[48] Concerning this criterion ¹ the controversy which exists amongst the Dogmatists is fierce and, one may say, unending. We, however,—with a view here also to a systematic treatment,—maintain that inasmuch as Man is, according to them, the criterion ‟By whom” matters are judged, and Man (as they also themselves agree) can have no other instrument by means of which he will be able to judge except sense and intellect, then if we shall show that he is unable to judge by means of either sense alone or intellect alone or both conjoined, we shall have given a concise answer to all the individual opinions; for they can all, as it seems, be referred to these three rival theories.

Let us begin with the senses.

[49] Since, then, some ² assert that the senses have ‟empty” impressions (none of the objects they seem to apprehend having any real existence), and others ³ say that all the objects by which they suppose them to be moved are really existent, and others again ⁴ say that some of the objects are real, some unreal, we shall not know whom we should assent to. For we shall not decide the controversy by sense-perception, since it is regarding this that we are making our inquiry whether it is illusory or apprehends truly, nor yet by anything else, seeing that there does not even exist any other criterion ‟by means of which” one ought to judge, according to the present hypothesis.

[50] So then the question whether the senses have illusory affections or apprehend some real object will be incapable of either decision or apprehension; and there follows the corollary, that we must not attend to sensation alone in our judgement of matters, since regarding it we cannot so much as affirm that it apprehends anything at all.

[51] But let it be granted, by way of concession, that the senses are apprehensive; yet, even so they will not be found any the less unreliable for judging the external real objects. For certainly the senses are affected in diverse ways by external objects—taste, for instance, perceives the same honey now as bitter and now as sweet; and vision pronounces the same colour now blood-red and now white. ⁵

[52] Nay, even smell is not consistent with itself; for certainly the sufferer from headache declares myrrh to be unpleasant, while one who does not so suffer calls it pleasant. And those who are possessed or in a frenzy fancy they hear persons conversing with them whom we do not hear. And the same water seems to those in a fever to be unpleasant because of its excessive heat, but to all others tepid.

[53] Whether, then, one is to call all the appearances true, or some true and some false, or all false, it is impossible to say since we possess no agreed criterion whereby we shall judge the question we are proposing to decide, nor are we even provided with a proof that is true and approved, because we are still in search of the criterion of truth ‟By means of which” the true proof itself ought to be tested.

[54] For these reasons he also who asks us to believe those who are in a natural state, but not those whose disposition is non-natural, will be acting absurdly; for he will not gain credence if he says this without proof, and, for the reasons given above, he will not possess a true and approved proof.

[55] And even were one to concede that the sense- impressions of those in a natural state are reliable, and those of men in a non-natural condition unreliable, even so the judgement of external real objects by means of the senses alone will be found to be impossible. For certainly the sense of sight, even when it is in a natural state, pronounces the same tower ⁶ to be at one time round, at another square; and the sense of taste declares the same food to be unpleasant in the case of those full-fed, but pleasant in the case of those who are hungry;

[56] and the sense of hearing likewise perceives the same sound as loud by night but as faint by day; and the sense of smell regards the same objects as malodorous in the case of most people, but not so in the case of tanners; and the same sense of touch feels warmth in the outer hall, ⁷ when we enter the bath-rooms, but cold when we leave them. Therefore, since even when in a natural state the senses contradict themselves, and their dispute is incapable of decision, seeing that we possess no accepted criterion by means of which it can be judged, the same perplexities must necessarily follow. Moreover, for the establishment of this conclusion we may derive still further arguments from our previous discussion of the Modes of Suspension. ⁸ Hence it would probably be untrue to say that sense-perception alone is able to judge real external objects.

[57] Let us, then, proceed in our exposition to the intellect. Now those who claim ⁹ that we should attend to the intellect only in our judgement of things will, in the first place, be unable to show that the existence of intellect is apprehensible. For when Gorgias, ¹⁰ in denying that anything exists, denies also the existence of intellect, while some declare that it has real existence, how will they decide this contradiction? Not by the intellect, for so they will be assuming the matter in question; nor yet by anything else, since, as they assert, according to our present assumption there exists nothing else by means of which objects are judged. So then the problem as to whether intellect does or does not exist will not admit of decision or apprehension; and from this it follows, as a corollary, that in the judgement of objects we ought not to attend to the intellect alone, which has not as yet been apprehended.

[58] But let it be granted that the intellect has been apprehended, and let us agree, by way of assumption, that it really exists; I still affirm that it cannot judge objects. For if it does not even discern itself accurately but contradicts itself about its own existence and the mode of its origin and the position in which it is placed, ¹¹ how can it be able to apprehend anything else accurately?

[59] And even if it be granted that the intellect is capable of judging objects, we shall not discover how to judge according to it. For since there exists great divergence in respect of the intellect—for the intellect of Gorgias, according to which he states that nothing exists, is one kind, and another kind is that of Heracleitus, according to which he declares that all things exist, and another that of those who say that some things do and others do not exist—we shall have no means of deciding between these divergent intellects, nor shall we be able to assert that it is right to take this man’s intellect as our guide but not that man’s.

[60] For if we venture to judge by any one intellect, by thus agreeing to assent to one side in the dispute we shall be assuming the matter in question; while if we judge by anything else, we shall be falsifying the assertion that one ought to judge objects by the intellect alone.

[61] Further, we shall be able to show, from the statements made concerning the criterion ‟By whom” (as it is called), that we are unable to discover the intellect that is cleverer than all others; and also that if we should discover the intellect that is cleverer than past and present intellects

[62] we ought not to attend to it, since it is not evident whether yet another intellect may not arise which is cleverer than it; and further, that even if we assume an intellect which none could possibly surpass, we shall not assent to the man who judges by means of it, dreading lest he may put forward some false statement and succeed in persuading us of its truth because he possesses the keenest intellect. Neither, then, by the intellect alone ought we to judge objects.

[63] The only remaining alternative is judgement by means of both senses and intellect. ¹² But this again is impossible; for not only do the senses not guide the intellect to apprehension, but they even oppose it. For it is certain, at any rate, that from the fact that honey appears bitter to some and sweet to others, Democritus declared that it is neither sweet nor bitter, while Heracleitus said that it is both. And the same account may be given of all the other senses and sensibles. Thus, when it starts out from the senses, the intellect is compelled to make diverse and conflicting statements; and this is alien to a criterion of apprehension.

[64] Then there is this also to be said: they will judge objects either by all the senses and by all men’s intellects or by some. But if a man shall say ‟by all,” he will be claiming what is impossible in view of the immense discrepancy which obviously exists amongst the senses and the intellects; and moreover, by reason of the assertion of Gorgias’s intellect that ‟we must not give heed either to sense or to intellect,” the man’s statement will be demolished. And if they shall say ‟by some,” how will they decide that we ought to give heed to these senses and this intellect and not to those, seeing that they possess no accepted criterion by which to judge the differing senses and intellects?

[65] And if they shall say that we will judge the senses and the intellects by the intellect and the senses, they are assuming the matter in question; for what we are questioning is the possibility of judging by means of these.

[66] Another point we must make is this: either one will judge both the senses and the intellects by the senses, or both the senses and the intellects by the intellects, or the senses by the senses and the intellect by the intellects, or the intellects by the senses and the senses by the intellect. If then they shall propose to judge both objects by the senses or by the intellect, they will no longer be judging by sense and intellect but by one of these two, whichever one they may choose, and thus they will be entangled in the perplexities previously mentioned.

[67] And if they shall judge the senses by the senses and the intellects by the intellect, then, since both senses conflict with senses and intellects with intellects, whichever of the conflicting senses they shall adopt for judging the rest of the senses, they will be assuming the matter in question; for they will be adopting one section of the series in dispute, as being already reliable, to decide about the others which, equally with it, are in question.

[68] And the same argument applies to the intellects. And if they shall judge the intellects by the senses, and the senses by the intellect, this involves circular reasoning inasmuch as it is required that the intellects should be judged first in order that the senses may be judged, and the senses be first scrutinized in order that the intellects may be tested.

[69] Since, therefore, criteria of the one species cannot be judged by those of a like species, nor those of both the species by those of one species, nor conversely by those of an unlike species, we shall not be able to prefer intellect to intellect or sense to sense. And because of this we shall have nothing by which to judge; for if we shall be unable to judge by all the senses and intellects, and shall not know either by which of them we ought and by which we ought not to judge, then we shall possess no means by which to judge objects.

Consequently, for these reasons also the criterion ‟By means of which” will have no real existence.