[reposted December 20, 2002] afterword to lecture
LTHOUGH the notion of a Form is important to Plato's theory, it is difficult to understand what these Forms are supposed to be and why Plato is convinced they exist. So I'll try, first, to help you make sense out of the doctrine of the Forms. Then I will try to show that this abstract doctrine is responsible for some concrete implications.
A Plato comes to his view of the Forms from two premises: first, knowledge cannot come through the senses; and, secondly, we do nevertheless manage to know things—in mathematics, for example. From that, he concludes that there is something beyond the world of the senses of which we have knowledge.
Let's review Plato's reasons for denying that knowledge can come through the senses. In the first place, Plato claims that because material things are constantly changing[1] and "fluctuating,"[2] they are not possible objects of knowledge. Since I find these facts puzzling[3] as reasons for denying that we can gain knowledge of material things, I will pass on to others.
Plato notices that not only do the things we perceive change, but so do the circumstances in which we perceive them. The apparent shade of color of a wall varies with one's vantage-point. The strength, quality, and position of the light source will also affect a thing's appearance, as will the states of one's sense-organs, which are constantly changing as well. If my left hand has been grasping a cup of hot coffee while my right hand has been clutching a cold beer, and I—unaccountably—then put both hands in a bowl of lukewarm water, the water will feel cold to the left hand and warm to the right hand.[4] Moreover, things must often seem different to me than they do to you—for your perceptual circumstances and the states of your perceptual organs are rarely the same as mine. We are also liable to be taken in by illusions, our initial judgments are often influenced by our expectations and biases,[5] and we are subject to states of dreaming and, sometimes, hallucination. As a result, Plato supposes that we can never gain knowledge through the senses: with the competing variety of appearances, there is no sure way to distinguish the supposedly true appearance of a thing from its false appearances.
Plato asserts that knowledge is infallible.[6] One thing Plato means by this is that if there is the slightest possibility[7] of my being mistaken about some belief, then I don't know it to be true. Yet, given the nature of the sensory world, the possibility of my being mistaken seems always present: no matter how careful I am in my observations, there always seems to be some chance that I am wrong. Therefore, it is a world about which one can have mere opinions.
In our practical affairs, as Plato notes, we try to get around these problems by devising and using methods of measurement and calculation:[8] since the carpenter recognizes that the board might seem to be a different size to him now than it will later, and might seem different to him than to his apprentice, he gets out a yardstick and measures it. And in his construction of a house he applies what he knows about geometry. Yet such uses of mathematics and geometry must be quite "rough and ready" on Plato's view. When the carpenter judges the board against the yardstick, he is nevertheless relying on his sensory perception of both. In addition, neither the yardstick nor the board can be perfectly straight, and no triangular support can ever be a perfect triangle: it will be a matter of coincidence if a protractor appears to show that its internal angles sum to exactly 180 degrees. It seems, then, that when we apply mathematics and geometry to the material world, we make judgments which are no longer precise[9] and exact, but approximate[10] and ambiguous.
Now consider the mathematical and geometrical truths which we thus use: how did we, or, our teachers, arrive at them? We can exclude one answer at once: it seems clear that mathematical knowledge cannot have come through the senses. Mathematical truths cannot be mere generalizations of what we have observed through our senses because in that case they would not be necessary truths but, at best, rough rules of thumb. Indeed, we confidently deny the reliability of our senses on those very occasions when they contradict the truths of mathematics: imagine a careful scientist placing two cells on a slide, and then placing three more cells on the slide, and afterwards examining the slide under the microscope; if he now observes more than five cells he will conclude that he must have counted wrong, or that some of the cells must, immodestly, have reproduced, or that something else must have happened. The one alternative which no scientist will seriously consider is that two cells plus three cells does not always equal five cells. If the mathematical truth had been a mere generalization from experience, however, such an episode of a careful scientist's counting more than five cells would have been evidence that two plus three sometimes does not equal five. But obviously it is not. We must, then, know the truths of mathematics independently of sense experience.[11] Unlike an empirical generalization, a mathematical truth cannot be refuted by experience; our knowledge of its truth does not depend upon our perspective or the state of our sensory organs or on the ambiguities of how things appear to our eyes.[12]
To understand the kinds of thing we find in the material world, we need to separate their essential characteristics from their accidental features and superficial appearances. Sensory perception attends merely to a thing's superficial appearance,[13] and is therefore worthless for comprehending the world. To understand a thing we must use reason; and when we reason, we are, at least implicitly, dealing with the Forms
The Forms are required not only to comprehend the material world, but even to understand language itself. When we speak of "two" things, or of items of "equal" length, for example, we use meaningful terms; and since you and I use these common words with the same meaning, they must refer to some one thing with which we are both acquainted. (Notice that an idea in a person's mind won't serve to fix a common meaning of a word, since other people who cannot be acquainted with the contents of his mind can nevertheless understand the word.) We suppose that children come to understand a common noun by being presented with the thing to which the name refers;[14] it seems that a child learns the meaning of "triangle" by being presented with a cardboard triangle, ala Sesame Street. But as we have already noted, a genuine triangle is never presented to the eyes; at best, we present to the eyes approximations to triangles which remind a person of a genuine triangle only if he is already acquainted with one.[15] And since children do learn what the word "triangle" means, they must already have been exposed to a genuine triangle. And since they cannot have been acquainted with a genuine triangle through sense perception, it must have taken place wholly apart from the senses.[16] And this must be true not only of mathematical concepts, but also of concepts such as "yellow," "solid," and "justice."[17] In general, we understand things in the material world by applying to them objective, unambiguous categories; but those categories cannot be identified with anything in the "multiplicity" we perceive through the senses.
So Plato concludes that knowledge must be directed upon perfect Forms which are always the same for everyone. Since our acquaintance of these Forms cannot be distorted by illusion or by the defects of our physical organs, our acquaintance must employ a special sort of perception which avoids those shortcomings. In Plato's theory, then, the Forms serve two functions: first, they are "universals," the properties which things truly described as "yellow," "solid," or "just" must share (at least, in some degree or approximation);[18] and secondly, the Forms are the true paradigms of those common names—the perfect patterns of yellowness, solidity, or justice—with which everyone who understand the concepts must be acquainted.[19]
At this point, as I turn to some consequences of Plato's theory, I need to sketch a rival to his theory. When Plato claims that knowledge does not come through the senses but through the faculty of reason, and that only necessary truths can be known, he articulates a theory called "rationalism." Its rival theory, "empiricism," holds that the senses are the ultimate source of knowledge, and that one can, through the gathering of evidence, acquire knowledge about the material world. Empiricists deny that knowledge is confined to necessary truths, such as "two plus three equals five." Empiricists are often what we might call "fallibilists," holding that there is no fool-proof sign which can show whether one has actually got a piece of knowledge rather than a mere opinion; they hold that extended periods of challenge and defense are needed to test what we suspect is a piece of knowledge. What I should like to suggest to you is that some of the features of Plato's Republic which are often distasteful to a modern reader are distasteful because the features do not make sense within the theory of empiricism—which is tacitly being assumed by the reader; yet they do make sense within Plato's theory of rationalism. Thus, the abstract parts of Plato's theory have concrete implications which cannot plausibly be resisted without examining and challenging his basic theory.
How, then, will an empiricist understand moral judgments? He will not suppose that morality is dictated by a world beyond the senses which establishes necessary rules independently of human decision. Instead, he will say that morality ultimately concerns pleasure and pain. And since pleasure and pain are properties of sensation, the owner of the sensations will normally be in the best position to weigh the advantages to himself of competing plans of life. For that reason, the empiricist will want to allow each individual the utmost latitude in pursuing the good life as he conceives it: both to encourage experimentation in the search for new life plans, and because ultimately, no one is in a better position than the individual to determine how to maximize his pleasure.
Because people can learn only through experience and example which types of action are likely to cause them pleasure or pain, they are subject to mistakes. And so, the empiricist will concede that judging competing plans of life is indeed a matter of opinion; but, he will quickly add—in the words of John Stuart Mill—one's "errors are corrigible. [A person] is capable of rectifying his mistakes by discussion and experience."[20] Because individuals need to learn from the experiences and from the critical scrutiny of others—from "the marketplace of ideas,"— the empiricist is strongly opposed to censorship—which shuts off the free flow of information.
Unlike the rationalists, the empiricist holds that our desires are fundamental in defining our interests. So he recognizes that when the things we prize are scarce, our interests will inevitably clash. And since such conflict is likely to be frequent and destructive, we will need some satisfactory way to avoid or to moderate the conflict. Glaucon expresses, as the received view, that justice is a set of rules expressly created by humans to serve this function.[21] Each person agrees to restrain his own predatory inclinations as the price he must pay to secure the corresponding restraint of others. (I agree not to take your stuff so long as you agree not to take mine.) According to this theory, then, the rules of justice define what is right and wrong because they have been mutually agreed to, not because they follow some pre-existing pattern of justice. —I hope you can see from this sketch of the empiricist view of morality that it is the basis of many of our own political and social institutions.
With his example of Gyges' ring, Plato identifies a huge difficulty for this social contract view:[22] as Adeimantus suggests, supposing that view is correct, it will then be rational for me to abide by our agreement only because if I don't, you will retaliate against me. But imagine that I could receive the benefits of your cooperation without having to restrain my own predatory inclinations; then I would surely have the best of both worlds.[23] (This difficulty is an instance of what is nowadays called "the free-rider problem": although it is in a person's rational self-interest to agree to cooperate, it is also in his rational self-interest to cheat when he can do so secretly—thus taking a "free ride"; but since everybody will figure out that everyone will cheat when given the opportunity, no one will trust the agreement.)
What, in contrast, is Plato's view of justice? According to Plato, justice is something beyond and above the fact that individuals prefer this or have agreed to that: some pleasures, and so, some preferences, are simply bad[24] or false[25] because they encourage one to aim at what merely appears to be good. Since there is an independent and objective reality behind the preferences and agreements of people—since knowledge of the Forms provides an independent and absolute way to determine the truth of moral matters,[26] it would be monstrous to resort to a "market place of ideas," a cafeteria for preferences—as urged by empiricists such as Mill. No rational parents would allow their young child to veto his pediatrician's urgent recommendation for surgery on the grounds that, after extensive discussion in kindergarten, he and most of his peers were convinced that the pain would outweigh the pleasure. Yet, according to Plato's theory, most of us are in the position of that child: we are incapable of gaining and evaluating knowledge, and can only react to superficial considerations—our anticipations of pain and pleasure.[27]
A just person, or a just state, is one whose parts function in proper balance and harmony—there is a natural order here that is independent of human decision. Plato conceives of each part of such an organic whole as having its own proper function, with the various parts so interrelated that it is in the interest of all that each part perform its proper function.[28] Therefore, in a state—that is, in any state, not just a perfect one—there exists a natural identity of interests[29] among all members; this identity of interests exists whether it is recognized or not. Because the interests of the members of a community are not really independent of each other, the rhetorical maxim of the individualist—"it's his life, after all"—is false. So the requirements of justice are not creatures of human decision, but are necessarily true. Thus, the trouble with Thrasymachus is that he does not even begin to understand what a community is all about, and he therefore fails to understand himself. (Of course, an empiricist might retort that the trouble with Plato is that, like other college presidents, he was subject to a state of wistful dreaming—about a community without querulous factions.)
I want you to see, then, how the various political measures endorsed by Plato—state censorship, the state's determining the true interests of its citizens, citizens' being required to practice their special jobs irrespective of their desires, the state's rigid control over the family life and the reproduction of its citizens—all make sense given Plato's theory of rationalism. If you want to examine those measures critically, you will need to come to terms with Plato's more abstract views.
—William S. Boardman
AN AFTERWORD
In the lecture, I have tried to help you understand the machinery behind Plato's views so that you will see the coherence and plausibility of Plato's arguments. But after you have understood the Republic well enough to see and feel its attractions, there are some practical problems which you might consider as well as those concerning his abstract theory.
In Plato's ideal state, it is the actual philosophers who are rulers, and they obligingly convince their citizens of the truth—that the rulers possess knowledge and are thus fit to rule; and because the rulers are genuine philosophers, they really do recognize that their interests are utterly identical with the interests of the entire state and its citizens, and accordingly will not be tempted to gain apparent, self-interested advantage by exploiting their citizens. Yet, according to Plato's theory, the ordinary citizens are not able to know that what the rulers tell them is true, since ordinary citizens lack the native abilities necessary for the rigorous education required to gain knowledge of anything. The ordinary citizens are able to have "true belief"—if they have been convinced to believe something which is in fact true; but they will not be capable of knowing that what they believe is true. Thus, what the rulers convey to their people is propaganda—claims whose appearance is so fashioned that ordinary citizens will happen to find them believable. Indeed, dedicated artists of Plato's state will, following the directions of the rulers concerning the proper messages to be advanced, exert their artistic expertise to fashion didactic "literature" and "art" and "music"—"didactic" because its reason for existence is not its inherent aesthetic value, but its effectiveness in bringing about strong belief in those messages deemed correct by the rulers.[30] For Plato, good literature must be effective in preaching the correct messages.
But what is to prevent a Sophist from falsely making these same claims of esoteric knowledge and fitness to rule which Plato's rulers truly make? And what would prevent such a Sophist from appearing to the ordinary citizen as more trustworthy and knowledgeable than the actual philosopher? (For, remember, the actual philosopher cannot present to the ordinary citizen those things which would actually show that his claims are true, for such things would be, as it were, Greek to the ordinary citizens; they have not the ability to understand such a presentation.)
Consider the problem, then, of someone—call him Citizen Ralph—who is not a potential philosopher-ruler (and given what Plato says, I imagine most of us are in his position); assuming Plato's theory to be correct, how is he supposed to assess the claims of someone, call her "Sophie," who puts herself forward as qualified to be ruler? We can see how someone who is a potential philosopher-ruler would be able to assess Sophie's claims, for he would have the special knowledge which would enable him to know about Sophie's pretensions. But all the rest of the citizenry, not having the wherewithal to gain genuine knowledge of any kind, must fall back on mere opinion. Now Ralph might simply adopt utterly blind trust or faith in Sophie; but what guarantee has he that his trust is well placed? For Ralph has access solely to the appearances of claims—that is, to their seeming to be justified. But is it rational and prudent for a bloke, such as Ralph, simply and blindly to trust a person such as Sophie—who might, for all Ralph knows, be a Sophist in disguise? Wouldn't Ralph be a fool—be utterly irrational—not to resort to the only means he has for drawing any distinctions: the apparent plausibility of the claims, given his experience?
Of course, even opponents of Plato will concede that there is a need in any state or any society for its citizens to trust officials and each other in order that the state or society can function effectively. The practical problem is how one is to determine whether such trust is well placed.
Secondly, suppose we grant that there is something special about mathematical knowledge; as you may recall I earlier referred, in a footnote, to a discussion of Descartes—whose views are astonishingly similar to Plato's—where I have tried to show in what ways mathematical knowledge is special. But, however that special nature of mathematics is to be accounted for—and curiously, one need not be a philosopher-ruler to see that mathematics is special—must we then accord the same status to morality, and grant that some people have the ability to discern, unerringly, absolute truths of morality? Well, suppose for now that we do grant this as well. But then how are we to know which people have actually apprehended these truths? The difficulty is similar to that which we just noted with Citizen Ralph: evidently, only someone who himself has the ability directly to apprehend such truths is able to tell whether somebody else who claims to have done this is merely faking it or has really done it. And if we can't tell, should we simply trust anyone who says he has a direct line to these remarkable truths? One has merely to read the newspapers to discover that many different people claim to possess such abilities; perplexingly, they announce quite different and incompatible "truths," and urge us to censor anyone who speaks otherwise—since it is irrational to allow people to take seriously beliefs which contradict what is known to be true. The problem, though, is that if we don't know these things to be true, it would seem foolish simply to take self-professed experts at their word—or to take the most self-assured one at his word.
These are some of the kinds of worry which trouble Karl Popper, author of The Open Society and Its Enemies, who thinks of Plato's Republic as a sort of source-book for totalitarians. Come to think of it, lots of people have been killed or tortured because they were seen as enemies of an established truth—the late Soviet Union serving as a memorable example, though history is replete with instances of various religious groups exterminating other, "false believing," groups. The danger presented by someone who is convinced that he possesses absolute knowledge is that he isn't very tolerant of others who are—as he sees them—propounding patent falsehoods. So now that you have studied Plato, perhaps you might want to consider carefully the views of John Stuart Mill, whom I mentioned earlier.
See also Notes on Teaching Plato's Republic