Plato on Knowledge and Forms: Selected Essays. Knowledge and True Belief in the Meno. Oxford Studies in Ancient Philosophy, 21, 1, p. Is Justified True Belief Knowledge? Analysis, 23, p. Evanston, Northwestern University Press. Propositions or Objects? Phronesis, 41, 3, p. Protagoras and Meno. New York, Peguin.
Knowledge and the Known. Dordrecht, D. Phronesis, 5, 2, p. Rio de Janeiro, Loyola. The Journal of Philosophy, v. Boulder, Westview. LUZ, A. Pelotas, NEPFil online. Natal, Edufrn. Oxford, Clarendon. Madison, The University of Wisconsin Press. Empirical Justification. The Oxford Handbook of Epistemology. Lisboa, Gulbenkian. Warrant: The Current Debate. Tomo II. Plato Meno.
London, University of Notre Dame Press. Knowledge and Belief. The objects of thought, it is now added, are those objects of perception to which we have chosen to give a measure of stability by imprinting them on the wax tablets in our minds. Aeschylus, Eumenides This new spelling-out of the empiricist account of thought seems to offer new resources for explaining the possibility of false belief. The new explanation can say that false belief occurs when there is a mismatch, not between two objects of thought , nor between two objects of perception , but between one object of each type.
This proposal faces a simple and decisive objection. No one disputes that there are false beliefs that cannot be explained as mismatches of thought and perception: e. Such mistakes are confusions of two objects of thought, and the Wax Tablet model does not dispute the earlier finding that there can be no such confusions. So the Wax Tablet model fails. There is of course plenty more that Plato could have said in criticism of the Wax Tablet model. In the present passage Plato is content to refute the Wax Tablet by the simplest and shortest argument available: so he does not make this point.
But perhaps the point is meant to occur to the reader; for the same absurdity reappears in an even more glaring form in the Aviary passage. If we had a solution to the very basic problem about how the empiricist can get any content at all out of sensation, then the fourth proposal might show how the empiricist could explain false belief involving perception. It attempts this by deploying a distinction between knowledge that someone merely has latent knowledge and knowledge that he is actually using active knowledge.
The suggestion is that false belief occurs when someone wants to use some item of latent knowledge in his active thought, but makes a wrong selection from among the items that he knows latently. If this proposal worked it would cover false arithmetical belief. But the proposal does not work, because it is regressive. If there is a problem about the very possibility of confusing two things, it is no answer to this problem to suppose that for each thing there is a corresponding item of knowledge, and that what happens when two things are confused is really that the two corresponding items of knowledge are confused a—b.
The Aviary rightly tries to explain false belief by complicating our picture of belief. But it complicates in the wrong way and the wrong place. It is no help to complicate the story by throwing in further objects of the same sort as the objects that created the difficulty about false belief in the first place.
At first only two answers seem possible: either he decides to activate 12, or he decides to activate If he decides to activate 12, then we cannot explain the fact that what he actually does is activate 11, except by saying that he mistakes the item of knowledge which is 11 for the item of knowledge which is But this mistake is the very mistake ruled out as impossible right at the beginning of the inquiry into false belief a—c.
Alternatively, if he decides to activate 11, then we have to ask why he decides to do this. At e1 ff. Theaetetus suggests an amendment to the Aviary. This is that we might have items of ignorance in our heads as well as items of knowledge.
As Socrates remarks, these ignorance-birds can be confused with knowledge-birds in just the same way as knowledge-birds can be confused with each other. So the addition does not help. At d—c Socrates argues more directly against D2. He offers a counter-example to the thesis that knowledge is true belief. A skilled lawyer can bring jurymen into a state of true belief without bringing them into a state of knowledge; so knowledge and true belief are different states. This implies that there can be knowledge which is entirely reliant on perception.
One way out of this is to deny that Plato ever thought that knowledge is only of the Forms, as opposed to thinking that knowledge is paradigmatically of the Forms. For this more tolerant Platonist view about perception see e. Philebus 58d—62d, and Timaeus 27d ff.
D3 apparently does nothing at all to solve the main problems that D2 faced. Besides the jurymen counter-example just noted, — showed that we could not define knowledge as true belief unless we had an account of false belief.
This problem has not just evaporated in — It will remain as long as we propose to define knowledge as true belief plus anything. Significantly, this does not seem to bother Plato—as we might expect if Plato is not even trying to offer an acceptable definition of knowledge, but is rather undermining unacceptable definitions.
One crucial question about Theaetetus — is the question whether the argument is concerned with objectual or propositional knowledge.
This is a basic and central division among interpretations of the whole passage —, but it is hard to discuss it properly without getting into the detail of the Dream Theory: see section 8a. Is Plato thinking aloud, trying to clarify his own view about the nature of knowledge, as Revisionists suspect? Or is he using an aporetic argument only to smoke out his opponents, as Unitarians think? The evidence favours the latter reading.
So it appears that, in the Theaetetus , Plato cannot be genuinely puzzled about what knowledge can be. Nor can he genuinely doubt his own former confidence in one version of D3. If he does have a genuine doubt or puzzle of this sort, it is simply incredible that he should say what he does say in — without also expressing it. In particular, he wants to put pressure on the empiricist theories of knowledge that seem to be the main target of the Theaetetus.
What Plato wants to show is, not only that no definition of knowledge except his own, D3, is acceptable, but also that no version of D3 except his own is acceptable.
Rather as Socrates offered to develop D1 in all sorts of surprising directions, so now he offers to develop D3 into a sophisticated theory of knowledge. Taken as a general account of knowledge, the Dream Theory implies that knowledge is only of complexes, and that there can be no knowledge of simples.
Socrates attacks this implication. A common question about the Dream Theory is whether it is concerned with objectual or propositional knowledge. On this reading, the Dream Theory claims that simple, private objects of experience are the elements of the proposition; thus, the Dream Theory is both a theory about the structure of propositions and a theory about simple and complex objects. If the Dream theorist is a Logical Atomist, he will think that there is a clear sense in which people, and everything else, are composed out of sense data.
He will also think that descriptions of objects, too, are complexes constructed in another way out of the immediately available simples of sensation. For such a theorist, epistemology and semantics alike rest upon the foundation provided by the simple objects of acquaintance.
Both thought and meaning consist in the construction of complex objects out of those simple objects. Philosophical analysis, meanwhile, consists in stating how the complexes involved in thought and meaning are constructed out of simples. This statement involves, amongst other things, dividing down to and enumerating the simple parts of such complexes.
What then is the relation of the Dream Theory to the problems posed for empiricism by the discussion of D2 in —? The fundamental problem for empiricism, as we saw, is the problem how to get from sensation to content : the problem of how we could start with bare sense-data, and build up out of them anything that deserved to be called meaning.
Plato thinks that there is a good answer to this, though it is not an empiricist answer. Sense experience becomes contentful when it is understood and arranged according to the structures that the Forms give it. The empiricist cannot offer this answer to the problem of how to get from sensation to content without ceasing to be an empiricist.
What the empiricist can do is propose that content arises out of sets of sense experiences. We get to the level of belief and knowledge only when we start to consider such sets: before that we are at the level only of perception. Our beliefs, couched in expressions that refer to and quantify over such sets, will then become knowledge a when they are true, and b when we understand the full story of their composition out of such sets.
To this end he deploys a dilemma. A complex, say a syllable, is either a no more than its elements its letters , or b something over and above those elements. If I am to know a syllable SO , and that syllable is no more than its elements, then I cannot know the syllable SO without also knowing its elements S and O. Indeed, it seems that coming to know the parts S and O is both necessary and sufficient for coming to know the syllable SO.
This result contradicts the Dream Theory. In that case, to know the syllable is to know something for which knowledge of the elements is not sufficient. But then the syllable does not have the elements as parts: if it did, that would compromise its singularity.
And if the elements are not the parts of the syllable, nothing else can be. So the syllable has no parts, which makes it as simple as an element. Thus if the element is unknowable, the syllable must be unknowable too. This result contradicts the Dream Theory too. Finally, in a1—c2, Plato makes a further, very simple, point against the Dream Theory. Our own experience of learning letters and syllables shows that it is both more basic and more important to know elements than complexes, not vice versa as the Dream Theory implies.
Since such a person can enumerate the elements of the complex, i. Since he can arrange those letters in their correct order a9—10 , he also has true belief. Why not, we might ask? To see the answer we should bring in what Plato says about syllables at d8—a3. Those principles are principles about how letters form syllables, and how syllables form names.
It might even be able to store such a correct ordering in its electronic memory. What is missing is an awareness of bridging or structuring principles, rules explaining how we get from strings of symbols, via syllables, to representations of Greek names. So, presumably, knowledge of say Theaetetus consists in true belief about Theaetetus plus an account of what differentiates Theaetetus from every other human.
Socrates offers two objections to this proposal. The Theaetetus is an extended attack on certain assumptions and intuitions about knowledge that the intelligent man-in-the-street—Theaetetus, for instance—might find initially attractive, and which some philosophers known to Plato—Protagoras and Heracleitus, for instance—had worked up into complex and sophisticated philosophical theories.
The first part of the Theaetetus attacks the idea that knowledge could be simply identified with perception. Perceptions alone have no semantic structure. So if this thesis was true, it would be impossible to state it. The second part attacks the suggestion that knowledge can be defined as true belief, where beliefs are supposed to be semantically-structured concatenations of sensory impressions. Against this Plato argues that, unless something can be said to explain how impressions can be concatenated so as to give them semantic structure, there is no reason to grant that the distinction between true and false applies to such beliefs any more than it does to perceptions.
Finally, in the third part of the Theaetetus , an attempt is made to meet this challenge, and present some explanation of how semantic structures can arise out of mere perceptions or impressions. On this conception, knowledge will come about when someone is capable not only of using such logical constructions in thought, but of understanding how they arise from perception.
Without such an explanation, there is no good reason to treat the complexes that are thus logically constructed as anything other than simples in their own right.
We need to know how it can be that, merely by conjoining perceptions in the right way, we manage to achieve a degree of semantic structure that for instance makes it possible to refer to things in the world , such as Theaetetus.
But this is not explained simply by listing all the simple perceptions that are so conjoined. Nor—and this is where we reach the third proposal of b11—a9—is it explained by fixing on any of those perceptions in particular, and taking it to be the special mark of Theaetetus whereby reference to Theaetetus is fixed.
The third proposal about how to understand logos faces the difficulty that, if it adds anything at all to differentiate knowledge of O from true belief about O , then what it adds is a diagnostic quality of O. If there is a problem about how to identify O , there is a problem about how to identify the diagnostic quality too. This launches a vicious regress.
One way of preventing this regress is to argue that the regress is caused by the attempt to work up a definition of knowledge exclusively out of empiricist materials. Hence there is no way of avoiding such a vicious regress if you are determined to try to define knowledge on an exclusively empiricist basis.
The right response is to abandon that attempt. Knowledge is indeed indefinable in empiricist terms. In those terms, it has no logos. In those terms, therefore, knowledge itself is unknowable. The official conclusion of the Theaetetus is that we still do not know how to define knowledge.
Even on the most sceptical reading, this is not to say that we have not learned anything about what knowledge is like. As Theaetetus says b6 , he has given birth to far more than he had in him. And as many interpreters have seen, there may be much more to the ending than that. Perhaps understanding has emerged from the last discussion, as wisdom did from d—e, as the key ingredient without which no true beliefs alone can even begin to look like they might count as knowledge. Perhaps it is only when we, the readers, understand this point—that epistemological success in the last resort depends on having epistemological virtue—that we begin not only to have true beliefs about what knowledge is, but to understand knowledge.
Duke, W. Hicken, W. Nicholl, D. Robinson, J. Strachan, edd. Plato Plato: method and metaphysics in the Sophist and Statesman Plato: middle period metaphysics and epistemology Platonism: in metaphysics.
The authors and SEP editors would like to thank Branden Kosch for noticing a point of Greek grammar in need of correction. Introduction 2. Summary of the Dialogue 3. Overall Interpretations of the Theaetetus 4. The Introduction to the Dialogue: a—e 5.
Definition by Examples: a—d 6. The Introduction to the Dialogue: a—e We should not miss the three philosophical theses that are explicitly advanced in the Introduction. To learn is to become wiser about the topic you are learning about d8—9.
For instance, the outline shows how important it is for an overall understanding of the Theaetetus to have a view on the following questions of detail more about them later : At a—c, is Socrates just reporting, or also endorsing, a Heracleitean flux theory of perception? What is the date of the Timaeus , which seems 28—29, 45b—46c, 49e to present a very similar theory of perception to that found in Theaetetus —7?
The closer he takes them to be, the more support that seems to give to the Revisionist view that the whole of — is one gigantic modus tollens. The more separate they are, the better for those versions of Unitarianism that suggest that Plato wants to pick and choose among the positions offered in — So much for the overall structure of —; now for the parts. Qualities do not exist except in perceptions of them e3—a8. A distinction between bare sensory awareness, and judgement on the basis of such awareness.
This is where the argument ends, and Socrates leaves to meet his accusers. Conclusion The Theaetetus is an extended attack on certain assumptions and intuitions about knowledge that the intelligent man-in-the-street—Theaetetus, for instance—might find initially attractive, and which some philosophers known to Plato—Protagoras and Heracleitus, for instance—had worked up into complex and sophisticated philosophical theories.
Allen, R. Ast, F. Berkeley, G. Bostock, D. Burnyeat, M. Campbell, L. Chappell, T. Cherniss, H. Cherniss, Selected Papers , Leiden: Brill, , pp.
Cornford, F. Crombie, I. Denyer, N. Cleary and W. Wians eds. Geach, P. Locke, J. Nidditch ed. Lutoslawski, W. McDowell, J. Owen, G. Owen, Logic, Science, and Dialectic , M. Nussbaum ed. Penner, T. Cambridge: Cambridge University Press. Quine, W. Robinson, R. Ross, W. Runciman, W. Russell, B. These line segments are equal - or rather, you believe them to be so.
What is the basis of your belief that they are equal? He deduces correctly that you must first have some information about the size of the segments, which you acquire through evaluating information provided by your senses. The problem, however, is how you know the concept of equality. Were you taught it?
It cannot be, because senses are non-eternal, and prone to error. On the other hand, Equality, as one of the good forms, is eternal and cannot change. Thus, if the concept of Equality is changeless, the only way you can know it is if you have experienced it before in a plane where Equality as a Form is present, truthful, eternal, and changeless. Thus, the soul is immortal and passed through such a plane and retained knowledge, albeit unconscious and hidden, of the Forms.
While Plato believed in reincarnation at the time of the middle period of his writings, it is to be noted that he changed his mind on some of his fundamental beliefs as indicated in his later works. Knowledge is based on real things about which we come up with true propositions in the process of acquiring knowledge. These ideas or objects are universal in that they can be applied to a wide range of real objects to describe or characterize them. Taking this viewpoint, he goes on to say that this world is flawed and full of error, preventing us from really seeing and understanding the true Forms.
Take, for example, the concept of Beauty. Thus, Beauty is both a characteristic and an essence in itself capable of interaction.
That is the concept of self-predication. In this illustration, Beauty Itself is utterly and solely beautiful and exists apart from these other objects that partake of it. In the Phaedo, Plato's theory of knowledge emphasizes this nature of the Forms and calls them monoeides.
Thus, all other objects are of a lesser degree of beauty than Beauty, which Itself is completely beautiful. However, there are differing opinions about whether beauty is a characteristic of Beauty itself, or that the Form and essence of Beauty are the same thing.
In any case, Plato solved the problem of universals, an ancient philosophical question about whether the characteristics of objects, such as color and shape, exist beyond the objects themselves.
Plato would go on to dedicate significant effort to each of these Forms in his later dialogues, believing that the philosopher gains true knowledge by grasping the world of Forms with his mind despite the only evidence of reality being poor and perhaps erroneous copies of the Forms.
These archetypes are the true nature of reality, or at least the little of it that we know. In other words, these images are a representation of the True Forms, though we see them in poor light.
Suppose that there are people in a cave, chained to its wall. They are unable to turn their faces, and all they can see is the wall of the cave. There are shadows dancing on the walls because of a fire that burns behind them, illuminating various objects in passing.
However, because they are unable to turn their faces, all the people can see are mere shadows. This very basic illustration of the cave allegory services to describe the theories that follow. The prisoners - for that is what the people are - have no other reality except what they can see in the shadows on the cave wall.
They can hardly perceive there being any other reality than the one they can see, thus mistaking appearance for reality. Plato then posits a question: when the prisoners are talking about the things they see on the wall, what are they talking about?
For example, were they to see a car in the shadows and said, there is a car. Thus, by extension, the names we attribute to objects in our worlds are not their actual names, but rather just the names of the shadows. Only by being released from our chains can our understanding be freed to see the real Forms behind the shadows. The chained prisoners start a guessing game to predict what image will come next.
If, by chance, one of them predicts correctly, he will be praised by the others as being clever and intelligent. Thus, empirical knowledge of the world around us is praised and desired.
Suppose that one prisoner is freed, so that he is able to turn around and see what is behind him. However, as his eyes adjust to it, he would see and realize that what is on the cave wall are mere shadows of other objects.
However, as you can see, he would first need to climb a steep incline to find the fire and the real objects, or Forms. Just beyond the fire, the prisoner would see the light of the sun filtering into the cave. He would then realize that there is a much greater and better Light, and he might follow it to the outside of the cave where the whole world awaits. However, having been so long in the cave, the bright sunlight would dazzle him, perhaps even blind him temporarily.
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