Plato's Epistemology

There are two important themes in philosophy that I think are very closely related. They are the study of what knowledge is and isn't, and the study of what does and does not exist. The study of knowledge is called "epistemology," and the study of "being" or "is-ness" is called "ontology." (I don't know why "ontology" isn't called "beingology" or "isology," and I don't know what an "ont" is.) I don't really think that these two issues can ever be fully separated, and I will talk more about this later, once we have talked about Plato 's epistemology, and Plato 's ontology.

Before I get started on the lecture, I want to emphasize that Socrates and Plato had very different ideas about knowledge, and it is very important not to confuse the two. Socrates gave a descriptive account of knowledge, so he really didn't have a theory of knowledge. Plato, as we shall see, had an actual theory. One way of explaining the difference between the two accounts of knowledge, is to say that Socrates gave us a description of knowledge so that we would be able to recognize real knowledge when we saw it. Plato, on the other hand, has a theory about what we are looking at, when we contemplate knowledge. If that doesn't make sense to you yet, keep the question in the back of your mind as you read the below. In any event, make sure that you do not confuse the two accounts of knowledge on the next exam. Answer in questions about one account by giving information about the other account will be wrong, and will not get you any points.

Epistemology

There are two big questions in epistemology. The first is, what is knowledge? The second is, what is truth? Socrates really did not answer these questions. To understand this, and to see where you are at this moment in the reading, imagine that you are curious about an electronic device you have just heard of called a "gorplatz." You don't know what this thing looks like, and you have no idea what it does, or how it does it. Now imagine that Socrates and Plato run a gadget store, and that they are answer your inquiry "what is a gorplatz?" The same way they answer the question "what is knowledge?" First, Socrates gives you an elaborate and highly detailed explanation of what a gorplatz looks like, how to tell a good one from a bad one, and tells you where in the store to look for one. Plato is utterly silent at this point. So you go to the right place, find something that fits the description (nothing is labeled here), and begin playing with it to see if it fits Socrates 's description of a good gorplatz. While you are playing with it, you notice that a display on the front changes as you move it up and down. After a little thought, you realize that the gorplatz tells you the distance between itself and the center of the Earth. Extremely excited, you rush back to Socrates and ask him "what is this thing?" He replies, "it's a gorplatz, it tells you the distance between it and the center of the Earth. "No-no," you say. "I mean, what's inside the casing? What is the thing in here that tells the distance between itself and the center of the Earth?" Socrates is silent. He has never thought about that. Plato, on the other hand, steps up and tells you that the gorplatz contains a receiver that collects information from GPS satellites translates it into altitude readings, adds a correction for the fact that the Earth is thicker the equator, and displays the result. In terms of epistemology, Socrates told us what knowledge was like,. Plato is trying to tell us how knowledge works.

You will recall that I told you that Socrates created a descriptive account of knowledge, and basically left the task of creating a theory to Plato. Another thing that happens in philosophy is that philosophers try to break problems down into very small chunks and see if they can solve the first chunk all on its own. Breaking down a problem into manageable bits is usually a very good idea. It doesn't always work, but when it fails, it usually fails in such a way as to tell us interesting things. In my view, Plato tried to solve the problem of knowledge, while ignoring the issue of truth. This might turn out to be a problem later, or it might not. For now, I want you to keep it in the back of your mind that Plato is developing a theory of knowledge, while not really thinking about the definition of truth. Well, to be honest, you can understand this section without worrying about the difference between knowledge and truth. If this question is boring, confusing, or makes your head hurt, you don't have to worry about it right now.

Another issue you don't necessarily have to worry about is the issue of critical reading. In the text, Donald Palmer uses the term "give the logos." I'm really not sure what he means by this. At one point, he says that to "give the logos" for a belief is to "justify" that belief. This seems fine to me, except that at another point, Palmer defines the term "give the logos" as something like "give a complete account of everything that is known about the object in question," which I think is very different from justifying a belief. The point I want to make here is that, if you are confused about the meaning of the term "give the logos," that's actually a good sign, because it proves that you're paying attention, and you're thinking about the material. In my view, you are confused because the reading is confusing. So when you meet any kind of text book, and you come across material that is confusing to you, it could of course be that you're just not getting it, but it could also be that the writer has failed to make himself clear, or he doesn't know what he's talking about.

Which brings me to what is called the principle of charity. Charity, in philosophical discourse, means trying to make the best sense out of other people's work. If we are to be charitable towards Plato, and there are two possible interpretations of some part of his philosophy, charity says we should take the best one. To put it another way, we should never interpret a writer as saying something stupid, if we can possibly find a way to interpret his words as saying something sensible. I think interpreting Plato as requiring people to "give the logos" to justify any knowledge claim is unnecessarily complicated, and makes Plato look bad unnecessarily. I'll come back to this idea in the next essay.

Now, finally, on to Plato's theory of knowledge. It's going to seem like a very simple, obvious theory. But it has a flaw, which I will discuss in the next essay. You don't have to think about it right now, but if you'd like to, you can read this with your eyes open for a problem. Or not, that's fine too.

Plato's theory of knowledge is that knowledge is Justified True Belief. That is, Plato says that you have knowledge if and only if 1. You have a belief, 2. You have justification for that belief and, 3. That belief is true. Plato's theory thus says that knowledge has three elements. Not two. Not four. (Five is right out!) Three. So if it turned out that one of these elements were such that nobody could ever actually get it, Plato's theory would turn out to say that nobody could ever have any knowledge, which would be a silly result, making Plato 's theory a silly theory.

The belief part of the theory is pretty simple. Belief is just a matter of thinking that something is true, and I don't really have anything interesting to say about that. Justification is a bit more interesting. When would you say a belief is justified? My personal definition of "justification" is that a belief is justified when it is the only even remotely reasonable explanation for all the available evidence. Truth is, well, let's just say, for now, that truth is truth. (Those students who are practicing critical reading might find themselves suspicious over the fact that I have not given a very clear definition of "truth." Other students are probably wishing I would stop dropping hints, and get on with the lecture.)

Here's an example. Did you ever hear of the Tacoma Narrows Bridge? (YouTube probably has a video.) Anyway, the Tacoma Narrows Bridge was a very long, very elegant bridge over a river in Washington. And very soon after it was built, it fell down in a very interesting way. Now, let us say that before the bridge fell down, the following people all had the belief that the bridge would stay up for at least 50 years. Freddie Faithful believes the bridge will stay up because he has faith that it will. Angela Angelsflight believes the bridge will stay up because she believes that it is held up in the air by angels. Engineer Ed believes that the bridge will stay up because he knows all the principles of solid bridge building, and has verified that the Tacoma Narrows Bridge has been built according to these principles. According to Plato 's theory of knowledge, none of these people had knowledge. Freddie Faithful clearly did not have knowledge because his belief did not have any justification whatsoever. Having faith that something will happen is no different from simply believing that it will happen. Angela Angelsflight had any "justification," but it was a silly one, so it really doesn't count as a justification at all. Engineer Ed did have something that most people would think would be a justification, but his belief wasn't true, was it? So he had a justified belief, but not a justified true belief, so by Plato 's reasoning, he didn't have knowledge.

Now let's consider three people who believed that the bridge would fall down. Fanny Faithful believed that the bridge would fall down because she had faith that it would fall down. Desmond Demonology had a theory that a division of demons would attack the bridge, overcome Angela's angels, bite through the suspension cables, and send the bridge crashing down. And finally, physicist Philippa believes the bridge will fall because she believes that a steady wind blowing through the Tacoma Narrows will set up a standing wave in the resonant frequency of the bridge, causing it to oscillate in progressively wider arcs, eventually over straining its cables. (Philippa is fictional.) Now, although each of these people has a true belief, only Philippa has a justification for her true belief, and so only Philippa has knowledge according to Plato 's definition of knowledge. Philippa believed the bridge would fall, she had a justification for the belief, and the belief was true.

Now, when you come to discuss Plato 's theory of knowledge in the exam, you had better be able to explain how belief, justification and truth are supposedly different from each other. Define each one individually, and make it clear how each is supposed to be a different thing. If I ask you to explain Plato 's theory of knowledge, that is what I will be looking for. (Any other comments you may care to make will be welcome, but they are not required.)

Ontology.

Plato's "simile" of the line is sometimes thought to be part of Plato's epistemology, as well as his ontology, but I don't think so. I think that Plato's "simile of the line" is basically an explanation of his ontology, with no significant epistemological implications. What I mean by this is that a complete understanding of the simile of the line will not require us to make any changes in our understanding of Plato's theory of knowledge as justified true belief. No matter what happens as we discuss the simile of the line, we will never come across a reason to change our minds about how we interpret Plato's epistemology. In my view, the simile of the line isn't really about epistemology at all! (Okay, I know that made no sense to anyone. I'll try to make it clear later, but if you don't get it, don't worry about it.)

Well: here's a sort of thought experiment, if you're interested. Take two blank.pieces of paper. Draw lines across each piece of paper as though it were one side of the simile of the line. Write "epistemology" at the top of one piece of paper, and "ontology" at the top of the other. The first piece of paper now represents the left side of the line, and the second piece of paper now represents the right side of the line. Now, try to fill in, in your own words, the left, "epistemology" side of the line without making any reference to things on the other side. Try to define "imaging" without saying anything about what an "image" is, and so on. Once you have tried this for awhile, see if you can't do it the other way. Try to fill in the ontological side of the line without any reference to epistemology. Can you define "image," without saying anything about what kind of knowledge, knowledge of images is?

I'm not even going to try to talk about the epistemological side until I've completely laid out the ontological side. If you think you can lay out a complete explanation of the epistemological side without saying anything about what kinds of things can exist, please e-mail me and tell me how you did it.

I find the easiest way to explain Plato's ontology is to start at the bottom. The first and worst category of being is "images." Images are representations. They could be representations of real things, as in pictures or statues of real people, or they could be representations of imagining things, like movies about Mickey Mouse. They are "real" in the sense that you can see, or hear, or touch the image, but they are unreal in the sense that they are only representations of things. Images are incredibly unstable. They can disappear in moments, never to be seen again. Images are the lowest order of being for another reason. They are the lowest order of being because they are the most dependent kind of being. Images are always representations of things, or representations of distortions of things, or representations of combinations of parts of things. A realistic drawing of a mouse relies on the existence of real mice to depict. Mickey Mouse is a highly distorted image of a mouse, and so still depends on the existence of real mice. In fact, Mickey Mouse is a distorted combination of mouse and person, and so still depends on the existence of mice and people. For Plato, images are more or less distorted representations of other things, and thus have very little reality of their own. The fact that we can imaginatively create a representation of a mouse-person like Mickey Mouse is a weakness from Plato's point of view. Images can represent things that don't actually exist, and so they are highly unreliable. Unreliability is a bad thing, and so images are not a very valuable part of reality.

Slightly more real, and therefore more valuable, are "sensible objects." Sensible objects are objects that can be detected by the senses. (Duh.) This category includes absolutely everything you can see, hear, touch, taste, smell or otherwise detect with your senses. They are more real than images, because images depend on them, and they do not depend on images. They are more stable than images, because they have more tendency to stick around, and they appear in recognizable patterns, so that ones that disappear are usually replaced by similar objects. The clouds of yesterday are gone, but they might be replaced by new clouds today. The trees of a hundred years ago might be gone, but they tend to be replaced by new trees. Modern people tend to think that things that can be directly experienced are the most real things, but Plato is just getting started. For Plato, sensible objects are more real than images, because images are dependent upon sensible objects.

But sensible objects are themselves a dependent kind of being, because they depend on the laws of nature for their existence. Think about how the shapes and workings of sensible objects depend upon the laws of nature. Why do rivers flow the way they do? It's because water evaporates from the oceans, is transported in the air, and condenses again over land to fall as rain. That rain flows downhill, eroding out channels for itself as it does. These channels converge, and eventually become rivers. So the existence of rivers depends on the physics of evaporation, condensation, uplift of mountains, and erosion. Every existing sensible object can be given an explanation that consists of laws of nature apply to certain initial conditions. Without the natural laws, nothing would have the shape it does. With different natural laws, things would have different shapes and workings. The existence of our world as the kind of world it is depends precisely on the existence of certain laws of nature, and therefore, for Plato, the laws of nature of a different, and higher order of being than sensible objects.

Plato does not stop with the physical laws. He believes them to be yet another form of dependent being. He believes that the existence of natural laws would not be possible if there was not something higher than them for them to depend on. Plato believed that the natural laws were dependent upon what he called the "forms." (This is what we call a "metaphysical" belief, because it is a belief that there is something higher and more real than the physical world.) The forms, Plato believed, were all aspects of an ultimate reality that he called "The Good." Think about all the really good things in the world. Beauty is good, and so there is a form of beauty. Justice is good, and so there is a form of justice. Courage is good, and so there is a form of courage. Plato thought that piety was good, and so he thought that was a form of piety. The forms were the highest kinds of reality, short of The Good itself. The forms depended on The Good, natural laws depended on the forms, sensible objects depended on natural laws, and images depended upon sensible objects. A nice, orderly, arrangement of reality.

Now here is where modern thinkers might think that Plato has gone overboard, because he invents a category of being that modern thinkers don't think is necessary. These ideas seem weird to us, but they didn't seem weird to Plato's contemporaries. It might have been that people in Plato's time were still very comfortable with the idea of the existence of invisible, intangible entities that controlled everything. But it might also have been that, in Plato's time, logic itself was not developed well enough to allow people to clearly see that Plato's forms were not logically supported. Indeed, Plato was one of the people who developed philosophy, and so if it is apparent to us that Plato's forms are a logically unsupportable hypothesis, our very ability to see such things is due in part to the work done by Plato.

Plato, in fact, thought he had very good reasons to believe in the existence of the forms and The Good. First, in common with other Greek thinkers of his day, he thought that must be some one singular thing that lay behind everything else. Natural laws were multiple and diverse, and so they could not be this one thing. Second, in common with many thinkers throughout history, Plato thought that moral categories were more important than physical categories. The most important things in the universe had to exist somehow, and it seemed natural to put them in at the top of his ontology. With that in place, Plato could see The Good as an ultimate, unifying principle of reality, more real than the forces, objects and images it organized. In short, Plato system make perfect sense to Plato, and it also make perfect sense to just about everybody who knew about it at the time.

Remember my question about the relationship between ontology and epistemology in Plato's simile of the line? Did I have to say anything at all about epistemology as I was describing Plato's ontology? No I didn't! Well, now I'm going to fully explain the epistemological part of the simile of the line, and it is going to be unbelievably easy. First, the lowest and least important kind of knowledge, called "imaging," is justified true belief about images. This is a pretty worthless kind of knowledge, because it is knowledge of pictures of things that might not even exist. Second, the only slightly higher and more important kind of knowledge that comes just above imaging is called "belief," and consists of justified true belief about sensible objects. It's better than knowledge of images, but only just. In fact, these two categories of knowledge are both categories of knowledge of things that are so unimportant that we don't even call knowledge of them "knowledge." That word is reserved for knowledge of more important things. Knowledge of sensible objects and images is contemptuously referred to as "opinion." When we reach the category of natural laws, we are finally getting into stuff that can be called "knowledge." Justified true belief of natural laws, is a pretty high and important kind of knowledge. Not as important as knowledge of the forms, or knowledge of The Good, but much better than that other stuff. The top two categories of justified true belief are so important that Plato reserves the word "knowledge," for knowledge of this stuff.

Now, imagine trying to explain these various epistemological categories without making any reference to the ontological categories on the other side of the line. I can't imagine succeeding, can you?

Another way to look at Plato's hierarchy of knowledge is to think about the kind of reasoning necessary to generate each kind of knowledge. Knowledge of images is easy to generate. Just look at the images presented to you. Knowledge of sensible objects is more difficult, because it involves careful observation of the world. Knowledge of natural laws is even more difficult, because it requires serious thinking about the patterns we find occurring in that natural world, and serious thinking about what kinds of laws are necessary to explain those patterns. Knowledge of the forms and of The Good is the most difficult of all, because it requires a kind of thinking that can see beyond even the natural patterns of the world, to discern the nature of ultimate reality. Consequently, Plato values contemplative philosophy above all other forms of knowledge production.

I'll stop here. You will notice that I have not given much in the way of argument for Plato's beliefs, nor have I applied much in the way of critical thinking to Plato's epistemology and ontology. I'll do that next time, under the general heading of philosophical criticism. For now, all I really want you to do is to understand Plato's epistemology, and his ontology as a completely and clearly as you can. That will be quite hard enough.

Study Questions

What are the big questions of epistemology?
What is the name for Plato's style of epistemology?
What is Plato's first requirement for a claim to be knowledge?
If you believe something very, very strongly, does that make it knowledge?
What is Plato's second requirement for a claim to be knowledge?
Is something knowledge if it's true, but I believe it for a silly reason?
What does it mean to "give the Logos" for something? (This will turn out to be a tricky question later.)
In the simile of the line, what are the two things that we can have knowledge of?
In the simile of the line, what are the two kinds of things that we can only have opinions about?
Why is the shadow of a tree less real than the tree itself?
What is it to be in a state of imagination? What are the objects of imagination?
What is it to be in a state of belief? What are the objects of belief?

Thinky Questions

The thing to remember at this point is that we are studying theories that may very well turn out to be wrong. In particular, the argument for innate ideas will turn out to be a pretty crappy argument, and we will discuss what's wrong with it at the end of this unit. However, criticism of Plato's theory of knowledge as Justified True Belief will be deferred until next week. My discussion of that theory this week will completely ignore all potential problems. This basically means that the theory does have problems, and I am ignoring those problems at this time. So, if you see what you think is a potential problem with the theory, make a note of it for next week.

Make sure you do the prequiz for this week, as it will test your understanding of the difference between "justification," "truth" and "belief" in Plato's theory.

Argument for Innate Ideas

As part of this week's "lecture," I will explain, discuss and criticize Plato's argument for innate ideas (the slave boy example). Since the criticism of the slave boy example is fairly simple, I'm going to do it before tackling the deeper issue of dependency in Plato's simile of the line.

I want you to assume that Plato could be absolutely certain that the slave had not studied mathematics. This is for two reasons. The first reason is that it would have been relatively simple for Plato to make absolutely certain that the slave did not know mathematics. Generally, Greeks would know where their slaves came from, particularly the young ones who were usually born in slavery. Although some slaves were educated, the vast majority of them were used exclusively for manual labor, and so it is very unlikely that any master would waste money educating a slave. Second, criticizing the example is much more interesting if we assume that the slave did not cheat.

The slave boy argument depends crucially on the following claims.

1. Socrates made no statements to the slave. Instead, he merely asked questions. Based on this, Plato argues that the slave simply could not have gotten the solution from Socrates because questions do not convey information, and Socrates only asked questions.

2. The slave had not previously studied mathematics, and no one had given him the solution to the problem before he met Socrates and Plato in the garden. (We are assuming that this is true.)

3. There were only two ways that the slave could come up with the answer. Either someone told it to him, or it was already installed in his mind before he was born.

4. At the end of the questioning process, in which Socrates did not tell the slave anything, the slave knew the answer.

I want you to look very closely at claim number three.
1. Can you think of another way the slave could've come up with the answer?
2. If you can, what does that do to Plato's argument?

The Simile of the Line

The deepest question I have for this week concerns the issue of dependency (or "direction of fit") in the similie of the line.

Before we get to that, though, here's an easier "warm-up" question.

Simile?:
Is the "simile of the line" really a similie?
Is Plato's philosophical system really like a line?
Does Plato make any comparisons in this "simile?"
Does Plato say that any part of his system is like a divided line?
Why would they call it a simile if it isn't one?
What does this tell us about names?

If you've figured out what's wrong with the name "simile of the line," and why it irritates me, you're ready for the harder task.

In the so-called "simile" of the line, we find Plato's epistemology stacked up on one side of the line and Plato's ontology stacked up on the other. That is, he organizes all his different types of knowledge on one side of the line, and all his different kinds of being on the other. The question I want to ask you is, which side of the line is primary here? Does Plato's epistemology control his ontology, does his ontology control his epistemology, or are they independent?

If Plato's epistemology controls his ontology, then the structure of Plato's epistemology will determine the structure of his ontology. (In this case we would say that Plato's ontology is dependent on his epistemology, or that his ontology must fit his epistemology.)

If Plato's ontology controls his epistemology, then the structure of Plato's ontology will determine the structure of his ontology. (In this case we would say that is epistemology is dependent on his ontology, or that his epistemology must fit his ontology.)

If they are independent, then neither structure determines the other. (In this case, we would say that neither of them is dependent on the other, and that there is no direction of fit.

I would like you to take a couple of minutes and think about whether there is a dependency relationship between the two sides of the line. Once you have taken a shot at figuring it out without help, go on and do the following exercise.

The way to figure out if there is a dependency relationship between two topics is to see whether or not they can be discussed independently. For instance, if Plato's ontology is dependent on his epistemology, then it will be impossible to give a coherent discussion of Plato's ontology without constantly referring to his epistemology. If his ontology is not dependent on his epistemology,
then it can be easily discussed all on its own, without any reference to epistemology.

What I want you to do to determine the direction of fit, if any, between these two topics, is to try to discuss them independently.

First, try to give a coherent account of Plato's epistemology without even mentioning any part of his ontology. If you can coherently discuss Plato's epistemology without making any reference to any of his ontological categories, then his epistemology is independent of his ontology. If you can't do that, then his epistemology is dependent on his ontology.

Second, try to give a coherent account of Plato's ontology without even mentioning any part of his epistemology. If his ontology can be discussed without mentioning his epistemology, then it's independent of that epistemology. If you can't, it's dependent.

Plato's Epistemology

Epistemology

Ontology.

Study Questions

Thinky Questions

More Study Questions