college, you come across an old faded yearbook with pictures of your classmates and your grandson is busy jostling it back and forth, so you get only a fleeting glimpse of a faded photograph. Now, if you didn't know the man in the photograph from 20, 30, 40 years back, you'd never get anything from that little stimulus. But given that you knew the man well, even if you have forgotten him completely, that corrupt, imperfect, flickering stimulus is enough to remind you and you say, oh yes, Jones, I remember him, I haven't thought of him for years. Well, for Plato, in essence, that's true of all knowledge. You see a few horses and you say, ah yes, hoarseness, now it comes back to me. But after an initial period of thus stimulating your memories, knowledge thereafter is a matter of looking inward, not of looking outward. It is a matter of turning away from the world of introspection. Because we have in us all the basic truths and laws and concepts, and what we do is simply look in, find them and proceed to deduce their consequences logically, quite apart from any further sensory observation. Now, this view of knowledge, as you know, is called rationalism. But now with Plato, we have a fully worked out answer to the question you asked several times before. How does reason operate if it doesn't base itself on sensory data? Heraclitus and Parmenides and those early figures were rationalists, but if you had asked them that question, they have no answer. Plato has an answer. His answer is, reason is capable of acquiring knowledge apart from the senses because we are born with innate ideas. Now, from the time of Plato on, rationalism therefore acquires a fuller definition. It becomes the epistemological theory that knowledge is acquirable solely by reasoning from innate concepts, and that sense perception is in principle dispensable. Except, of course, as a stimulus. It's called rationalism, of course, because Plato called the faculty which studied universals reason. It's the idea that reason alone can give you knowledge apart from the senses. Now, I should say for accuracy that this definition of rationalism holds true descriptively of philosophers in this camp up to the 18th century. Kant introduced in the 18th century a quite different version of rationalism. A variation on Plato, but nevertheless a significantly different one, and rationalism from the 18th century to the present is quite different and does not believe in innate ideas, but that's not the subject of this course. Now, what proof does Plato offer of innate ideas? Well, in general there is only one argument in favor of innate ideas, and then it's simply a matter of all of the various forms of it. The general argument for innate ideas raised by Platonists from Greece to the present is, we have a certain type of knowledge that we could not have acquired from sensory observation, but we have it. Therefore, it must have been acquired from somewhere else. We must have got it from some means apart from the senses. We must have been born with it. It must be innate, and then the various sub-arguments under this are simply specifications of the types of knowledge which various philosophers feel could not have been acquired from experience. For instance, Plato himself mentions the knowledge of perfection. Remember I argued too last week, or he mentions the argument from the order of knowledge, from man's ability to define and classify, which in his opinion, remember, presupposes that we knew universals prior to this life and we couldn't have acquired them from sensory particulars. And he gives us several other equivalent arguments. One famous, although very weak one, is given in a dialogue called Mino, M-A-N-O, in which Socrates says to a man who owns a slave, bring your slave boy in, and this boy is completely uneducated, and I will show you that he possesses knowledge of complex geometric theorems that no one has ever taught him. I will simply elicit them from him by judicious questioning. And you watch and see. I am not going to tell him anything. I'm simply going to question him. And sure enough, Socrates, by a series of questions, without nothing in the declarative form, everything interrogative, the boy at the end comes out with a complex geometric theorem. And Socrates draws the moral, you see, he had it in him all the time, he just needed to be reminded of it. Needless to say, critics for centuries have said Socrates was feeding him information right and left, and doing it in the form of questions. It's not as crude as the following, but what it amounts to is, don't you see that the angle of some of the triangles is 180 degrees? And the slave boy says, yes, you see. So that is not very convincing, but famous nevertheless. Does Plato offer any proof of the immortality of the soul, which is an essential ingredient of this theory? Well, in the dialogue The Phaedo, P-H-A-E-D-O, he gives four famous proofs for the immortality of the soul. I mentioned one of them last week. That was implied in the second and third arguments that I gave you, that the soul must have existed prior to the body. And that in essence is a proof of the immortality of the soul, if it were valid. Because if it could exist prior, it could just as well exist after the body. Because the essential point in an immortality argument is to prove the independence of the soul from the body. And Plato would have done that. He gives three others in The Phaedo. They are very poor arguments, and I will not take your time discussing them. If you're interested, I'll be happy to tell you in the question. In any case, he is convinced to his satisfaction that he has established the existence of innate ideas. And this becomes a challenge to Aristotle to explain, if he can, how is all knowledge possible, assuming man is born without innate ideas. And Aristotle accepts that challenge and proceeds to define for every category of knowledge, as Plato said, we couldn't get from experience how you get it from experience. And we'll see when we get to Aristotle next week. Now let us continue with Plato's epistemology. Let me give you some detail on the steps you have to go through to recollect and reawaken all of your knowledge. You must, says Plato, pass through four stages on the road from ignorance to complete mastery of the entire universe. Now I must amend that there is no real ignorance, but ignorance in quotes, the ignorance of a baby who doesn't remember it. He illustrates this by a famous divided line, which has four segments, then you travel up the line. And this is called Plato's theory of the divided line. But the line is not too important for us. What's important are the four stages. The first stage he calls the stage of imagining. This is the stage in which you are wholly ignorant, confused, and unenlightened. As far as cognition is concerned, you take all superficial appearances at face value. You are like, in effect, a baby. You are a baby. This is the stage that babies, according to Plato, begin at. You do not distinguish in this stage between dreams and physical things. You dream that somebody hits you, you wake up mad at him. Because you take the dream and the physical thing as interchanging. You look in a mirror and you see an image or reflection or shadow of yourself, and you think it's another person. You do not tell, you can't even tell the distinction between images and physical things. In other words, you are simply being bombarded with an unidentified stream of sensations. Morally, the moral counterpart of this first level of imagining, you accept anything that you want, any desire, utterly unthinkingly. So this would represent, in effect, the moral mentality of an animal, which simply desires and goes out and gets what it wants without any question of right or wrong, or of a sophist, who does the same thing as a matter of philosophic principle. This is the lowest mentality there is. Now we move to the second stage, which is what Plato calls the stage of belief, or also the stage of opinion. Now by this time, you've grown some years, you have learned to distinguish some facts in regard to the physical world. You can now tell the difference between fact and fancy, between physical objects on the one hand and dreams or images on the other. And you've even risen to the level where you've made a variety of scattered empirical observations and some crude, approximate, rough generalizations, on the order of empirical rules of thumb. Now of course, at this stage, you do not know why any of these facts or generalizations hold true. And therefore, you have no capacity to be certain that they will continue to hold true. For instance, you've observed that if you follow any given man around long enough, he drops dead. But you have no idea why. All men are mortal. That just happens to be a brute observation. Or if you went in for specializing in triangles, you kept measuring them and the angle sum kept coming out to be 180. But as far as you know, the next one might be 179 or 250, who knows. So you have a certain degree of probability here, but not true knowledge. And that is why Plato calls this the stage of belief. You believe certain things, but you don't yet know them. And of course, there's other reasons why you don't have knowledge yet at this stage. You're using your senses to study physical objects, and of course, they're not real, they're contradictory, they're in flux, they can't be known, and the senses are invalid. So for all those reasons, we only have belief at this particular state. The moral counterpart on this particular level would be the average man, who has absorbed a certain set of rules. You shouldn't kill, you shouldn't cheat, you shouldn't tell lies, but he couldn't for the life of him say why, or prove that they're universal or in what context they're universal. They're just rough and ready common sense rules of thumb. Now notice your opinion or your belief, Plato uses the two synonymously, might be right, and it might be wrong. But even if it's right, it's still simply an opinion, a belief, it isn't yet knowledge. Stage three, going up the line, is the stage he calls thinking. That's the point, the stage where science begins, which means having gone through the stimuli of the preceding stage, we now are able to turn away from the physical world, the sensible world altogether, and focus our attention on the forms. Individual, separate forms at first in this particular stage. And the crucial thing we find is that every time we grasp any one form, it illuminates and makes intelligible everything that we had observed on the preceding levels. As soon as we grasp a form, that explains why the rules we had earlier simply empirically observed are true. Now this is true of every level, every stage explains the preceding stage, and so we can illustrate this by imagining for a moment, that for some fantastic reason which I can't think of, you wanted to go in for a study of the shadows of a horse, a particular physical horse's shadows, and you had never seen the horse. You simply were watching his reflections, let us say, in a pond, and you decided to study. Well, you could learn something by studying the shadows. They might follow a certain progression, in a certain order, and you might be able to tell that this is obviously not a banana that's involved here, and so on. But you couldn't learn too much, and whatever you learned would simply be a series of brute observations. The shadows move this way and this way, but why they do, you don't know. Now what makes it possible for you even to study the shadows? The fact that there is a real physical horse. Now suppose you turn around and see that real horse after years spent studying the shadows, you'd say, aha, this makes sense of it all. Now I see what all these shadows were doing, and why they were doing what they were doing. The higher level illuminates and explains the lower. Well, that is exactly true of the third level in relation to the second. Only on the third level you discover hoarseness, and when you get to it, and you grasp the abstract nature of horses as such, then everything you observed about particular physical horses now falls into place, and you see how it follows from the very nature of horsehood. So if you want an example of the three stages with relation to a horse, for instance, well, a baby would be the example of stage one. He doesn't know anything about it. He can't tell a physical horse from a merry-go-round horse. The second stage would be, let us say, a racing fan. Who has discovered that certain horses are good mutters, and others aren't that with mutters, and others aren't, and so on, but he couldn't explain why at all, and therefore it's just probability. And the third stage would be the theoretical biologist, or if you wanted a science of horses, the hippologist, and he would deduce from the very nature of horse all the preceding ones. Or if you wanted with regard to mechanical phenomena, the first stage would be the layman who is completely ignorant of mechanical things. The second would be, for instance, a garage mechanic who knows by rule of thumb experience that if you smack this particular thing, the car will start, and if you pour oil in here, it won't, but he doesn't know why. And the third stage would be the theoretical physicist who can tell him the laws from which his particular empirical observations are deducible. On the moral level, the three stages would be the lowest stage, the softest, for instance, the second stage, the average man who may have correct but unexplained beliefs, and the third stage, of course, the moral philosopher who explains the reasons behind those correct beliefs. The general principle is the abstract, the universal, the general always explains the particular, gives you the reason for the particular. Well, at this stage, in the stage of thinking or science, we are almost at the stage of certainty, but not yet. It's not yet true knowledge for the reason that I mentioned at the outset. Namely, we only go to a certain point and then we come against the blank wall of the axioms of the various sciences themselves at this stage. And they are not yet validated. They are simply assumptions, so our whole structure is precarious and is not true knowledge. And thus, we reach true knowledge stage four, true knowledge, where, of course, we grasp the pinnacle, the form of the good. And at that point, we are able to reason down the whole chain and show that everything we had discovered ascending follows deductively from the form of the good. At this point, we have true understanding of the universe. We hit the epistemological jackpot. So, there are four stages and to each corresponds its appropriate type of object. The stage of imagining, which has as its counterpart images. The man is lost in a world of images of the baby. The stage of belief, which studies physical objects. The stage of thinking, which studies the lower forms. And the stage of knowledge, which grasps the good. Each stage makes the existence of the preceding one, of the lower one, possible. And the knowledge gives you knowledge of why and thus illuminates the lowest. Now, these four stages were illustrated by Plato in a famous parable or allegory, which he invented, which is a marvelous story, because it captures not just his epistemology or metaphysics, but the essence of the whole platonic philosophy. And I don't believe any course is ever given anywhere on Plato, in which this story is not told. And so, I want to take five minutes to tell it to you. It's called the myth or allegory of the cave and it is presented in the Republic. Now, imagine for instance that you are all in a dark, dank, gloomy, underground cave. And imagine that you have been prisoners in this cave from the time of your birth. You cannot get up and move around. You are chained at the neck and the ankles. You can only look straight ahead at the wall in front of you. Behind you, unknown to you, there is a group of people that you've never seen. And they are carrying various objects and behind them is a fire, which casts the reflection of those objects onto the wall in front of you, so that you see only the moving shadows of those objects on the wall and are completely ignorant of the actual objects in the fire behind you. Now, you, the prisoners of the cave, would necessarily take the shadows, says Plato, as reality. You've never seen or conceived of anything else. And consequently, you would attach great importance to proficiency in shadow detection. You would, I'm here elaborating slightly to make it more modern, but the idea is Plato's, you would give out your PhDs to the man who best was able to detect the shadows and you would make them the president of the country and heap honors upon the shadow experts, because after all, they're the ones that are the exponents of the ability to deal with reality, as you see. All right, now, says Plato, let us release one of these prisoners. Now, the first thing is he's very stiff. He's been sitting there for years, chained and therefore it's painful. When we take him to the back, he has to shade his eyes at first, because it's awfully bright back there with this big fire. However, at a certain point, his eyes become accustomed to it and he says, so this is what's really going on. I was just looking at shadows. All of us were deluded. He is amazed and we say to him, you haven't seen anything yet. Now, we take him up the long sojourn to the surface of the earth and he emerges from the underground tunnel and he sees this fantastic new realm that he never even dreamed of. He is completely overwhelmed by the variety, the beauty and so on, compared with the dingy dark cave. This he sees as what's really real and the cave world is just a meaningless appendage. Of course, he can't see very well at first up here. He has to keep his eyes shaded because it's really blindingly bright. They did not have New York weather, so he has to keep his eyes down. But after a while, and that's quite painful, but after a while he grows accustomed to the light and he begins to wonder where is it all coming from, all of this light. He finally looks up in the sky and he sees the sun, the brilliant sun which illumines everything, the ultimate source of energy and life. He's reached the end of his journey. Now, he wants nothing but to live up there in the world of beauty and sunlight, but he feels that it's his duty to return to the cave simply to enlighten his fellow prisoners and free them from their delusions. So, he starts back down, but he stumbles because he can't see very well now in the dark. Anyway, he makes his way back to the cave and he finds the prisoners arguing excitedly about some shadow or other. And he rushes in and he says, forget this nonsense. This is all shadows. I have seen true reality. Now again, I'm embroidering a bit, but this is the idea. And his other prisoners say to him, well, what's it like? He says, well, I just can't tell you. It's incommunicable. You just couldn't imagine it. You'd have to see it for yourself. Well, the prisoners are skeptical and if we update the myth, they in effect give him the sanity test. They think he's crazy. And of course, since they define sanity as the ability to deal with reality and thus with shadows, they measure his ability to deal with shadows. And since his eyes are not accustomed to the dark anymore, he does poorly and he fails and they put him to death, which is an obvious allusion to what the masses did to Socrates. In other words, they are hopelessly out of touch with reality. That's the famous myth of the cave. And you see the media, the four stages, the shadows, the physical objects at the back correspond to the first two stages, imagining and belief. And the ascent to the surface of the earth corresponds to the ascent to the world of forms. And the sun, of course, is the standard for the form of the good. The people caught in the cave who are doomed to believe that that is reality are the masses of mankind. The few who can escape from the cave and see the true reality are the philosophers. Needless to say, the platonic philosophers, not the sophisticated ones. What does it illustrate? Well, knowledge requires you to leave this world, to turn your intellect away from the physical, to reorient your whole soul, disposition, and interests to leave the half-real shadow. If you want knowledge, it is not of this world. Another point it illustrates, the crucial and final knowledge required is to reach the form of the good. Until you know that, you cannot organize your knowledge into an understandable vision of reality. And therefore you have no way of knowing how to live a proper life, because you don't know what is the good, what is it all for, what is the purpose of it. You can't make sense of anything without that knowledge of the good, and therefore your actions are hit and miss, chance, self-defeating, self-destructive. And notice also it is a painful process. It's difficult because, and that was the analogy in the myth of the cave, was the constant physical pain you had in adjusting to the light. It's difficult because to grasp it you have to turn away from everything familiar, from the senses, from the physical, and achieve a vision which takes, as I mentioned, years and years of more and more abstract preparation. The result is that most men never reach it. They never learn about even the world of forms, let alone the form of the good. They spend their lives in the shadows. Now I ask you to exercise your ingenuity, if you think it takes that, and predict what are the political implications of this viewpoint. Just ask yourself if the crucial knowledge needed to live is painful, difficult, incommunicative. If you require a mystical insight that only a very few will ever be able to achieve, then who is going to be qualified to tell men how to live their lives and govern their political affairs? Only those few. This is the epistemological base of Plato's politics, which we will get to later this evening. And it is the first instance of an invariable law of philosophy. Mysticism leads to dictatorship. As to people who oppose Plato, going back now to the meaning of the myth of the cave, if you were to say to Plato, well, I don't believe in your world of forms. I believe in physical objects that I can see and hear and taste and so on, and that's what I take as real. A true Platonist will say that answer gives away everything. That answer is the proof that you are one of the ignorant masses caught in the cave, and that it is therefore hopeless to try to reason with you. But you don't have to worry, because the sojourner from the cave promises to come back down and give you all the guidance you need. Now that is the essence of Plato's metaphysics and epistemology. We want now to turn to his ethics, but before we do it systematically, you can see from the myth of the cave itself the general direction or tendency that Plato's ethics will take. What will be the goal of the moral man? Obviously, to escape from the cave, to reach the higher world of beauty, truth, and sunlight. His attitude to the cave, to this world in other words, will be disdain, dislike, yearning to get out. Now how in actual life does a man escape from this world? His body is doomed to remain in this world. It's physical, it's part of the sensible world. Only his soul can go to the world of thoughts, and this it does when the man dies, at death, and consequently the ultimate goal of such an ethics is death. In other words, escape from this world, the freeing of the soul from the body, the shadows, and the imperfections. Now you may think I am reading something into Plato, implicitly criticizing him from the framework of the objectivist ethics, so I quote you a passage from the Phaedo, quote, this is Socrates speaking, representing Plato's view, quote, ordinary people seem not to realize that those who really apply themselves in the right way to philosophy are directly and of their own accord preparing themselves for dying and death. If this is true and they have actually been looking forward to death all their lives, it would of course be absurd to be troubled when the thing comes for which they have so long been preparing and looking forward. If a man has trained himself throughout his life to live in a state as close as possible to death, would it not be ridiculous for him to be distressed when death comes to him? It is a fact that true philosophers make dying their profession, unquote. Now you may ask, well why not commit suicide? And Plato's answer is the same as the Orphics before him and the Christians after him. They create this world, this other world, which they regard as magnificent, but after all if you exhort your followers to suicide, it is very difficult to have a mass movement. So suicide is prohibited. God giveth, God taketh away is the idea. Nevertheless, what you can do during life is free the soul as much as possible from domination of the body. In other words, live an ascetic life. Here's a brief excerpt from the Fido dialogue between Socrates and another philosopher. Do you think that it is right for a philosopher to concern himself with the so-called pleasures connected with food and drink? Certainly not, Socrates. What about sexual pleasures? No, not at all. And what about the other attentions that we pay to our bodies? Do you think that a philosopher attaches any importance to them? I mean things like providing himself with smart clothes and shoes and other bodily ornaments. Do you think that he values them or despises them, insofar as there is no real necessity for him to go in for that sort of thing? Answer, I think the true philosopher despises them. Then it is your opinion in general that a man of this kind is not concerned with the body but keeps his attention directed as much as he can away from it and toward the soul? Answer, yes it is. So it is clear in the case of physical pleasures that the philosopher frees his soul from association with the body so far as is possible to a greater extent than other men, unquote, etc. Now you know that Plato has a legion of followers on this point, stretching all the way from the early Christians to the late hippies. In their anti-materialism, right down to their own body and to the clothes they wear, their basic attitude is Platonism. They do not however apply it to sex in the way that Plato recommended and I should say in Plato's behalf he was much neater. And I should point out that the hippies do it on the same metaphysical, metaphysical epistemological basis Plato, from whom they got it, although they got it directly from the comic strips but ultimately from Plato. Namely the idea that there is another reality which transcends this one and that you grasp it by a mystic vision. However they represent a new modern version of mysticism in which the key to the mystic vision is not 40 years of higher mathematics but one dose of LSD. That however is simply the transformation of mathematics into chemistry as the supreme key that does not alter the philosophy involved. Now you see here there is an exact parallel which Plato explicitly draws in his epistemology and his ethics. In epistemology the bodily senses deceive us, true knowledge comes from pure reason itself, severed from the physical. Well just as the bodily senses deceive us in epistemology, so the bodily desires corrupt us in ethics and true virtue is thus being anti-physical. So both knowledge and virtue require leaving the cave, in other words leaving this world. And you see here the obvious Pythagorean Orphic influence on Plato. I remind you again Plato is a Greek and he is not fully consistent. Certain of his dialogues are much more this worldly insofar as he writes qua Greek. Greek was simply too healthy a civilization to produce anything such as the aberrations which came when Christianity took over. And you will see that when the time comes in this course. How are we supposed to have grasped the universals prior to birth? By what means? Seems to be the idea that we saw the perfect man but how do you see freedom? Well a perfectly good question, only you make a certain concession here. You think well it's easy enough to see the perfect man but remember the perfect man is madness and that's not physical. It doesn't have a head, it just has headness and so on. So it's a perfectly good question, there's no answer. All that Plato's epistemology does is move the question of how you acquire knowledge of concepts back one step. You can't get them in this life, you got them in another. But then the question is how did you get them in the other? And Plato simply says you got them somehow. Now this is always true of reversions to supernaturalism. The same exact principle applies to the question where did the world come from? And people think well we got an answer if we say it came from God. But then of course the question is where did God come from? And you're back where you start. Supernaturalism explains nothing and therefore Plato has commonly been criticized on the grounds that his theory does not answer the question it's designed to answer. How does Plato account for the fact that particular men are not omniscient, that all men are born knowing everything? Well partly because the knowledge is born in your unconscious and therefore a complex process is required to dig it out. It doesn't simply surface by itself. That's Plato's epistemology, how you acquire this knowledge and make it real. But the point is a complex process is required. It doesn't just pop up by itself. And it's a process of such a nature that if you are interested in the physical world and physical pleasure you simply won't perform it. You'll turn away from that process and instead concentrate on money and sex and things like that and so you'll remain ignorant all your life. But if you follow Plato's epistemology of ethics you will one day hit the jackpot in no effort. You can't miss it. The question by the way for those who didn't hear, how does a philosopher know he's seeing the ultimate form when he actually doesn't? Well the answer of the whole Platonic tradition is the experience you have when you get it is so overwhelming, so revolutionary, so soul-penetrating that no one could possibly be mistaken. Now you know the, for instance, the Hollywood movies about when you're in love bells go off. Well that is nothing compared to what goes off when you hit the form of the good. Yes I agree with Plato's distinction between belief and knowledge. Although not the Platonic interpretation of that as reflecting two different dimensions. I agree that you have to know why in order to call something knowledge. You have to be able to prove that it must be so on the basis of fact. It does not however follow that the Greeks couldn't be certain that the sun would rise or that man was mortal because the question is what do you take as a proof? What do you take as an answer to the question of why? And here the crucial objectivist point is knowledge is contextual. You can be certain within the context of a certain amount of knowledge and proceed to expand your knowledge accordingly when more evidence comes in. You do not have to know the latest discoveries from biology to know that man is mortal. You do not have to know the Newtonian theory of the heavens in order to know that the sun will rise tomorrow. Now if you have further questions on the conditions of certainty and of the nature of an explanation, in part I will cover them when I present Aristotle's view of explanation and in part I will say something on this subject in lecture 12 in connection with the general subject of how can you attain certainty. Does Plato hold that there are no degrees of truth, only no knowledge or omniscience? Ultimately he does hold that. Either you know everything or you know nothing. If you use knowledge in its strict sense, you either know the form of the good or you don't. If you don't, then of course you have a probability, you have hypotheses, you might have whole worked out systems but they're hanging in the air. And in that sense you don't have true knowledge. But of course he makes a distinction between a scientist who wouldn't know the form of the good and yet have an awful lot of accumulated data about the unreal world and an awful lot of probable hypotheses about the forms versus a baby. So in that sense he makes a cognitive distinction of sorts. How does Plato know that the ultimate form is the good not the bad? That's a good question. That's a good question to which there's no answer. The only thing you can say is this. If you are going to be a universal teleologist at all, and of course I tried to indicate the reason for it, it is infinitely healthier to be a platonic type than the opposite type. Now there is the opposite type but again it couldn't have developed until the 19th century and that was Schopenhauer. Schopenhauer holds that everything happens for a wicked purpose. He is what's called a metaphysical pessimist. He believes that the goal of everything is to make life as miserable as possible and that the thing to do therefore is collectively for human beings to sacrifice everything and hopefully extirpate the entire universe. A typically 19th century thought. Compared to that Plato is just a benevolent life lover.