The Argument from Illusion in Gorgias’ Treatise On What Is Not

Abstract:

The argument from illusion which is also known as the argument from perceptual relativity or from conflicting appearances and sense-impressions, has occurred in many thinkers from antiquity to the present. The conclusions drawn from that argument are different from philosopher to philosopher. In Plato's Republic, the case of the crooked object when in water and similar cases show that there is a weakness in our nature within us revealed by the fact that our sight is liable to illusion and confusion. Aristotle's Protagoreans concluded that one's beliefs about whatever appears, let us say, cold or not cold is true and proceeded to a denial of the principle of contradiction. In Sextus Empiricus, it justifies a scepticism about belief and knowledge in general. In Descartes, it justifies a scepticism about the senses. In Ayer, the argument from illusion proves the existence of sense-data. My intention herewith is to show how Gorgias uses the argument from illusion treating it as related to the problems of the philosophy of perception. No attention has been paid to this issue in the literature.

Keywords:
Gorgias; nonbeing; illusion; Lazerowitz; perception

Introduction

It is useful to schematise Gorgias' reasoning as follows: 1) "It is not (or nothing exists)", 2) "Even if it is, we cannot know it", 3) "Even if we could know it, we cannot convey and tell it to anyone else" (“ouden estin […] ei kai estin, akatalepton anthropo, […] ei kai katalepton, alla toi ge aneksoiston kai anermeneuton to pelas.”, DK B3 65). There are two extant paraphrases of Gorgias' treatise On What is Not, the Sextus Empiricus’ Adversus Mathematicos VII (DK 65-82, 65ff) and the pseudo-Aristotelian text of Bekker (1960), De Melisso, Xenophane, Gorgia 979a5-980b21 (hereafter MXG). For Kerferd (1981, p. 321) both texts are needed for a complete understanding of Gorgias' views. It is also necessary to make a comparative use of both Gorgias' On What is Not and Gorgias' rhetorical works, the Helen and the Defense of Palamedes. Scholars tend to study Gorgias' philosophical and rhetorical works separately; this leads to an incomplete understanding of Gorgias' texts. The Gorgianic philosophical and rhetorical works are interdependent and, if studied together, cast light on each other. For the Helen and the Palamedes, I use the translation of Kalligas (1981) and MacDowell (1982); the translation of the On What is Not is based on Bury (1935) and Hett (1936). For Aristotle’s and Plato’s texts I use Bekker (1960) and Platonis Opera (1995).

One of the first philosophers who treated Gorgias from a philosophical point of view was the Wittgesteinian Lazerowitz according to whom these statements seem to be "the outcome of the empiricist tradition in philosophy" (1968, p. 37). For Lazerowitz, the second statement "even if it is, we cannot know it" is intended by Gorgias to mean that "it is impossible to know the nature or existence of material things", if one's sense-experience is a necessary condition for grasping their nature and existence (Lazerowitz, 1968, p. 38). In the same sense, the third statement "Even if we could know it, we cannot convey and tell it to anyone else" (by means of “logos”) is intended to mean that "a person cannot know that others understand his words as he understands them, or that language is private to its user" (Lazerowitz, 1968, p. 38). This interpretation does not make it clear a) why, for Gorgias, sense-experience is not enough for grasping and knowing the existence and nature of material things, and b) which sort of language is considered by him as a kind of private language. This line of interpretation draws its conclusions from a mere schematization of Gorgias' argument without taking into account the way in which Gorgias argues for those putative views. Nonetheless, it gives Gorgias' reasoning a pure philosophical character, and, as we shall see, it can be substantiated by the texts (Bakaoukas, 2002; 2014).

So, according to this interpretative line, Gorgias' thought is reconstructed as follows: the second statement, "it is impossible to know the nature or existence of material things" is meant to imply that I cannot be sure that my perception of a physical thing is veridical or not, for when I try to check if my perception of a thing is actually a perception of an independently existing physical object, I find myself in an embarrassing situation; the physical thing itself is indistinguishable from our perception of it, so that I cannot compare my perceptions of a thing with the independent thing itself, because such a comparison always ends in a comparison between two perceptions of the thing. Therefore, I can neither know what the properties of the things are nor that there is an independently existent thing (Lazerowitz, 1968, p. 38).

Following this line of reasoning, Gorgias seems to be interested in the problem of perception. That is to say, he deals with the question of how it is possible, as it were, to be sure that the objects we perceive do actually exist independently of our perceiving them, or, as Ayer puts it in The Problem of Knowledge, how is it possible to justify "our belief in the existence of the physical objects which it is commonly taken for granted that we perceive"? (1980, p. 84). It has been argued by contemporary philosophers that what guarantees the existence of physical objects is the fact that they are accessible to more than one sense and to more than one percipient. That is to say, they have the feature of publicity according to which, in Ayer's words, "if anything perceptible is properly to be called a physical object, it must at least make sense to say of it, that it is perceived by different people and that it is, for example, touched as well as seen" (1980, p. 85). Gorgias, in his turn, questions the publicity of things presented to our senses called by him aistheta. He argues that sensible things (“aistheta”) should be distinguished from public physical things (Bakaoukas, 2012b).

Gorgias on private and subjective sense-experiences

Gorgias seems to call into question the publicity of sensible things (“aistheta”) first by appealing to the possibility of there being things that are accessible and private to a single sense and not to more than one sense.¹ For example, he says that visible things (“horata”, DK B3 81) are accessible only to sight in the same way as audible things (“akousta”, DK B3 81) are accessible only to hearing, and furthermore that every sensible thing is private to the sense by which it is perceived. As a result, a color can only be seen and a sound can only be heard.² Gorgias also emphasizes the common sense fact that it is not necessary for many observers to see exactly the same thing at the same time (MXG 980b 9-19). As Gorgias puts it:

For it is possible for the same thing to exist in several separate persons; for then the one would be two. But if the same things were in several persons, there is nothing to prevent it from not being the same in them all, seeing that they are not in every way alike, nor in the same place; for if anything were this, it would be one and not two [sc. persons]. But even the man himself does not seem to perceive similar things at the same time, but different things with his hearing and with his vision, and different again at the moment and long ago, so that one man can hardly perceive the same things as another […] and because no one thinks the same things as another (transl. Hett, 1936)³

In this case, Gorgias says that there is nothing to prevent a thing from seeming different to many persons (“ouden kolyei me homoion phainesthai autois”), since these persons are supposed to be neither exactly the same nor probably in the same vantage ground (“me pante homoiois ekeinois ousin kai en to auto topo”). He simply points out that two persons can perceive the same object (“hen”) differently, and thus there may be two different appearances of the same object (“dyo gar an eie to hen”). In this case, he says, it is difficult for someone to have exactly the same sense-experience (“tauton”) with somebody else's sense-experience of the same thing (“hoste schole allo pan tauto aisthoito tis”). That is, it is impossible for two persons to have the same experiences, or as Ayer puts it, "one person cannot have the experience of another", a claim which has led philosophers to argue for "the paradoxical view [that] when different people are said to perceive the same physical object, each of them perceives his own sense-data" (Ayer, 1980, p. 202-203).

In this context, it is legitimate to say that for Gorgias the physical thing is one and the same, but it is phenomenally duplicated, or multiplied, by the intervention of our sense-experiences (or sense-impressions). Furthermore, the sense-experiences are so different from person to person that it is difficult (“schole”) for many observers to have exactly the same sense-impression of anything whatsoever (“pan auto”, MXG 980b 17). This, in its turn, shows that one's own sense-experience of a thing is subjective and private to one's self and thus distinct from the thing itself. In this sense, Gorgias deals with the fact that many different people can have different sense-experiences of the same thing. He wants to show that what is one and at the same time two things (“dyo gar an eie to hen”) is the different sense- experiences of two observers looking at the same thing, not the thing itself (“hen”). So, as Ayer would put it:

these objects do not change their perceptible qualities [...] they come to be contrasted with the fluctuating impressions that different observers have of them … in this way the objects are severed from the actual percepts ... and the observers' experiences [...] are taken to be subjective […] So far from being the only things that there are thought to be, they may be denied any independent existence, and treated merely as states of the observer (Ayer, 1991, p. 105).

This difference between people's sense-perceptions is exactly what confirms that every sense-experience of a thing is subjective, private to a perceiver (“hoste schole allo pan tauto aisthoito tis”). So publicity, which is supposed to be the basic feature of physical objects, is not a feature of sensible things (“aistheta”); or, in Ayer's words (1980, p. 85), “sensible things cannot be properly called physical objects”. A physical object has public existence, whereas a sensible thing has no public existence; the latter cannot be identified with the first (Hirst, 1959, p. 37, 46). In this sense, Gorgias has distinguished clearly physical objects from sensible things (“aistheta”). Mourelatos also remarks that Gorgias has distinguished between an external thing and the perception or experience or thought (Mourelatos, 1987, p. 143). Furthermore, Gorgias seems to possess the concept of a mental image which he calls “eikon ton horomenon pragmaton” (“image of the things that are seen”, Hel. 17). Such an image being in our mind (“en to phronemati”, Hel. 17) is distinct from the external things (“pragmata”) represented in our mind (Mourelatos, 1987, p. 145; Mazzara, 1984, p.135-138; Bakaoukas, 2012b).

Gorgias and Aristotle on sense-experience

In other words, Gorgias has shown that (the mode of existence of) sense-experience is ontologically different from (the mode of existence of) a material thing; that is, the material thing is one and the same (“hen”), whereas the sense-experiences of the same thing are as many as the perceivers. To support this conviction Gorgias uses the argument from illusion, the starting point of which, according to Ayer and Gorgias as well "is that objects appear differently to different observers" (Ayer, 1980, p. 87), or that " there is nothing to prevent it from not seeming (“phainesthai”) the same in them all" (MXG 980 b12, transl. Hett, 1936). Furthermore, Gorgias and Aristotle seem to deal with the argument from illusion from the same starting point; they both examine the most usual cases mentioned in arguments from illusion: (a) different observers seeing, hearing, tasting different things and (b) objects appearing differently to the same observer. As regards case (a) Gorgias says: “ouden kolyei me homoion phainesthai autois, me pante homoiois ekeinois ousin kai en to auto topo” (there is nothing to prevent it from not seeming the same in them all, seeing that they are not in every way alike, nor in the same place MXG 980 b12-13 transl. Hett, 1936). Similarly, Aristotle in Metaph. Γ 1009b3-4 mentions: "and that the same thing is thought sweet by some who taste it, and bitter by others" (transl. Ross). As regards case (b), Gorgias says:

But even the man himself does not seem to perceive similar things at the same time, but different things with his hearing and with his vision, and different again at the moment and long ago, so that one man can hardly perceive the same things as another (MXG 980b14-17, transl. Hett)⁴

Similarly, Aristotle in Γ 1009b8-9: “kai auto de hekasto pros auton ou tauta kata ten aisthesin aei dokein” (“and even to the senses of each individual, things do not always seem the same.”, transl. Ross). In case (b), according to Kenny (1967, p. 189), there are things which appear differently to the same man at different times and under different conditions (in Gorgias' case, “nyn te kai palai diaphoros”, and in Aristotle's case, “ou tauta aei”). The difference between Aristotle and Gorgias is that the first gives a few examples of conflicting sense-impressions such as that of the sweet and bitter thing, whereas the latter does not give any instance of it.

But why do Aristotle and Gorgias introduce the argument from illusion? According to Kenny (1967, p 189), Aristotle takes it to be a cause which leads people, and particularly Protagoreans, to believe that whatever appears to anyone is true. For Aristotle, the Protagorean view does not make any sense, since "if every appearance and belief was true, every statement would be both true and false" (Kenny, 1967, p. 184). As an undesirable result the principle of non-contradiction would be violated, and the logical consequence of such a violation would be the following:

[…] which, then, of these impressions are true and which are false is not obvious […] and this is why Democritus, at any rate, says that either there is no truth or to us at least is not evident. (Metaph. Γ 1009b 11-12. transl. Ross)

Interestingly, Gorgias agrees with this Aristotelian view, since, in the context of the argument from illusion, he says that there is nothing evident and true: “ti oun mallon delon ei toiad' esti; poia de talethe adelon” (MXG 980a 17-18) (“why should it be any clearer, if such things exist? But it is quite uncertain which kind of things is true”, transl. Hett, 1936). Moreover, Aristotle holds that such a state of unknowability in which nothing is evidently true or false is the logical consequence of the false belief of some philosophers that "to phainomenon kata ten aisthesin eks anankes alethes einai" (“the impression given through sense-perception is necessarilly true”, 1009b 14, transl. Tredennick, 1938), or that "ta d' onta [hypelabon] einai ta aistheta monon" ([they supposed that] reality is confined to sensible things 1010a 2-3, transl. Tredennick, 1938); a view that is compatible with Gorgias’ thesis that sense-impressions (“aistheta”) are subjective and private to every perceiver (MXG 980b14-17).

According to Kenny (1967, p. 190), Aristotle’s argument in Metaph. 1010 ff. is meant to show that "at least some appearance is false". And to do that, Aristotle employs a view that is used by Gorgias himself, the view that "the sensation is not false of its proper object", which for Aristotle means that colour is the proper object of sight, sound of hearing and flavor of taste (de An. II, 418a 12). That is to say, the senses are infallible about their proper objects. For Aristotle, this infallibility does not mean that the senses are incorrigible, but that they can only be corrected by themselves (“ton idion ai aistheseis eisi kritikai” 1010b 15-18, 1010b 14). Gorgias agrees with these remarks, since he says: (a) “hekaston [sc. aistheton] gar hypo tes idias aistheseos all' ouh hyp'alles opheilei krinesthai” (DK B3 81) (“for each object ouhgt to be judged by its own special sense and not by another.”, transl. Bury, 1935), and (b) “hosper oude he opsis tous phthoggous gignoskei, houtos oude he akoe chromata, alla phthoggous” (MXG 980b 1-2) (“for just as sight is not the sense which recognizes sounds, so hearing cannot hear colours.”, transl. Hett, 1936). For Aristotle, the senses are not infallible, since they are liable to error (“oligiston pseudos”, de An. 428b 18-20). Such error comes about when the sense-organs function under non-standard conditions; that is to say, when the object seen is far away, the perceiver is ill or asleep (Metaph. 1010 b3-11). Under these non-standard conditions two persons being in a different state cannot perceive, let’s say, a white object, since they have different and conflicting sense-impressions (Modrak, 1989, p. 69; Kenny, 1967, p. 194-195). In the same sense, Gorgias, using the argument from illusion, says that nobody can perceive or think the same thing as another (“hoste schole allo pan tauto aisthoito tis”, MXG 980b 16-17; “oudeis heteros hetero tauton ennoei”, 980b 19-20).

It can hardly be a coincidence that Gorgias and Aristotle to this point endorse almost the same treatment of sensible things (“aistheta”). Both of them refer to the proper objects of senses, a fact which may commit Gorgias to the Aristotelian view that "the perception of the proper objects provides the foundation for other types of perception and perception provides the basis for knowledge" (Modrak 1989, p. 79). Aristotle's further criticism of sense-experience accordingly is that the senses can only tell us that “there is a color here” but not, for example, that "this white thing is human" (de An., 430b29), or that something is warm but not why it is warm (Metaph. A981a10-13). That is to say, a judgement based on sense-experience is not "an unqualified judgement of the form "such and such is/will be the case". In other words, the senses are limited to the sensory apprehension of particulars and cannot grasp universals, which is the very characteristic that distinguishes sense-experience from knowledge (Modrak, 1989.p. 167). However, it is not possible for Gorgias to know the notions of universals or platonic ideas, which are still the topic of modern research (Burgin, 2017). The Aristotelian view that Gorgias endorses is that sense-experience is not knowledge, since all senses are limited to the apprehension of sensory particulars (“kath' hekaston”, Metaph. A 981b11) and nothing more.

The relevant Gorgianic view is that aistheta taken as such, if verbalized, cannot describe or represent an external thing (“parastathenai”, DK B3 87; “(an)eksoiston”, 65, 83; “(an)ermeneuton”, 65; “to ektos”, DK B3 86). “Aistheta” or the sensory representation of things, i.e., what Aristotle calls “phantasmata” (Modrak, 1989, p. 167), if verbalised, cannot tell us what is the case for something. They cannot give us information about an external object (“to on ektos”); this is what Gorgias means by saying that “aistheta”, if verbalised, are “aneksoista” and “anermeneuta”; that is, “they cannot convey and tell it to anyone else” (DK B3 65), since the verbal expressions of “aistheta” (as such) do not afford any information or knowledge about any objective state of affairs beyond our experience.

After all, Gorgias' and Aristotle's treatment of sensible things are based on the notion of the proper objects of the senses and perceptual relativity. Consequently, Gorgias seems to have the same intention as Aristotle, i.e., to show that some sensible appearances and beliefs based on them are false and also that such beliefs are not knowledge-adducing. It should be mentioned that Aristotle's account is more sophisticated, complete and clear, whereas Gorgias' account of sense-experience is not so elaborate and complete, owing to the fact that (a) Gorgias, a century before Aristotle, had not a conceptual apparatus as elaborate as the Aristotelian one, and (b) the Gorgianic works survived in the form of incomplete paraphrases.

Sense-experience as such

In the third part of the On What is Not (DK B3 83-87) Gorgias discusses the notion of sensible things (“aistheta”) as such, i.e., sense-experiences alone. In this context, Gorgias, as we saw, has indicated clearly that the same physical things appear differently to humans (“me homoion phainesthai autois”), a fact which shows that people have different sense-experiences of the same thing (“hoste schole allo pan tauto aisthoito tis”). This claim being the starting point of the argument from illusion could not be uttered by Gorgias by chance as it has some interesting philosophical implications. For, he asserts that people's different sense-experiences are due to their being in a different state and place, which seems to be an allusion to perceptual relativity. Things indeed may look different in many ways: a mountain looks small at a distance and bigger when we are close to it; the properties of an object (e.g. colour or form) vary relatively to the medium existing between us and it, to our vantage point, to the state of our health, body, sense-organs, etc. (Hirst, 1959, p. 4). Another interesting implication deriving from the text itself is that one physical thing that is independently existing (“to on ektos”, DK 85, 86) is one and the same in itself (“hen”), but, although it is one, it acquires many appearances, when perceived by many percipients. As Mourelatos put it (1987, p. 146-155), Gorgias deals with the matter of perceptual identity. That is to say, he doubts that different persons can have the same sense-perceptions, since their constitutions and the perceptual conditions are different.

His basic idea, in modern terms, is simple. If one physical object has two different appearances, when perceived by two different persons, then what could explain its phenomenal duplication is the possibility of there being two objects with two different appearances; but this, as he says, is absurd, since the one thing in question would be two different things (“dyo gar an eie to hen”). Therefore, what changes appearances should not be the object itself, but the sensible things (“aistheta”), which vary from man to man. Sensible things are as many as the percipients, they are subjective, private to their owners, and consequently, they cannot be identified with the unique thing. In consequence, our subjective sense-experiences of a single thing and the thing itself are regarded as two separate items. What we experience via our senses is private to us and quite distinct from external objects and others' sense-experiences of them. In this sense, if what is presented to our senses (“aistheta”) is private and subjective, then by modern standards they are unobserved by others, and cannot be like proper physical objects. This means that, for Gorgias, sensible things (unlike physical things), are not publicly perceptible.

Following this line of interpretation, it must be made clear that only sense-experiences, not physical objects themselves, are subjective and private to one observer and different from one perceiver to another. On Gorgias' account, what is presented to one's senses (in seeing one and the same object) is different (“me homoion”) a) from what is presented to others' senses, and b) from this very object; so that our 'sense-presentations' are not in a position to represent in the mind of many observers (“en pleiosi”) one and the same thing (“hen, tauton”) that is observable by many people. As a result, we would not perceive by means of our senses the same physical thing ever; or, in Strawson's more sophisticated terms (1979, p. 53-54), "nothing perceptible is a physically real, independent existence". In other words, if we had to acquire information about the things around us only by means of our senses, then the information acquired would be just a cluster of subjective sense-experiences, viz. what the sight, the hearing and individually every sense grasps. In this case, it would be impossible for two different persons to hear the same sound, to smell the same smell, to taste the same flavor, or to see the same object (“hoste schole allo pan tauto aisthoito tis”). Furthermore, if our knowledge were limited to sensory data, then our knowledge of everything would be limited only to sensations, i.e., to the apprehension of sensible qualities such us colors (“chromata”, MXG 980b3) or sounds (“phthoggous” MXG ibid.). In Aristotelian terms, our epistemic capacity would be limited to the apprehension of sensory data and we would not be able to apprehend concrete particulars such as people, trees and concrete situations such as "a white man is leaving" (Modrak, 1989, p. 99). As a result, the sensory data as such (“aistheta”), i.e., our sense-experiences, if verbalized, are not knowledge of a concrete object (“hen”) or a concrete state of affairs. Let us keep in mind that Gorgias' basic premise is that "if something exists, we cannot know it", and that he searches for the reason why this may be so. It follows that the aforementioned cognitive incapacity of the senses, due to their subjectivity, is one of the causes of unknowability, as asserted by Gorgias.

On things-thought-about

Gorgias also distinguishes clearly sense from thought and considers them both to be distinct faculties. The second part of the On What is Not treats of the very nature of pure thought (“dianoeisthai”, MXG 980b7).⁵ In the third part, as we have seen, Gorgias, using the argument from illusion, drew a delicate distinction between material things and the corresponding sensible things (“aistheta”). In the same context, here, he tries to distinguish material things from the corresponding things-thought-about (“ha dianooumetha”). He believes that there are thoughts, concepts, which are ontologically distinct, or different from, material things. For this reason, he emphasizes the fact that our thinking at any moment can be ontologically independent of the putative material thing we think of. Hence, says Gorgias, we can think of non-existent things like flying chariots (MXG 980b11-12) or chimera (DK B3 80).

As Schiappa (1994, p. 158) and Barnes (1993, p. 171) point out, for Gorgias things-thought-about like chimera cannot be identified with things-that-are. According to Gorgias, in thinking of non-entities there is not any perceptual connection between us and the external world. Thus, hypothetically speaking, if there was no perceptual connection between us and the extramental world at all, everyone, says Gorgias, could think and assert whatever he wanted, even the most absurd lie, without anyone being able to contradict him. In Gorgias’ words:

But, if this is so, no one, he says, could say anything false, not even if he said that chariots compete in the sea […] and because no one thinks the same things as another. (transl. Hett, 1936).⁶

So, if our understanding were limited only to things-thought-about, there would be no extramental criterion by reference to which we could discern the extramental from the mental world, the truth from the falsehood, the being from the nonbeing. As a result, in Gorgias' terms, "why should it be any clearer, if such things [sc what we see and think] exist? But it is quite uncertain which kind of things is true" (“ti oun mallon delon ei toiad' esti; poia de talethe adelon”, MXG 980a 16-18, transl. Hett, 1936).

In other words, Gorgias notices the subjectivity of thoughts (conceptual relativity) as he did for the subjectivity of sense-experiences (perceptual relativity). As regards the subjectivity of sense-experiences, he said that "one man can hardly perceive the same things as another" (MXG 980b 16-17). As regards the subjectivity of thoughts, he says that “no one thinks the same things as another" (MXG 980b19).

Sense-experiences, thoughts and knowledge

Gorgias so far has dealt with sense-experiences and thoughts as not concurrent with one another. He claims that our sense-experiences as such (“ha horomen”) and our thoughts as such (“ha dianooumetha”), being private and subjective, are not a ground for knowing things. Therefore, nothing could be known and thus described or made known to others (“agnoston”, DK B3 77; “aneksoiston kai anermeneuton to pelas”, DK B3 65). He agrees with Aristotle that “ou pan to phainomenon alethes” (the impression given through sense-perception is not necessarily true, Metaph. 1010b1-2) and, also, he does not take sense-experience to be knowledge. As regards thought (“dianoeisthai”) he also agrees with Aristotle in that thought can be erring and false (“dianoeisthai d'endechetai kai pseudos”, de An. 427b13). The error of thought is detected by Gorgias in verbalizing our thoughts and beliefs: "one could say something false... if he said that chariots compete in the sea"(“an eipoi pseudos […] ei en to pelagei phaie hamillasthai harmata” MXG 980 a 10-12, transl. Hett, 1936). Similarly, Aristotle attributes the error of thought to (verbal) beliefs which being "a function of the noetic faculty can be false" (Modrak, 1989, p. 129).⁷ Not all thinking is knowledge, since the formation of opinion which is thinking, though based on knowledge, is not necessarily knowing (Wilson, 1967, p. 18).

Furthermore, according to Gorgias, if thought has not any causal, perceptual relation to extramental world, it cannot be knowledge-adducing, for in that case it is subjective and private to its owner. So, to a certain extent, he identifies private and subjective thought with what Aristotle calls “phantasia” or “phantastikon”, i.e., "the awareness of a sensory content under conditions that are not conducive to veridical perception" (Modrak, 1989, p. 82).⁸ That is to say, Gorgias' private and subjective thought is an Aristotelian case of non-veridical perception which is an internal mental representation of sensible things (“aistheta”) without an external stimulus (Modrak, 1989, p. 83). This is a case of an Aristotelian case of dreaming or “phantasia” (Modrak, 1989, p. 85).⁹ Gorgias would agree with Dretske's view that "to dream (or imagine) one flying to moon is not to fly to a dream (or an imaginary moon)" (Dretske, 1969, p. 46). In the same sense, Gorgias says that to think or imagine chariots running over the sea is not to actually perceive or observe such imaginary chariots (DK B3 82).¹⁰ In this example, Gorgias presents thought as having no causal, perceptual relation to an external thing (“to ektos”). That is to say, he takes thought to be a non-perceptual experience.

From a philosophical point of view, if we base our knowledge of physical objects on sense-experiences and thoughts, we are bound to the egocentric outlook or predicament (Saunders 1967: 13-20); that is, we cannot know that something exists independently of our own private experiences. We do not know how to get out of our own private experiences to physical things. In a way, we are led to agnostic solipsism; we are incapable of knowing whether physical objects exist. For Gorgias what comes out of it is an unknowability (“ou gnoston”). Nonetheless, he is not a sceptic or an agnostic, since he believes that we can know things by virtue of a causal perceptual mechanism which is called by him consciousness (“syneidenai, eidenai akribos”).

To be more specific, in the Palamedes Gorgias makes it clear that we can know things. First, this is implied by the cognitive terms he uses: “saphos epistamenos” (3), “saphos oida, synoida gar emauto saphos” (5), “synepistanto” (21). As he puts it, I get to know something when I pay attention to the facts (“tois ergois prosechein ton noun”, 34), and the way of doing it is through experience (“peira”) (34). So he speaks about empirical knowledge about facts; he accepts that there is truth of facts (“ten aletheian ton ergon”, 35). The way we know things and facts is purely perceptual or experiential; i.e., either by being an eyewitness or by proof by eyewitness: “oistha idon e metechon e tou metechontos pythomenos” (22), that is, you know (sc. a fact) either because you saw it, or because you participated, or you got information from a participant. Always there is a reported fact occurring in a particular manner, in a specific place and at a definite time. In his own words, “if you saw it, tell them the manner, the place, the time; when, where, how you saw it” (“ei men oun idon, phrason toutois ton tropon, ton topon, ton chronon, pote, pou, pos eides”, 22). So, according to Gorgias, knowledge or information about a fact can be conveyed and subsequently acquired. Such knowledge or reliable information about a particular fact is that which the judges lack, for they do not have any perceptual connection with the fact. But, as Gorgias says, the judges can turn their attention to the facts and the eyewitness's experience (“peira”). So, as it appears, Gorgias adopts a perceptual knowledge of facts.

Indeed, Gorgias says that "so deeply does sight engrave on the mind images of actions that are seen" (Hel. 17). This seems to imply that we may see images and not things directly. But Gorgias does not say anywhere that we see images; what we really see are things, facts or actions (“ton horomenon pragmaton”, Hel. 17). Nevertheless, according to Gorgias, we do have images in our mind (“en to phronemati”, Hel. 17) when we see things. This, however, does not exclude the possibility of seeing things directly, for mental images ("eikones") are caused by seeing things (not just images). When we have images in our mind, we still see the things the images represent, not the images themselves. In Gorgias' terms, we see the things represented “hoiaper horomena”, i.e., as being seen in reality (Hel. 17).¹¹

Conclusion: discourse on private/subjective experiences is not informative

As we have seen, Gorgias made use of the argument from illusion to show that sense-experiences and thoughts are different from material objects. In a sense, he showed that our experience in general has a different mode of existence from that of material things. What he inferred from the argument from illusion is the existence of human experience as distinct from material objects. In a same vein, mutatis mutandis, Ayer inferred from the same argument the existence of sense-data. So, Gorgias uses the argument successfully. In modern terms, he manages to show that our sensory experience has a phenomenological core which can be identified independently of any reference to existent physical objects. In other words, he refers to the phenomenological content of our sensory experience which occurs although there is not any present physical object to be perceived (Burkhardt, 1991, p. 690-691). Consequently, he deals with a sort of phenomenal experience that is distinct from, or independent of, any material thing. Such an experience is private and subjective insofar as "the subjective cases are private, or in so far as the public is objective and the private subjective (Quinton, 1952, p. 237; Britton, 1952, p. 201-202).

In other words, Gorgias deals with the antithesis between the private and the public (or between the subjective and the objective); this is shown by the fact that he refers to what, according to Ayer (1991, p. 94), are two characteristics of this very antithesis: a) "the different persons" (“me pante homoiois ekeinois ousin”) and b) the distinction between "their inner experiences" (“ha horomen he dianooumetha”) and the "external objects which they perceive in common" (“to on ektos”). In other words, Gorgias distinguishes the "objects" from "our experiences of objects", a fact which shows that mutatis mutandis he may have anticipated the distinction between the mental and the physical. According to Hacker (1972, p. 223-224), such a distinction makes "a misguided metaphysics" - which is Wittgenstein's target - "to view the mental as the only real, knowable world". In the case of Gorgias, I have identified such a kind of mental world with non-perceptual, private, subjective or phenomenal experience that Gorgias examines critically. He considers that non-perceptual, subjective, phenomenal experience as such, if verbalized, is not knowledge (“ou gnoston”), in the sense that it is not "any kind of factual information about something beyond the experience".

According to this Gorgianic argument, there is a problematic verbal expression (“logos”) for putting into words our sense-perceptions and thoughts. As Gorgias put it:

[…] it cannot be demonstrated to others […] (MXG 979a 13-14, transl. Hett, 1936)¹²

[…] how, he says, could anyone communicate them to another? For how could a man express in words what he has seen? (MXG 980a 19-22, transl. Hett, 1936)¹³

[…] anything, then, which a man has not in his consciousness, how can he acquire it from the word of another, or by any sign which is different from the thing? (MXG 980b3-5, transl. Hett, 1936)¹⁴

[…] how can the hearer be conscious of the same thing? (MXG 980b9, transl. Hett, 1936)¹⁵

[…] no one could show it to another […] (MXG 980b 17-18, transl. Hett, 1936)¹⁶

As Lazerowitz (1968, p. 37-39) has pointed out, Gorgias here refers to the incommunicability of private sensations or to a kind of private language which I shall explain after briefly commenting on Ayer's and Wittgenstein's view about private language. Their view will help us to evaluate Gorgias' one without any anachronistic comparison between them.

Ayer's criterion of determining the truth of the "experiential" propositions which communicate our private experiences is the "observer's own experience" and this is so, because, as he says, "we too [sc. the speakers of a public language like the speakers of a private or 'primitive' language] are obliged in the end to rely simply on our power of recognition" (Ayer, 1991, p. 94-95); whereas Wittgenstein's criterion is opposed to Ayer's one to the effect that the observer's experience should be independently checked by something public, which Wittgenstein identifies with the effective public rules of a real language (Pears, 1976, p. 142-167). In other words, Ayer's experiential criterion is opposed to Wittgenstein's "social-linguistic" criterion (Bakaoukas, 2001).

The Gorgianic notion of private language, in its turn, points to the communication of non-perceptual, phenomenal experience. Gorgias, unlike Ayer and Wittgenstein, is not concerned with the question whether private immediate sensations are communicable or not, that is, whether "another person can understand the language" of someone whose language refers "to his immediate private sensations" (Wittgenstein, 1953, §243). He does not seem to be even aware of the question of whether a private language is possible or not. He takes for granted that language as a vehicle of thoughts and sense-experiences is possible (Untersteiner, 1954, p. 156-158) and asks the following questions. Is a language that conveys the subjective, non-perceptual, phenomenal experience of ours (“ha horomen he dianooumetha”) a possible communication of matters of fact? That is to say, can such a language manage to inform us of something beyond our experience? His view is that in verbally communicating our (phenomenal) non-perceptual experience we do not actually formulate a material object-statement or description which can give us (“ekpherein”) reliable information about an external object or event (“to ektos”). In that case, for Gorgias, “logos de ouk esti ta hypokeimena kai onta” (“speech is not the real and existent things”, DK B3 85, transl. Bury, 1935) or that “ouh ho logos tou ektos parastatikos estin” (it “is not speech that serves to reveal the external object”, DK B3 86, transl. Bury, 1935). That is to say, if there is not any perceptual connection between us and a specific external thing, then our speech or language cannot represent this thing and cannot give us factual information about it (Bakaoukas, 2001).

I shall use a judiciary example that falls within Gorgias' interests, that is the judges referred to in the Palamedes: "an eyewitness can tell what occurred, whereas the jurymen [Socrates refers to] only think what occurred. Of course, they can put into words what they think, but in doing so, they could not tell us what occurred" (Ryle, 1990, p. 29). The judges lack a perceptual connection with the event. They need the evidence (of the senses) of an eyewitness in order to judge what is the case. Or, as Aristotle would put it, the judges exercise their “logistike” or “bouleutike phantasia”, i.e., they exercise their reasoning on the basis of sufficient or insufficient evidence. If there is insufficient or misleading evidence, their judgement could be wrong (Modrak, 1989, p. 100, n. 72). Hence, if the judges’ thought or reasoning has not any perceptual connection with an event for lack of eyewitnesses, then the judges’ decision would not be grounded on facts. On the contrary, the eyewitness' testimony is grounded on facts, for an eyewitness has the appropriate perceptual connection with the event. So an eyewitness, contrary to the judges, can report and describe what actually happened. Therefore, his testimony being informative manages to be about something (MacDowell, 1978, p. 235). In Gorgias’ terms, the eyewitness' speech (“logos”) manages to be “parastatikos tou ektos”, so that it can reveal or describe verbally (“ekpherein, hermeneuein”) an event or a state of affairs outside us (“to ektos”).

Furthermore, for Gorgias, our experiences are distinct from the material objects which they are supposed to represent (“parastathenai”). This sort of experience mutatis mutandis is like an Aristotelian phantasma, i.e. just a sensory representation of an object (Modrak, 1989, p. 167), or a Platonic image (“eidolon”) which, to the Eleatic stranger, is not the real being (“alethinon or “ontos on”, Sph. 240a9-b2). But, if an image, in the case of Gorgias' “eikon” (Mazzara, 1984, p. 136), is not a real being (“ouk ontos on”, Sph. 240b6), what is it? For Gorgias, as we saw, such sensory experiences or images, being as many as the percipients, are to be identified with phenomenal experiences and mental images. These experiences and images are different from (“me homoion”) the external object (“hen”) they are supposed to represent (Bakaoukas, 2012a).

So, on the one hand, there are the objects (“pragmata”) to be represented, and, on the other hand, the representations of these objects (“eikones ton horomenon pragmaton”). These representations can be considered as the phenomenological content of our experience or as mental images. Following Quinton (1952, p. 246, 251), it is one thing to describe our experience phenomenologically and another thing to describe material things while having an experience: the first description is what Gorgias refers to as a case of 'non-informative' communication (“logos ouk parastatikos tou ektos”). So, in uttering such a logos we do not give any information about a matter of fact beyond our phenomenal experience; or, as Quinton puts it in modern terms,

So, even if we could derive material thing statements by inference from the given [...] [in order that out descriptions of appearance shall be informative (1952, p. 246)] […] we do not in fact do so. (1952, p. 251)

In other words, "a phenomenological description of my immediate experience" present to my sense-field is not a description of a public, physical thing; whereas in a perceptual situation a description of a thing is about a public, material thing (Quinton, 1973, p. 180, 184, 190). In this sense, we can say that for Gorgias what is knowable (“gnoston”) is a physically present thing when perceived and not a phenomenologically present thing in a non-perceptual experience such as the imaginary chariots running over the sea or chimera.¹⁷

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• 1
  The private and the subjective are considered here to be synonymous; that is, "the subjective cases are 'private' in the sense that it is not logically possible for me to have the same reasons as you have for saying that something appears to be such-and-such; on the other hand, the objective cases are 'public' in the sense that I can have the same sort of reasons as you for saying the penny appears to be elliptical" (Quinton, 1952, p. 237).
• 2
  “hekaston [aestheton] gar hypo tes idias aestheseos, all' ouh hyp'alles opheilei krinesthai” (DK B3 81) (“For each sensible thing ought to be judged by its own special sense and not by other.”, transl. Bury) or “ta men hopata horasei katalepta esti, ta de akousta akoe kai ouk enallaks” (DK B3 83) (“The visible things are apprehensible by sight and the audible by hearing, and not conversely.”, transl. Bury). These Gorgianic claims mutatis mutandis agree with the following views of Ayer in his Problem of Knowledge (1980, p. 86): "It is true that there is a familiar use of words like 'hear' and 'taste' and 'smell', according to which the objects that are heard or tasted or smelled are private to a single sense. We commonly talk of hearing sounds […]. There are objects, such as mirror images which are private to the sense of sight".
• 3
  “οὐ γὰρ οἷόν τε τὸ αὐτὸ ἅμα ἐν πλείοσι καὶ χωρίς οὖσιν εἶναι· δύο γὰρ ἂν εἴη τὸ ἕν. εἰ δὲ καὶ εἴη, φησίν, ἐν πλείοσι καὶ ταὐτόν, οὐδὲν κωλύει μὴ ὅμοιον φαίνεσθαι αὐτοῖς, μὴ πάντη ὁμοίους ἐκείνοις οὖσιν καὶ ἐν τῷ αὐτῷ· εἰ γάρ τι ἦν τοιοῦτο, εἷς ἄν, ἀλλ’ οὐ δύο εἶεν. φαίνεται δὲ οὐδ’ αὐτὸς αὑτῷ ὅμοια αἰσθανόμενος ἐν τῷ αὐτῷ χρόνῳ, ἀλλ’ ἕτερα τῇ ἀκοῇ καὶ τῇ ὄψει, καὶ νῦν τε καὶ πάλαι διαφόρως, ὥστε σχολῇ ἄλλῳ πᾶν ταὐτὸ αἰσθητὸν τις. οὕτως οὐκ ἔστιν, εἰ ἔστι τι, γνωστόν, ⟨εἰ δὲ γνωστόν,⟩ οὐδεὶς ἂν αὐτὸ ἑτέρῳ δηλώσειεν, διά τε τὸ μὴ εἶναι τὰ πράγματα λόγους, καὶ ὅτι οὐδεὶς [ἕτερον] ἑτέρῳ ταὐτὸν ἐννοεῖ.” (MXG 980b 9-19)
• 4
  φαίνεται δὲ οὐδ᾽ αὐτὸς αὑτῶι ὅμοια αἰσθανόμενος ἐν τῶι αὐτῶι χρόνωι, ἀλλ᾽ ἕτερα τῆι ἀκοῆι καὶ τῆι ὄψει, καὶ νῦν τε καὶ πάλαι διαφόρως, ὥστε σχολῆι ἄλλωι πᾶν ταὐτὸ αἰσθοιτό τις.
• 5
  Scholars treat the Gorgianic notion of thought (“dianoeisthai”) as discursive thinking (Untersteiner, 1954, p. 157, n.95) or as "the mental categories by which we organize cognition" (Walters, 1994, p. 152).
• 6
  εἰ δ’ οὕτως, οὐδὲν ἂν εἴποι ψεῦδος οὐδείς, φησίν, οὐδ’ εἰ ἐν τῷ πελάγει φαίη ἁμιλ- λᾶσθαι ἅρματα. […] καὶ ὅτι οὐδεὶς [ἕτερον] ἑτέρῳ ταὐτὸν ἐννοεῖ.
• 7
  For Aristotle, belief (“doxa”) involves conviction (“pistis”), persuasion (“peithoi”), and persuasive speech (“logos”) (de An. 428a9-14).
• 8
  In the case of Aristotle, the sensory content is called phantasma (Modrak, 1987, p. 167), whereas in the case of Gorgias, mutatis mutandis, is called “aistheton or eikon ton horomenon pragmaton” (Hel. 17).
• 9
  An example of such an experience equivalent to dreaming could be what Aristotle refers to in Metaph. Γ 1010b 10-11:"if in the night, being in fact in Libya, they judge that they are in Athens, they do not go to Odeon". To Kenny (1967, p. 195), "such a man, if he believes that he has just, in a waking moment, found himself at Athens, rushes off Odeonwards, but not if he believes that he has found himself at Athens only in a dream from which he has just awoken". Aristotle describes such an experience as having it under non-standard conditions (e.g., like having a defective, diseased sense or dreaming). To Aristotle, in such conditions, two persons cannot perceive the same thing (Modrak, 1989, p. 69, 85). In the same context, Gorgias like Aristotle says that one person cannot perceive and think the same thing as another. Phantasia, i.e., the sensory representation of an object, which is not “aisthesis” occurs in those non-standard conditions (Modrak, 1989, p. 85, 167).
• 10
  “If then, a man thinks that a chariot is running over the sea, even if he does not behold it he ought to believe that there exists a chariot running over the sea. But it is absurd.”, DK B3 82, (transl. Bury, 1935).
• 11
  According to Melikova-Tolstaja (1935), paragraph 17 of the Hel. contains a Gorgianic theory of vision; a theory which is a really scientific explanation of the process of vision and perception. Gorgias’ interest in perception is relevant to his teacher Empedocles who according to Aristotle took perception and knowledge to be the same (Curd, 2016, p. 38-57).
• 12
  […] ἀλλ᾽ οὐ δηλωτὸν ἄλλοις. (MXG 979a 13-14)
• 13
  […] πῶς ἄν τις, φησί, δηλώσειεν ἄλλωι; ὃ γὰρ εἶδε, πῶς ἄν τις, φησί, τοῦτο εἴποι λόγῳ; ἢ πῶς ἂν ἐκεῖνο δῆλον ἀκού- σαντι γίγνοιτο, μὴ ἰδόντι; (MXG 980a 19-22)
• 14
  “[…] ὃ οὖν τις μὴ ἐννοεῖ, πῶς ἂν αὐτὸ παρ᾽ ἄλλου λόγῳ ἢ σημείῳ τινι, ἑτέρῳ τοῦ πράγματος, ἐννοήσειεν […]” (MXG 980b3-5)
• 15
  “[…] ἀλλὰ πῶς ὁ ἀκούων τὸ αὐτὸ ἐννοήσει;” (MXG 980b9)
• 16
  “[…] οὐδεὶς ἂν αὐτὸ ἑτέρῳ δηλώσειεν [...]” (MXG 980b 17-18)
• 17
  I am indebted to Professor Theodore Scaltsas under the supervision of whom the present argument was articulated. All remaining errors are mine.
• Data Availability
  Not applicable.
• BAKAOUKAS, M. (2025). The Argument from Illusion in Gorgia’s Treatise On What Is Not. Archai 35, e03518.

Edited by

• Editor:
  Gabriele Cornelli

Data availability

Not applicable.

Publication Dates

• Publication in this collection
  20 Oct 2025
• Date of issue
  2025

History

• Received
  13 Jan 2025
• Accepted
  07 July 2025