a companion to plato || plato: a theory of perception or a nod to sensation?

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plato: a theory of perception or a nod to sensation?

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Plato: A Theory of Perception ora Nod to Sensation?

DEBORAH K. W. MODRAK

The challenge when writing about Plato on perception is showing that Plato hadanything to say on this topic that is both interesting and constructive. His frequentdenigrating remarks about perceptible objects, particularly in the middle period dia-logues, have led many scholars to conclude that he allows perception little or noepistemic role in cognition and that its only role is to contribute to delusory opinions.This is not to say that Plato rejects the phenomena of sensation, but rather to say thathe rejects any notion of perception as a full-fledged cognition that might constituteknowledge or be a state upon which knowledge might be based. Is this his position ordo his critical remarks belie an acceptance of perception as a source of true beliefs?

Socratic Dialogues

If we turn to the early Socratic dialogues for answers to these questions, we find verylittle discussion of perception. These dialogues tend not to engage in much criticalreflection about the nature of human cognition. Typically Socrates is energeticallypursuing questions about the nature of virtue; he often defends (or seems to defend)various theses about wisdom, which he identifies with virtue (see 22: THE UNITY OFTHE VIRTUES). He seeks the knowledge that would be constitutive of virtue and showsthat many who claim to have this knowledge lack it. Questions about the reliability(or lack thereof ) of perception simply do not arise. Perception is only occasionallymentioned and when it is, it is not the focus of the discussion. Perception is invokedto illustrate certain points in various arguments about virtue. In the Charmides, whilechallenging the thesis that temperance is a science of science, Socrates secures agree-ment to the claim that if hearing hears itself, it will hear itself possessing sound (168d2–e1). Socrates uses the example of the eye seeing itself in Alcibiades I to provide insightinto how the soul might come to know itself (132d2–133c6). In the Laches, he arguesthat in order to add sight to the eyes to make them better, we must know what sight is(190a1–b1). In the Lysis, he appeals to the difference between hair looking whitebecause it is white with age and its looking white because it has been painted white(217d1–e3). In none of these contexts is perception as such subjected to criticalscrutiny, and its general reliability is taken for granted.

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A Companion to PlatoEdited by Hugh H. Benson

Copyright © 2006 by Blackwell Publishing Ltd

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deborah k. w. modrak

The Meno, a transitional dialogue, raises the question, what is virtue? But much ofthe discussion addresses a different question: is virtue teachable? And the related ques-tion: is virtue knowledge? Perception is not explicitly discussed but assumptions aboutits veracity figure in these arguments. Socrates uses a drawing in the sand to lead aslave-boy away from the boy’s false beliefs about squaring the diagonal to his innatecorrect belief (82b9–85d1). While the slave-boy does not learn the right answer fromthe diagram but recollects it, the prominent role assigned a visual aid in a dialecticaleffort to uncover the truth is striking (see 9: PLATO ON RECOLLECTION). It showshow perception in concert with reasoning may be a tool for recognizing the truth. Thediscussion of recollection is followed by a discussion of the respective roles of true beliefand knowledge in guiding behavior (97a3–99c10). Both are equally sound but theformer, unlike the latter, is unstable. The person who has actually made the trip toLarissa is said to have knowledge, whereas the person who has been told the way has,at best, true belief (97a3–b3). This illustration of the difference between knowledgeand true belief implicitly privileges direct perception over information acquired throughverbal reports (see 11: KNOWLEDGE AND THE FORMS IN PLATO). Despite differencesin context, a later dialogue, the Theaetetus, also privileges direct experience in relationto inferential judgment. The eyewitness to a crime is said to have knowledge whereasthe jurors have, at best, true belief based on the reports of eyewitnesses (201a7–c2).

In the early dialogues, then, Socrates takes the reliability of perception for grantedbut he otherwise pays scant attention to it. Questions about the nature of perceptionor its limitations are not to be found. In the Meno, perception even plays a key butunacknowledged role in grounding the distinction between knowledge and true belief.

Phaedo

More than any other dialogue, the Phaedo advocates the separation of the soul and itspowers from the body. In this context, we would expect to find a very critical assess-ment of perception and we do. Socrates argues for the importance of the intellectseparating itself from the body in order to grasp the truth (65a9–66a8; cf. 99e1–6).To make clear what it is to grasp realities that are inaccessible through the senses,Socrates asks rhetorically, “Do men find any truth in sight or hearing?” He and Simmiasagree that the soul is deceived whenever it examines anything to do with the body.This description of perception seems to leave little room for any of the senses playing aconstructive role in inquiry. Perception appears to be a source of worthless informa-tion at best and to have little share in clarity or precision. It is worth noting, however,that this passage occurs in the context of an argument to show that the philosopherhas been pursuing a goal throughout his life – the separation of soul from body – thatcan only be achieved fully in death.

In a subsequent argument for the existence of ideal objects such as the Equal-itself,Socrates seems to take a somewhat different line on perception. While perception graspsthat two objects are equal, it does so by employing a concept of equality that could nothave arisen on the basis of perceptions of equal things (74d4–75b8). It is striking thatin this context Socrates allows the application of concepts in perception that are notacquired through perception. He assumes that things are seen and heard as equal.

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This assumption is or appears to be in conflict with the earlier claim that the senses arewholly unreliable. As portrayed in the discussion of equality, the perceiver perceivesequal things by applying a concept of absolute equality to them and at the same timerecognizes that perceptible equals fall short of absolute equality (74d3–e4). That atypical percipient would recognize the difference between absolute equality and theequal things that she perceives is essential to the argument that the concept of equal-ity is not acquired through perception. To have the required argumentative force, theclaim must be a general one, i.e., that any self-reflective and reasonably astute perceivercan and will recognize the difference. Although the intellect would be deceived were itto confuse perceptible equals with absolute equality, it seems in no danger of doing so.The possibility of deception remains, but not the certainty of it, as is suggested by theearlier passage. A similar acceptance of perceptually based beliefs figures in the defenseof teleological explanation (96a6–99d2). Pre-Socratic physicalism is rejected on thegrounds that physical causes cannot explain many phenomena satisfactorily. Bothcosmic order and deliberate action can, Socrates argues, only be adequately explainedby an appeal to teleological causes. At no point in this critique does Socrates challengethe veracity of sense-perception or empirically based beliefs.

While arguing for the immortality of the soul on the basis of the difference betweenthe body and the soul, Socrates again emphasizes the differences between physicalobjects and ideal ones (78b4–81a2). The former are constantly undergoing change;the latter are unchanging. The former are grasped through the senses; the latter, bythe mind alone. The changeable nature of physical objects is such that the intellectbecomes confused when it makes use of the body. Because the objects that are per-ceptible are unstable, philosophy persuades the soul to withdraw from the senses (83a1–c3). The goal of philosophy is to grasp unshakeable truths.

Even while voicing reservations about perceptible objects and perceptual powers,the Phaedo allows perception to play a significant role in cognition. Perception pro-vides reliable information about the physical world. A human perceiver is even able toapply general concepts such as equality in perception. The limitations of perceptionare a reflection of the limitations of concrete objects in comparison with ideal objects.

Republic

At first blush with respect to cognition, the Republic may seem to proceed in much thesame way as the Phaedo. It does not appear to be a very likely place to find supportfor the thesis that perception grasps the truth about perceptibles. Many well-knownpassages contrast unreliable opinings to steadfast knowledge. The objects of opinionare accessible through perception; the objects of knowledge are accessible only throughthought unaided by the senses. Lovers of sights and sounds are found to be wantingin comparison to lovers of truth (474d3–480a13). In a famous illustration, Socratesdivides a line drawn on the sand to display the relative rankings of cognitive powersand their objects (509d1–511e3). The main division of the line is between thevisible realm and the intelligible realm. The activity of dialectic that makes no use ofperceptibles but proceeds through intelligibles alone is praised as the highest cognitivepower (511b3–c1; 533a8–534d1).

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Yet, on a closer reading of these and related passages, we find a subtle distinctionbetween the grasp of genuine perceptibles and the apprehension of more generalfeatures.

I’ll point out, then, if you can grasp it, that some sense perceptions don’t summon theunderstanding to look into them, because the judgement of sense experience is itselfadequate, while others encourage it in every way to look into them, because sense percep-tion seems to produce no sound result. (523a10–b4, trans. Grube)

When we perceive the same finger as large in one context and small in another, theintellect is prodded by the puzzle to think about the nature of the great and the small(523b10–525a2). This case is contrasted with the simple perception of a finger. Sightis capable of providing fully adequate information about the color and shape of itsobjects and of applying certain unproblematic concepts such as that of being a finger.Certain general features, however, for instance, being beautiful or being large are suchthat they are grasped in perception in a way that is ambiguous. It is always possible toperceive the same object as having general features that are opposed to the initiallyperceived features. For instance, a sound that is beautiful in one context may be dis-cordant and ugly in another. A finger that is large in relation to one finger may besmall in relation to another. As a consequence, any attempt to make general claims onthe basis of perceptions alone about such features is problematic.

This explains the difference in tone between the passage at 523a10–b4 and thedescription of the lovers of sights and sounds as living in a dream state at 474d3–480a13. Here, too, the role of perception is implicitly a prompt to further philosophiz-ing; philosophers are said to be like the lovers of sights and sounds (475e2), in thatboth groups are lovers of beauty. Unfortunately, however, the lovers of sights andsounds do not recognize that the physical manifestations of beauty that they love arebut likenesses of beauty. They confuse the likeness with the thing itself. Plato does notdescribe their cognitive condition in terms of having false perceptions but rather as acase of false opinion. What makes the opinion problematic is the generalization fromthe core perception to a further identity claim about the object, i.e., that it is Beauty-itself. The lover of sights and sounds makes an error that the hypothetical perceiver ofequality in the Phaedo avoids. Because the object of opinion is a conflation of a likenesswith a reality, it is said to be halfway between what is and what is not (478d3).

The picture of human cognitive powers illustrated by the divided line is also inevidence in the discussion of the education of the guardians in Republic VII (see 16:PLATO AND MATHEMATICS). Socrates distinguishes between astronomy as it ispracticed by his contemporaries and true astronomy (528d5–530c1). The former seeksto explain the movements of the celestial bodies precisely as they appear to theobserver. This means that the model will include irregular movements with imperfectorbits. The latter explains observable motions on an idealized geometrical model interms of perfect spheres and regular motions. A similar distinction is drawn in the caseof harmonics; the true harmonics offers a mathematical model of audible sounds. Tothe extent that it is possible to understand observables, a mental shift away from thevisible and audible to the purely intelligible is required. The use of vision to graspobservable motions or of hearing to grasp audible musical notes is not challenged here

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but rather Plato stresses the importance of moving beyond observables. Genuineunderstanding can only be achieved by the study of problems, i.e., by the mentalconstruction of models that are purely mathematical.

Perceptual powers used in relation to appropriate objects are treated with respectin the Republic. The model for intellection is vision under good conditions. Plato drawsan analogy between the sun as the source of light and the Form of the Good (508a4–509a4). Light makes the potentially visible actually visible; the Form of the Goodmakes potentially intelligible objects fully intelligible. Even perceptions that produceconfusion, such as those of largeness and beauty, have an important role to play incognition as prods to further reflection (see 7: PLATO’S METHOD OF DIALECTIC).Philosophical investigation begins with perceptions of qualities such as beauty andlargeness. In the Symposium, although “Diotima’s speech” about love quoted by Socratesdoes not mention perception as such, the same progression from perceptibles tointelligibles is envisaged. The true lover of beauty begins with the beauty of a singlemale body, moves on to all beautiful bodies, then on to beauty as manifested in lawsand customs, and finally arrives at Beauty-itself (210a4–211d1).

In the Republic, perception is the starting point for a cognitive process that, whensuccessful, terminates in the apprehension of ideal objects. The divided line provides avivid picture of the difference between perception and its objects and intellection andits objects. Nevertheless, human cognizers begin in the world of physical objects aspresented in and conceptualized through perception and, on the basis of questionsprompted by perceptions, the inquiring mind moves beyond observable objects.

Timaeus

The creation myth that frames the discussion of the Timaeus spawns a detaileddescription of perceptual mechanisms, especially those of vision (see 14: THE ROLEOF COSMOLOGY IN PLATO’S PHILOSOPHY).

When light surrounds the visual ray, then like falls upon like and they coalesce, and onebody is formed by affinity in the line of vision, wherever the light that falls from withinpresses firmly against an external object it has encountered. And the whole visual ray,being similarly affected, in virtue of similarity transmits the motions of what it touches orwhat touches it over the whole body, until they reach the soul, causing that perceptionwhich we call seeing. (45c2–d2)

The attention to detail is striking in this account. It also makes clear that for Platoperception is a psycho-physical activity that begins with a series of purely physicalchanges – in the medium between the organ and the object and in the perceptualorgan. Hearing and smell, like sight, are caused by changes in a medium; only theorgan of sight interacts with the medium to create the conditions required in order forseeing to take place. Sight, the sense that seems the least amenable to explanationin terms of bodily contact, is described in terms that seem to make it a case of contact.A body is formed that extends through the medium to the organ and causes changesin it. The terminology makes it clear that we are to understand the perceptual process

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solely in terms of physical causality up to the point where the changes in the percipient’sbody cause changes in the soul. A process that begins in physical changes outside thebody of the percipient and ends in changes in the percipient’s mind is constitutive ofperception. All components of the process are necessary for perception to take place.

According to Timaeus, the eyes were the first organs to be fashioned by the gods(45b2–4). Sight is of supreme benefit to human beings; without it “none of our presentstatements about the universe could have been made” (47a1–4). The investigation ofthe universe led thinkers to philosophy (47a4–b2). Despite the importance of vision,Plato continues to circumscribe the range of objects that are accessible through per-ception. The familiar distinction between understanding and true opinion is invokedin order to establish that Forms by themselves are not objects of perception (51d2–52d1). Were true opinion identical to understanding, it is argued, then the objectsperceived through our senses would be the most stable things that are. Since there is adistinction, Forms are more stable than perceptibles.

When Timaeus turns to the properties of the elemental bodies, he says that it will benecessary to appeal to sense-perception at every step in the discussion (61c3–d1). Fireis hot because its shape is such that it cuts bodies into small pieces; moisture is coldbecause it compresses our bodies (61d5–62b6). Whatever our flesh gives way to is hard;whatever gives way to our flesh is soft (62b6–c2). Other perceptible characteristics areexplained in terms of more basic qualities. Roughness is due to a combination of hard-ness and non-uniformity; smoothness is due to a combination of uniformity and density(63e8–64a1). Since these characteristics are a consequence of the shapes of the ele-mental bodies, the perceptible properties mentioned have an objective basis in the thingscausing them. A similar account is given of tastes, odors, sounds, and color (65c1–68b2).

“Color is a flame which flows forth from bodies of all sorts, with its parts proportionalto our sight so as to produce perception” (67c4–d1). Timaeus goes on to explain thatdifferences in color are due to differences in size between the flame emanating fromexternal bodies and the flame emanating from the eye. If there is no difference betweenthe two, the result is transparency. White dilates the ray of sight, and black contractsit. Similar accounts are given of brightness and the other colors, many of which are dueto the mixture of more basic colors. Green, for instance, is a mixture of amber and black.

The description of perceptible qualities, like the earlier description of the visual ray,underscores the importance of the physical mechanisms involved in perception. Thecharacter of a simple perception of a proper object is fully determined by the physicalinteraction between the body of the percipient and external bodies. The content of theperception is explicated in terms of the fit or lack of fit between the relevant physicalcharacteristics of an external body and the organ.

When Timaeus turns his attention to situating the soul in the body, he places theimmortal soul, the seat of rationality, in the head, and the mortal soul in the chest andtrunk. Sense-perception, pleasure and pain, emotion, and appetite are mentioned inconnection with the mortal soul initially, but then sense-perception drops out of theaccount (69d4–6). The descriptions already given of four of the five senses (sight,hearing, smell, and taste) appear to place them in the head. Perception, even onTimaeus’ account, challenges a strict division between mortal and immortal soul. Whilea story might be told about a central sensorium in the chest to which all the individualsense organs attach, this story is not told by Plato. We are left with a puzzling omission

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of a faculty that seems to challenge the physical compartmentalization of differenttypes of soul, despite its having been much discussed prior to the compartmentalization.

Theaetetus

The topic under discussion is knowledge and Theatetus makes various attempts todefine knowledge by identifying it with other cognitive faculties, namely, perceptionand opinion. These are variously characterized. Three different accounts of what itmight mean to say that knowledge is perception are explored. In the end, all are foundunsatisfactory, and the thesis that knowledge is perception is laid to rest at 186e. Thefocus then shifts to various attempts to define knowledge in terms of opinion. For ourpurposes, the Theaetetus is a very important work, because it is the one dialogue inwhich perception is discussed at length in its own right as a cognitive power.

The thesis that knowledge is perception is given three different interpretations and,on each interpretation, the thesis is refuted. On the first interpretation, the thesis issaid to be equivalent to the Protagorean claim that man is the measure of all things.On the second interpretation, it is explicated in terms of a Heraclitean world whereeverything and everyone are in a constant state of flux. Neither the Protagoreanversion of the thesis nor the Heraclitean version holds up under scrutiny. Yet Platorevisits the claim that knowledge is perception. The third refutation, found at 184b4–186e7, is aimed at an unadorned version of the thesis as interpreted by Socrates andTheaetetus. Socrates begins the refutation by distinguishing between objects that areperceived through one faculty and those that are common.

Socrates: Now will you also agree that with respect to the objects you perceive throughone faculty it is impossible to perceive them through another – for instance, to perceiveobjects of hearing through sight or objects of sight through hearing?

Theaetetus: Of course.Socrates: So, if there’s something which you think about both of them, it cannot be some-

thing which you are perceiving about both, either by means of one of the instru-ments or by means of the other. (184e8–185a6)

Theaetetus and Socrates agree that since there is no organ through which the com-mon features (sameness, difference, and being) are perceived, these objects are appre-hended directly by the mind. Since knowledge involves the apprehension of commonfeatures, it cannot be perception. This whole argument, however, depends upon theclaim made above that restricts each sense, and hence perception in general, to objectsthat are not accessible through more than one sense. The challenge for us is to uncoverthe reasons that explain why Theaetetus readily assents to this restriction on percep-tion. More important, does the dialogue offer any justification for this position?

The answer (and the justification of the crucial premise) is found not in the finalargument at 184b4–186e7 but earlier in the dialogue (Modrak 1981). At 156a1–157c2, Socrates puts forward a theory of perception in the context of the Heracliteanflux doctrine. Whether Plato accepts this theory, the so-called “secret doctrine,” hasbeen a matter of controversy. It is noteworthy, however, that critical support for the

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thesis that each sense is limited to its own proper object is found there. According tothis theory, the object of perception is dependent upon the act of perceiving and thestructure of the external object.

When an eye and something else commensurate with it come within range, they givebirth to whiteness together with its cognate perception, which would not have occurred,had either one of these not encountered the other. . . . Then the eye becomes filled withsight and now sees and becomes not sight but a seeing eye; while the other parent of thecolor is filled with whiteness and becomes not whiteness, but a white thing, be it stick orstone or whatever else may happen to be so colored. (156d3–e7)

The object of perception is a phenomenal object; it is created through the interactionof the sense organ and the external object. A later passage reaffirms the identificationof a sense with a capacity of a specific bodily organ (185c3–e1). Taking both pas-sages together, we have the justification needed for the claim that no sense can graspanother’s object. The interaction that takes place between a specific organ, e.g., aneye, and an external object, e.g., a stone, were it to occur in a different organ throughdifferent means, would be a different interaction. Crucially, the product of the inter-action would be a different phenomenal object, e.g., a hard thing. The characteristicsof a sense object reflect its “parentage.”

As developed in the Heraclitean framework of the second part of the Theaetetus(151d7–183a7), this account of perception has the consequence that phenomenalobjects are totally unstable, because both the organ and the external object are con-stantly changing in a Heraclitean universe. As a result, the white thing is whollyephemeral. The same theory of perception, however, in a non-Heraclitean universewhere both organ and external object were fairly stable would yield phenomenalobjects that were also fairly stable.

Perception is identified with the mind’s apprehending sensible features through bodilyfaculties at 184b8–186e10. Included in perception is not only the passive reception ofsensibles but so also is the active investigation of sensible features by the mind. Whenasked through what the mind would think about the saltiness of color and sound,Theaetetus responds that were it possible for the mind to decide the question whethera color or a sound were salty it would do so through the faculty of the tongue. Simplejudgments of the form, X is S, where S is some sensible characteristic, e.g., saltiness,are made through perception. But then what is the difference between judgments ofthis form and knowledge? The difference, according to Socrates, is that knowledgerequires the apprehension of certain common features, namely truth and ousia (being).These features the mind grasps after a long and arduous effort of reasoning aboutthem and thinking about them in relationship to each other over time (186b6–d5). Tograsp the ousia of X is to grasp X embedded in the larger causal and ontological contextthat provides a fully adequate understanding of X. The simple perceptual judgment,“this is salty,” is not knowledge, because it does not address the character of the saltyitem. For knowledge, a non-perceptual recognition that the perceptual judgment isabout a phenomenal feature would be required. Unlike the perception of a sensiblefeature, knowledge would not allow its possessor to confuse the phenomenal objectwith an object having intrinsic stability, a Form.

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The Theaetetus account of perception is quite compatible with the description of thecausal processes involved in perception in the Timaeus. It also explains Timaeus’ reserva-tions about theories about physical objects. The object-as-perceived is accessible throughperception but the object-as-perceived is a product of the interaction between the senseand the external object. We do not have direct access to physical objects. In the Timaeus,the sensible features of objects are analyzed in terms of their underlying geometricalstructures. But Timaeus is cautious in presenting his findings and reminds his audi-ence that the account is only probable. The Theaetetus gives us an account of percep-tion that allows the perceiver to grasp phenomenal objects in a way that providesreliable information about the world as perceived but that, nonetheless, falls short ofknowledge.

Sophist

Perception as such is barely mentioned in the Sophist. In the battle between the Friendsof Forms and the Giants, the antagonists stake out positions that include diametricallyopposed attitudes toward the visible and tangible (246a7–249d4). The Friends of Formsrelegate perceptions to the domain of coming to be in contrast to that of being. TheGiants insist that nothing is except that which possesses tangibility. The Strangerargues that neither position is defensible and that, besides being, the philosopher mustembrace both the unchanging and that which changes (251d5–254d5). Since thechanging nature of physical objects and perceptibles has been the primary reason forrejecting the evidence of the senses in other contexts, making change ontologicallyrespectable would seem to allow perception to be epistemically respectable.

Throughout the discussion of sophistry, the notions of likeness and likeness-makingfigure importantly. A further distinction is drawn between a likeness (eikon) that main-tains true proportions and another kind of likeness, an appearance (phantasma), thatdoes not, and between likeness-making and appearance-making (235c8–236c7,266d2–e4). The elements, animals, and other natural bodies are created by divine artand are likenesses. Sophistry produces appearances in words. The difference betweendivine and human art and the existence of copies that maintain the true proportions oftheir originals would provide a basis for granting the physical world as grasped inperception epistemic legitimacy. This possibility is not explored in the dialogue but is,nonetheless, significant. The causal account of perception in the Timaeus makes thecharacter of the perception a consequence of the elemental shapes causing it. Thisaccount could be developed in light of the Sophist in a way that made the contents ofperceptions likenesses rather than mere appearances. Under these conditions, percep-tions would provide accurate information about stable objects, the characteristics ofwhich would mirror realities (Forms).

Philebus

Pleasure, not perception, is the topic under consideration in the Philebus, but quitea bit is said about perception in the course of the discussion (see 21: PLATO ON

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PLEASURE AS THE HUMAN GOOD). Pleasures and pains have cognitive content;perception is the source of this content. Socrates describes a kind of pleasure thatbelongs to the soul itself. This type of pleasure is dependent upon memory, which inturn is defined in terms of perception. Perception is the motion that occurs when thesoul and body are affected together (34a3–5). Memory is the preservation of percep-tion. On particular occasions, memory and perception write words (logous) in our soul(39a1–7). In addition, perceptual experiences also often give rise to pictures corre-sponding to the verbal inscriptions. Socrates explains how this occurs: “A person takeshis judgments and assertions directly from sight or any other sense and then views theimages in himself of those judgments and assertions” (39b9–c2; trans. Frede). Theinscriptions and the associated pictures are true if they give a correct account, or falseif they do not. This is a complex and provocative account of human cognitive life. Itenvisages the transformation of perceptual information into verbal form as well as theretention of sensible features. The latter mirror the characteristics of the original per-ception. A simpler picture would envisage neither an internal writer nor an internalpainter. The function of both writer and painter is the transfer of incoming perceptualinformation into other media for its preservation in the soul. Perceptions spontan-eously issue in judgments and internal images. This maximizes the amount and kindsof information that the perceiver has access to for current and future use. It is note-worthy that this process, when all goes well, allows perception to be a source ofcompletely reliable information.

In the Philebus, perception is defined in a way that covers the awareness of internalstates as well as perception through the senses. Not only does the soul have awarenessof its own pleasures and pains but it is also aware of the pleasures and pains of thebody. As a consequence, a person sometimes experiences a psychic pleasure thatopposes a bodily pain and a psychic pain that opposes a bodily pleasure (41d1–3). Justas the relative distance of objects from the eyes distorts our perception of their actualsize, so too does the relative temporal proximity of pleasures and pains distort ourperception of them (41e2–42c2; cf. Prt. 356a3–357b2). In both cases, it is possiblefor a discerning perceiver to distinguish between appearance and reality. What dis-tinguishes a false pleasure from a true one is an accurate perception of its content.Socrates appeals to this picture in order to argue against Protarchus’ restrictionof truth and falsity to belief (doxa). False pleasures are said to be ridiculous imitationsof true ones (40c4–6). Here the familiar Platonic distinction between appearance andreality that sometimes seems to separate perception from intellection is being appliedto perceptions of pleasures and pains as well as to judgments. Some perceptions arecorrect and give us information about realities; some are not and present us only withmisleading appearances.

Seventh Letter and Definitions

The authorship of the Seventh Letter is disputed, and the Definitions are undoubtedlya Platonic handbook not written by Plato (see 1: THE LIFE OF PLATO OF ATHENS).Yet since in both works perception is discussed, a brief look at these passages seemsappropriate. The author of the Seventh Letter defends the importance of an oral tradition

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in which the preferred method of philosophy is that of dialectical discussion. It is “onlywhen names, definitions, visual and other perceptions are rubbed together” and testedin discussion that the nature of anything can be understood (344b1–c1). In the Defini-tions, sight is defined as a state of being able to discern bodies (411c9); and perception,as a movement of the soul by the body (414c5–7). In both works, we find the assump-tion that perceptions are often veridical.

Overview

Our survey of the dialogues has revealed certain consistent themes in Plato’s handlingof perception, both in the few explicit discussions of it and in the assumptions, implicitas well as explicit, made about perception. One constant feature is the identificationof perception with a psycho-physical activity in which changes in the body are com-municated to the soul. This activity is the result of the external world’s impacting thebody in various ways. In some cases, for instance, hearing, the body is fairly passivewhile being acted upon by the world; in others, the body contributes to the conditionsthat enable perception to occur, for instance, the visual ray sent out by the eye. Typ-ically, the causal sequence begins in the external world when an object or event actson the sense organ and the movement in the organ is then communicated to the soul.A similar sequence of events takes place internally in the case of the awareness ofbodily sensations, for instance, the awareness of a toothache or an aching back.

Another common feature is Plato’s conception of a cognitive faculty. All cognitivefaculties, perceptual and intellectual alike, are distinguished by their objects (see 19:THE PLATONIC SOUL). Sight is distinct from hearing, because color is distinct fromsound. The objects that we perceive lack the inherent stability that characterizesobjects of thought. Since the object-as-perceived is a consequence of an interactionbetween the perceiver and the external object, the object-as-perceived shares manycharacteristics of the external object causing the perception. The object-as-perceivedis as stable or as unstable as its cause.

In the Republic and other middle period dialogues, the direct apprehension of anobject, such as is found in vision, is the model for intellectual apprehension at its best.Moreover, according to Plato, in the acquisition of information about the world, it isalways epistemically better to have been a percipient than to have been merely arecipient of information from others about the same events or objects. Perceiving theworld directly through the senses is a prerequisite for being in the best epistemic posi-tion one can be in with respect to physical objects.

Other features of perception, however, seem to change from one dialogue toanother. This is especially true of the value attached to cognitive graspings of physicalobjects through perception and the related issue of whether the information that ispresented through perception can serve as the basis for true beliefs. The Phaedo’s claimthat the soul is always deceived when relying upon the body contrasts with the Philebus’acceptance of perception as a source of true opinion.

There are several strategies for resolving these tensions (see 2: INTEPRETING PLATO).On one plausible story line, Plato’s views about perception evolve. They evolve from afairly uncritical acceptance of sense-perception in the Socratic dialogues to considerable

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disenchantment with its capacity to yield anything of any epistemic value in the earlymiddle period to a more nuanced acceptance of its critical capacity in the late dia-logues. There is also an alternative story available that does not assume any particularorder of the dialogues while still attributing a coherent story to Plato. Plato emphas-izes different aspects of a nuanced account of perception throughout. He is alwayswilling to concede a role for perception as a reliable source of information about thephysical world. One reason why perceptions cannot be relied upon to grasp unshake-able truths firmly is that the objects presented in perception are always somewhatunstable. This flaw is rooted in the nature of bodies and the physical world. Plato’sapparent skepticism about the senses is driven by his skepticism about physicalobjects. It is not that the character of the senses is such that we cannot know physicalobjects through the senses but rather that the character of physical objects is such thatwe cannot fully know them. Thus, in order to grasp objects that are fully intelligible,the intellect must separate itself from the presentation of physical objects throughperception. When Plato’s attention shifts to the requirements of knowledge, heemphasizes the importance of apprehensions that are integrated into a whole networkof consistent, true beliefs. From this vantage point, knowledge of perceptibles is possible,although perceptions would still not be instances of knowledge. On either one of thesestory lines, true opinion and even justified true opinion in our sense, but not Plato’ssense, can be based upon perception and often is.

A closely related issue is that of the difference between perception and knowledge.Perceptions sometimes provide misleading information; knowledge never does, butwhat distinguishes the true perception from an instance of knowledge? In many pas-sages, knowledge is described in terms of the immediate grasp of an object. Thusdescribed, knowledge seems very like an instance of perception of a special sort of object.The lover of Beauty-itself seems to stand in the same cognitive relation to Beauty-itself,as does the lover of beautiful sights, when he gazes upon a beautiful body. The differ-ence as developed by Socrates in Republic V (474d3–480a13) is purely in terms of thefeatures of Beauty-itself, its unchanging nature, its being essentially beautiful in everyrespect. Yet, as Socrates goes on to make clear in the discussion of the divided line, theobjects of knowledge, the Forms, are interrelated. We have knowledge when we graspa whole conceptual network and possess a number of interconnected, true propositions.This conception of knowledge and understanding is quite evident in later works suchas the Theaetetus and Sophist. If knowledge is not simply the immediate, perception-likegrasp of independent objects of the right type, namely Forms, then perception, eventhough it has immediacy, provides at best an accurate snapshot. It is always going tofall short of knowledge. Knowledge requires a contextualized understanding basedon grasping all the relevant concepts. The evaluation of the truth of a perceptualjudgment requires the mind to embed the perceptual judgment in a network of beliefs,some of which will employ concepts that are beyond the grasp of perception.

We set out to investigate Plato’s views about the nature of perception. We wonderedwhether Plato allowed perception a role in the acquisition of true beliefs. It is nowclear that an affirmative answer to that question is in order. Plato allows perceptionsto constitute true beliefs, but he does not allow perception by itself to issue directly injudgments about the truth of these beliefs. This is a nuanced position that does notfit particularly well with the standard modern use of “true.” Perhaps the best way to

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express Plato’s position in familiar terms is to say that perceptions may constituteveridical beliefs that are true in the sense that they get it right about the perceivedobject, but true perceptual beliefs do not meet Plato’s criteria for justification. A jus-tified true belief, according to Plato, requires a full understanding of the phenomenonin question. This is the force of the statement in the Theaetetus that perception cannotmake judgments about truth (186b–d). This may also explain those occasionalstatements scattered throughout the Platonic corpus that seem to express sweepingskepticism about the reliability of perception. As we have seen, even in dialogues wheresuch statements are found, other descriptions of perception belie a sweeping condem-nation of perception and suggest that perception is reliable with respect to certainkinds of objects. Despite our initial worries, as it turns out, Plato does have an interest-ing and coherent account of perception as a full-fledged cognitive power.

Note

All translations are the author’s unless otherwise noted.

References and further reading

Bedu-Addo, J. (1991). Sense-experience and the argument for recollection in Plato’s Phaedo.Phronesis 36, pp. 27–60.

Bondeson, W. (1969). Perception, true opinion and knowledge in Plato’s Theaetetus. Phronesis14, pp. 111–22.

Burnyeat, M. (1976). Plato on the grammar of perceiving. Classical Quarterly 70, pp. 29–51.Cooper, J. (1970). Plato on sense-perception and knowledge: Theaetetus 184–186. Phronesis 15,

pp. 123–46.Fine, G. (1990). Knowledge and belief in Republic V–VII. In S. Everson (ed.) Companions to

Ancient Thought, vol. I: Epistemology (pp. 85–115). Cambridge: Cambridge University Press.Frede, M. (1987). Observations on perception in Plato’s later dialogues. In Essays in Ancient

Philosophy (pp. 3–8). Minneapolis: University of Minneapolis.Holland, A. (1973). An argument in Plato’s Theaetetus: 184–186. Philosophical Quarterly 23,

pp. 97–116.Kanayama, Y. (1987). Perceiving, considering, and attaining being (Theaetetus 184–186).

Oxford Studies in Ancient Philosophy 5, pp. 29–82.Modrak, D. K. (1981). Perception and judgment in the Theaetetus. Phronesis 26, pp. 35–54.Nakhnikian, G. (1955). Plato’s theory of sensation. Review of Metaphysics 9, pp. 129–48,

306–27.Schipper, E. (1961). Perceptual judgments and particulars in Plato’s later philosophy. Phronesis

6, pp. 102–9.Turnbull, R. (1978). The role of the “Special Sensibles” in the perception theories of Plato and

Aristotle. In P. Machamer and R. Turnbull (eds.) Studies in Perception (pp. 3–26). Columbus:Ohio State University Press.

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a companion to plato || plato: a theory of perception or a nod to sensation?

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