 Hi, I'm Peter Adamson and you're listening to the History of Philosophy podcast, brought to you with the support of King's College London and the Leverhulme Trust, online at www.historyoffilosophy.net. Today's episode, Ain't No Sunshine, the cave allegory of Plato's Republic. When we last left our hero Socrates midway through the Republic, he had finished describing the city of perfect justice. In this city, there would be three classes of citizens, the true Guardians, the auxiliary soldiers and the craftsmen. The Guardians would rule, just as reason rules in the best soul. The other parties to the discussion, Glaucon and Adeimantus, have accepted not only this, but some astonishing proposals, such as the communal sharing of property and children amongst the Guardians, and the acceptance that women too can be Guardians. Now Socrates promises a final, yet more astonishing claim. He wants to show how the ideal city could, at least in principle, actually come into existence. It could only happen, says Socrates, if the rulers of the city were philosophers. It's fitting that this most notorious idea in the Republic is illustrated with some of the most famous passages in the Platonic dialogues. These include what must be the most popular image in all of ancient philosophy, the allegory of the cave. Also found in this stretch of the Republic are two more well-known images, the divided line and the comparison between the sun and the form of the good. Clearly this part of the Republic would feature heavily in any compilation of Plato's greatest hits. And it's no surprise that he's reaching for his best material here, since the view Socrates is presenting is both crucial and, let's face it, hard to swallow. Socrates himself draws attention to this, saying that he expects to be drowned by a wave of objections or plain old ridicule when he says that philosophers should rule. After all, philosophers, then as now, were hardly seen as potential politicians. Admittedly, we've seen philosophers occasionally coming into contact with political power, for instance Anaxagoras associating with Pericles, or Plato himself going to Syracuse. But more typically, philosophers were seen as amusing, detached intellectuals, just as they are today. Think back to Aristophanes' portrayal of Socrates in The Clouds, and you'll get the idea. So when Socrates produces the cave allegory and these other famous images, he is trying to explain why the philosophers should rule in the city. But he's also trying to explain why in our own far-from-ideal societies the proposal seems absurd. To understand his argument, we should remember that Socrates is thinking of a successful philosopher. This will be a man or woman who has achieved knowledge, not someone who, like Socrates himself, knows only that he knows nothing. Indeed, Socrates tells us who the philosopher is by telling us what knowledge is, and how it compares to belief and ignorance. Knowledge and belief, he says, are both powers, and powers are distinguished by their objects. For instance, sight is the power that concerns visible things, whereas hearing is the power that concerns audible things. So if knowledge and belief are powers, what are their objects? According to Socrates, knowledge is the power that concerns what is, whereas belief is the power that concerns both what is and what is not. Ignorance, meanwhile, only concerns itself with what is not. So what does that mean? Knowledge concerns what is, belief what is and is not. It's apt to remind us of the beginning of Parmenides' poem. And like the poem, this bit of the Republic has provoked puzzlement and comment in equal measure. The most common way of understanding the passage, and one which became popular among Platonists in later antiquity, is that the objects of knowledge are a completely different level or realm of reality, the forms. The forms are separate from physical things in the world around us. These physical items are in turn the things that are and are not, the objects of belief. But why should I admit that a physical thing like a giraffe both is and is not? In fact, what would that even mean? It's not easy to say, though the later ancient Platonists do have a few suggestions. For instance, they connected this idea to the Heraclitian flux theory. Since physical objects are constantly changing, always going from being one thing to being something else, they both are and are not. If you don't like that, you might prefer a more recent interpretation. Socrates means to say that knowledge only is, in the sense that it is always true, whereas belief can be either true or false, and thus concerns both what is and what is not. Ignorance, of course, concerned only what is not, because it is always false. However we should understand Socrates here, it's clear that the philosophers are a very unusual group. Whereas many people love beautiful sights and sounds, for instance, only the philosophers concern themselves with, and love, beauty itself. But does this really sound like a qualification for the job of political ruler? If anything, it seems like the philosopher would have nothing to say about the messy world of politics, with its conflicts and compromises. The philosopher's head will be squarely in the clouds, as Aristophanes said. For Socrates, though, nothing could be further from the truth. After all, the whole point of the Republic is to establish a city governed by perfect justice, so the ruler will have to be the person who grasps the nature of justice. In the first of the series of famous images which now come thick and fast, Socrates describes the situation of a typical Greek city as being like the situation on board a ship. There's a rather stupid ship owner, who represents the people of the city. A crowd of sailors, representing typical politicians and sophists, tries to persuade the ship owner to let them steer the ship, using persuasion, drugs, and wine, or whatever else comes to hand. But the one person on the ship who actually understands navigation, who can steer by the stars, understand the weather, and so on, is disdained by everyone else on board as useless. This is the man who should by rights be the captain, just as the philosopher should by rights be the ruler in the city. So what exactly does the philosopher know which qualifies him or her for political rule, the way the art of navigation qualifies the true captain to steer the ship? Well, clearly justice itself, and apparently beauty itself as well. In short, the philosopher knows about the forms, as we know and love them from an earlier Platonic dialogue, the Phaedo. But now Plato has Socrates say something he didn't say in the Phaedo. Yes, there are forms of justice, beauty, and so on. But there's something even more important, the form of the good. Knowledge of the good will be a kind of capstone to the philosopher's wisdom, because without knowing the nature of goodness, the philosopher will not understand what is good about all the other forms. And here comes another famous image. Socrates compares the form of the good to the sun. Just as the sun makes the visible objects around us visible to sight, so the form of the good renders the other forms intelligible to the soul. Indeed, just as the sun gives growth and nourishment to the things in nature, the form of the good gives being itself to the things known by the soul. In a phrase which will reverberate in centuries to come, the form of the good is said to be beyond being in dignity and power, a kind of super form which gives other forms their goodness and intelligibility. Now I know what you're thinking, and fortunately Glaucon is thinking the same thing. He presses Socrates to explain what in the world he's talking about with this image of the sun. Socrates is happy to oblige, and in his explanation he provides the two final images in this middle part of the republic, the divided line and the allegory of the cave. The image of the divided line is supposed to help us understand this idea that the sun and the form of the good are first causes or principles. The sun, as I said, both makes things visible and helps make the things exist in the first place. In the same way, the good is a kind of first principle for forms. The form of justice could not be what it is without being good, and neither could the form of beauty. So grasping the good will be a kind of key that unlocks for us the understanding of all the forms. It seems to stand as the highest principle in a kind of hierarchy presiding over the forms. The physical things around us in the visible world partake of these forms and thus can be thought of as images of the forms. And at the very bottom of the scale of reality there are images of these images, for instance shadows or reflections of physical things. So to illustrate the theory Socrates asks us to imagine a line cut into two unequal parts, with each part subdivided in the same ratio into two unequal segments. So we have a line with four segments. The lowest segment represents those mere images of physical objects, the shadows and reflections. The next segment represents the physical objects themselves, the things that non-philosophers take to be really real, like giraffes, rocks, and the Eiffel Tower. These two segments together symbolize the whole visible realm. The second, longer part of the line represents what we can know rather than what we can see. It likewise is subdivided into two segments. Here we are expecting Socrates to say that the two higher segments are supposed to stand for the forms and then, at the very top, the form of the good. This isn't quite what he says though. Instead, he says that the first segment represents what he calls hypotheses. These are things we know on the basis of some other, more fundamental principle. Then the final, longest segment of the line represents those fundamental principles, the truths on which all other truths are founded. Socrates gives the example of geometry, but we might be more comfortable with something like a logical or arithmetical system. You have your fundamental axioms, and from these follows the truth of the whole system. But that way of putting it is somewhat misleading, because for Socrates the basic principle will not be something we simply postulate, like an axiom in mathematics. It will be something certainly and unshakably true. This then is the role played by the form of the good. An object of completely certain knowledge in its own right, it grounds all our knowledge and makes that knowledge come out true. And that finally brings us to the cave. Unlike the rather abstract image of the line, the allegory of the cave is extremely concrete. We are to imagine a group of prisoners, chained at the bottom of a cave. Behind them is a wall, and beyond that, a fire. There are more people just behind the wall, carrying puppets. Thanks to the firelight, these puppets cast shadows on the wall in front of the prisoners. The unfortunate prisoners can see nothing but these shadows, and hear nothing but the echoing noises made by the puppeteers. They are radically removed from reality, because they see nothing but shadows of things that aren't even real, namely the puppets. They very seriously engage in completely pointless games, competing to predict and identify the shadows. Of course, the disturbing message is that we are like the chained prisoners, and that the apparently crucial political debates and public affairs of our societies are like the meaningless shadow games played by the prisoners. Now Socrates asks us to imagine what would happen if a prisoner were set free. Wrenched away from their familiar reality of shadows, they would only go kicking and screaming if someone dragged them out into the sunlight. But once they were pulled from the cave, after recovering from their dazzlement, they would finally see reality for what it is. As you've already guessed, this freed prisoner represents the philosopher. Just as the philosopher grasped the forms, using the form of the good as a principle, so the freed prisoner sees the real things outside the cave by the light of the sun. And this explains why philosophers seem useless and otherworldly in our corrupt societies. The philosopher has no interest in the shadow games and secondhand images of normal folk. Meanwhile, these normal folk have no hope of understanding the true reality the philosopher has witnessed. So the prospect for achieving justice in the real world would seem to be rather bleak. We prisoners duped in our world of images will never welcome the philosopher as a ruler. Indeed, Socrates admits that just about the only way a philosopher could get to rule a real city would be by a stroke of great fortune, whereby a philosophically minded person is born to a king and inherits his throne. This isn't very likely of course, but Socrates is happy if he can just suggest a way that the ideal city could come about in principle. But there's another problem. What's in it for the true philosophers? It's clear they would have no interest in descending back into the darkness of the cave. Why plunge again into the cave of shadows when they could stay out in the sunlight? Socrates tackles this problem squarely, admitting that it is not really in the philosopher's interest to rule. But they're not selfish, and they must see that the demand of justice is for them to take command of the city if at all possible. And so it is with regret, but a feeling of duty, that the philosophers of the republic, the true guardians, would become philosopher kings. Ironically, it is those who care nothing for power who should truly hold power. And is it me, or does Plato have a point here? The Allegory of the Cave is one of the most powerful passages in the Platonic Corpus. And at the political level its meaning is clear. It tells us that the philosopher should rule, and also explains the apparent cluelessness of philosophers in defective societies. Speaking as a philosopher who does tend to appear clueless, I can only agree wholeheartedly with that last bit. But what about the other philosophical implications of the allegory? There are two common misconceptions about the cave, which I'd like to clear up before concluding this episode. The first misconception is that the cave allegory commits Plato to some kind of radical separation between our world and the world of forms. This is a widespread assumption about Plato, that he believes in a kind of separate heaven of forms and urges us to ignore the physical world entirely in favor of that other, immaterial world. Aristotle in fact often criticized Plato for holding that the forms are radically separate from the things around us. But if the shadowy cave world is separate from the sunny world outside, it isn't radically separate. You can go from one to the other, after all, as the philosopher does. And remember that the shadows that the prisoners see are shadows of puppets, and the puppets are puppets of the things outside the cave. That shows that there is some kind of connection between the shadows and the real things outside. The shadows are second-hand images of reality, but they are still images of reality. Perhaps then Plato's point is not so much to stress that there are two utterly different realms of objects, physical pseudo-realities on the one hand and real forms on the other. Instead, the point might be to describe two different ways of seeing one and the same reality. We can grasp that reality by means of transitory ill-considered beliefs, or with solid, certified knowledge. Usually, we make do with truths that are mixed generously with falsehoods. But the philosopher's approach demands truth and nothing but the truth. So the radical contrast or separation Plato is making is not so much between two realms, one heavenly and immaterial, the other shadowy and physical, as it is a contrast between knowledge and mere belief. A second misconception about the cave allegory is that Plato is endorsing some kind of mysticism. On this interpretation, the philosopher would grasp truth and reality in a kind of flash of insight upon leaving the cave. The result will be an understanding so deep, so otherworldly, that the philosopher simply cannot explain it to the benighted prisoners down in the cave. It is a knowledge which cannot be put into words. Now admittedly, the idea of turning the eye of the soul from ignorance towards some kind of luminous knowledge does appear in the later Platonic tradition. But when Plato himself talks about turning away from the shadows, he describes an arduous process of education, not a divine flash of revelation. First, the freed prisoner must climb the steep path out of the cave. And even when he escapes, it is not so much the sun that he sees as the things in the world illuminated by the light of the sun. As my colleague M.M. McCabe is fond of pointing out, seeing can be an active, analytical process, more like examining or looking than a flash of insight. And there are good reasons to think that this is what happens when the philosopher escapes from the cave. Think back to the divided line. As we saw, this image tells us that knowledge has a specific kind of structure, according to which first principles guarantee the truth of the rest of the things we know. This is what Plato calls dialectic. Dialectic means the process of making hypotheses, and then discovering the principles that would support those hypotheses as they do in geometry. This doesn't sound particularly mystical. Plato presents knowledge as a complex, analytical process. It also seems that the fruits of such a process could be put into words. When the philosopher goes back into the cave, he's not able to convert the prisoners to the truth just by talking to them, but this isn't because he has nothing to say, that his knowledge is inexpressible or mystical. It's simply because the prisoners would never be able to understand or be convinced by the philosopher's account until they themselves engage in dialectic. Some listeners might be suspicious of the points I've been making towards the end of this episode. They may feel that I'm making Plato less, well, platonic. Surely the whole point of Platonism is that it is an otherworldly philosophy, that there is a separate realm of forms which can be grasped only by direct intuition? Well, Karl Marx famously said that he wasn't a Marxist. And if this is what Platonism is, then for my money, Plato was no Platonist. If you're not convinced yet, please reserve judgment until next week. We'll be looking at the opening section of a dialogue called The Parmenides. There, Plato boldly uses Father Parmenides himself as a spokesman, and puts into his mouth a series of devastating objections to the theory of forms. What is there called the greatest difficulty for the theory highlights the dangers of making the forms radically separate from our world. So at least by the time he wrote The Parmenides, Plato saw that there were potentially devastating objections against this kind of Platonism with its totally separate world of forms. Join me then for the first great critic of Platonism, Plato, next week on The History of Philosophy Without Any Gaps.