Note on the Text
This treatise survives only in paraphrase, in the writing of Sextus Empiricus, a Roman era philosopher. Sextus was writing in opposition to the Logicians who denied or problematized the criterion of truth.1
On the Negative
[2.1.65] Gorgias of Leontini belonged to the same party as those who abolish the criterion, although he did not adopt the same line of attack as Protagoras.
For in his book entitled Concerning the Non-existent or Concerning Nature he tries to establish successively three main points—firstly, that nothing exists; secondly, that even if anything exists it is inapprehensible by man; thirdly, that even if anything is apprehensible, yet of a surety it is inexpressible and incommunicable to one’s neighbour. [66] Now that nothing exists, he argues in the following fashion: If anything exists, either it is the existent that exists or the non-existent, or both the existent and the non-existent exist. But neither does the existent exist, as he will establish, nor the non-existent, as he will demonstrate, nor both the existent and the non-existent, as he will also make plain. Nothing, therefore, exists. Now the non-existent does not67 exist. [67] For if the non-existent exists, it will at one and the same time exist and not exist; for in so far as it is conceived as non-existent it will not exist, but in so far as it is non-existent it will again exist. But it is wholly absurd that a thing should both exist and exist not at one and the same time. Therefore the non-existent does not exist. Moreover, if the non-existent exists, the existent will not exist; for these are contrary the one to the other, and if existence is a property of the non-existent, non-existence will be a property of the existent. But it is not the fact that the existent does not exist; neither, then, will the non-existent exist.
[68] Furthermore, the existent does not exist either. For if the existent exists, it is either eternal or created or at once both eternal and created; but, as we shall prove, it is neither eternal nor created nor both; therefore the existent does not exist. [69] For if the existent is eternal (the hypothesis we must take first), it has no beginning; for everything created has some beginning, but the eternal being uncreated had no beginning. And having no beginning it is infinite. And if it is infinite, it is nowhere. For if it is anywhere, that wherein it is is different from it, and thus the existent, being encompassed by something, will no longer be infinite; for that which encompasses is larger than that which is encompassed, whereas nothing is larger than the infinite; so that the infinite is not anywhere. [70] Nor, again, is it encompassed by itself. For, if so, that wherein it is will be identical with that which is therein, and the existent will become two things, place and body (for that wherein it is is place, and that which is therein is body). But this is absurd; so that the existent is not in itself either. Consequently, if the existent is eternal it is infinite, and if it is infinite it is nowhere, and if it is nowhere it does not exist. So then, if the existent is eternal, it is not even existent at all.
[ 71] Nor, again, can the existent be created. For if it has been created, it has been created either out of the existent or out of the non-existent. But it has not been created out of the existent; for if it is existent it has not been created but exists already; nor out of the non-existent; for the non-existent cannot create anything because what is creative of anything must of necessity partake of real existence. Neither, then, is the existent created.
[72] In the same way, it is not both together—at once eternal and created; for these are destructive the one of the other, and if the existent is eternal it has not been created, while if it has been created it is not eternal. So then, if the existent is neither eternal nor created nor both at once, the existent will not exist.
[73] Moreover, if it exists, it is either one or many; but, as we shall show, it is neither one nor many; therefore the existent does not exist. For if it is one, it is either a discrete quantitya or a continuum or a magnitude or a body. But whichever of these it be, it is not one; but if it be a discrete quantity it will be divided, and if it be a continuum it will be cut in sections; and similarly, if it be conceived as a magnitude it will not be indivisible, while if it is a body it will be threefold, for it will possess length and breadth and depth. But it is absurd to say that the existent is none of these; therefore the existent is not one. Yet neither is it many.[74] For if it is not one, neither is it many; for the many is a sum of the ones, and hence if the one is destroyed the many also are destroyed with it.
[75] Well, then, it is plain from this that neither does the existent exist nor the non-existent exist; and that they do not both exist—both the existent and the non-existent—is easy to prove. For if the non-existent exists and the existent exists, the nonexistent will be identical with the existent so far as regards existing; and for this reason neither of them exists. For it is admitted that the non-existent does not exist; and it has been proved that the existent is identical therewith; therefore it too will not exist. And what is more, if the existent is identical with the76 non-existent, both of them cannot exist; for if the pair of them both exist, there is no identity, and if there is identity, there is no longer a pair. From which it follows that nothing exists; for if neither the existent exists nor the non-existent nor both, and besides these no other alternative is conceived, nothing exists.
[77] In the next place it must be shown that even if anything exists it is unknowable and inconceivable by man. If, says Gorgias, the things thought are not existent, the existent is not thought. And this is logical; for just as, if it is a property of the things thought to be white it would be a property of white things to be thought—so, if it is a property of things thought not to be existent, it will necessarily be a property of things existent not to be thought.
[78] Consequently, this is a sound and consistent syllogism—“If the things thought are not existent, the existent is not thought.” But the things thought (for we must take them first) are not existent, as we shall establish; therefore the existent is not thought. And, in fact, that the things thought are not existent is plain; [79] for if the things thought are existent, all the things thought exist, and in the way, too, in which one has thought them. But this is contrary to sense. For if someone thinks of a man flying or of a chariot running over the sea, it does not follow at once that a man is flying or a chariot running over the sea. So that the things thought are not existent. [80] Furthermore, if the things thought are existent, the nonexistent things will not be thought. For opposites are properties of opposites, and the non-existent is the opposite of the existent; and because of this, if “to be thought” is a property of the existent, “not to be thought” will most certainly be a property of the non-existent. But this is absurd; for Scylla and Chimaera and many non-existent things are thought. Therefore the existent is not thought. [81] And just as the things seen are called visible because of the fact that they are seen, and the audible termed audible because of the fact that they are heard, and we do not reject the visible things because they are not heard, nor dismiss the audible things because they are not seen (for each object ought to be judged by its own special sense and not by another),—so also the things thought will exist, even if they should not be viewed by the sight nor heard by the hearing because they are perceived by their own proper criterion. [82] 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 this is absurd; therefore the existent is not thought and apprehended.
[83] And even if it should be apprehended, it is incommunicable to another person. For if the existent things are objects, externally existing, of vision and of hearing and of the senses in general, and of these the visible things are apprehensible by sight and the audible by hearing, and not conversely,—how, in this case, can these things be indicated to another person? [84] For the means by which we indicate is speech, and speech is not the real and existent things; therefore we do not indicate to our neighbours the existent things but speech, which is other than the existing realities. Thus, just as the visible thing will not become audible, and vice versa, so too, since the existent subsists externally, it will not become our speech; and not being speech it will not be made clear to another person.
[85] Speech moreover, as he asserts, is formed from the impressions caused by external objects, that is to say the sensibles; for from the occurrence of flavour there is produced in us the speech uttered respecting this quality, and by the incidence of colour speech respecting colour. And if this be so, it is not speech that serves to reveal the external object, but the external object that proves to be explanatory of speech. [86] Moreover, it is not possible to assert that speech subsists in the same fashion as the visible and audible things, so that the subsisting and existent things can be indicated by it as by a thing subsisting and existent. For, says he, even if speech subsists, yet it differs from the rest of subsisting things, and the visible bodies differ very greatly from spoken words; for the visible object is perceptible by one sense-organ and speech by another. Therefore speech does not manifest most of the subsisting things, just as they themselves do not make plain one another’s nature.
[87] Such, then, being the difficulties raised by Gorgias, if we go by them the criterion of truth is swept away; for there can be no criterion of that which neither exists nor can be known nor is naturally capable of being explained to another person.