by Aristotle
Again, either the theory is true in all cases, and a thing is both white and not-white, and being and not-being, and all other contradictories are similarly compatible, or the theory is true of some statements and not of others. And if not of [10] all, the exceptions will be agreed upon; but if of all, again either the negation will be true wherever the assertion is, and the assertion true wherever the negation is, or the negation will be true where the assertion is, but the assertion not always true where the negation is. And in the latter case there will be something which fixedly is not, [15] and this will be an indisputable belief; and if non-being is indisputable and knowable, the opposite assertion will be more knowable. But if what it is necessary to deny it is equally necessary to assert, it is either true or not true to separate the predicates and say, for instance, that a thing is white, and again that it is not-white. [20] And if it is not true to apply the predicates separately, our opponent is not really applying them, and nothing at all exists; but how could non-existent things speak or walk, as he does? Also all things will on this view be one, as has been already said, and man and God and trireme and their contradictories will be the same. For if [25] contradictories can be predicated alike of each subject, one thing will in no wise differ from another; for if it differ, this difference will be something true and peculiar to it. And if one may with truth apply the predicates separately, the above-mentioned result follows none the less.
Further, it follows that all would then be right and all would be in error, and [30] our opponent himself confesses himself to be in error.—And at the same time our discussion with him is evidently about nothing at all; for he says nothing. For he says neither ‘yes’ nor ‘no’, but both ‘yes’ and ‘no’; and again he denies both of these and says ‘neither yes nor no’; for otherwise there would already be something definite.—Again, if when the assertion is true, the negation is false, and when this is true, the affirmation is false, it will not be possible to assert and deny the same thing [1008b1] truly at the same time. But perhaps they might say we had assumed the very thing at issue.
Again, is he in error who judges either that the thing is so or that it is not so, and is he right who judges both? If he is not right, what can they mean by saying [5] that the nature of existing things is of this kind? And if he is not right, but more right than he who judges in the other way, being will already be of a definite nature, and this will be true, and not at the same time also not true. But if all are alike both right and wrong, one who believes this can neither speak nor say anything [10] intelligible; for he says at the same time both ‘yes’ and ‘no’. And if he makes no judgement but thinks and does not think, indifferently, what difference will there be between him and the plants?—Thus, then, it is in the highest degree evident that neither any one of those who maintain this view nor any one else is really in this position. For why does a man walk to Megara and not stay at home thinking he [15] ought to walk? Why does he not walk early some morning into a well or over a precipice, if one happens to be in his way? Why do we observe him guarding against this, evidently not thinking that falling in is alike good and not good? Evidently he judges one thing to be better and another worse. And if this is so, he must judge one [20] thing to be man and another to be not-man, one thing to be sweet and another to be not-sweet. For he does not aim at and judge all things alike, when, thinking it desirable to drink water or to see a man, he proceeds to aim at these things; yet he ought, if the same thing were alike man and not-man. But, as was said, there is no [25] one who does not obviously avoid some things and not others. Therefore, as it seems, all men make unqualified judgements, if not about all things, still about what is better and worse. And if this is not knowledge but opinion, they should be all the more anxious about the truth, as a sick man should be more anxious about his health [30] than one who is healthy; for he who has opinions is, in comparison with the man who knows, not in a healthy state as far as the truth is concerned.
Again, however much all things may be so and not so, still there is a more and a less in the nature of things; for we should not say that two and three are equally even, nor is he who thinks four things are five equally wrong with him who thinks [35] they are a thousand. If then they are not equally wrong, obviously one is less wrong and therefore more right. If then that which has more of any quality is nearer to it, [1009a1] there must be some truth to which the more true is nearer. And even if there is not, still there is already something more certain and true, and we shall have got rid of the unqualified doctrine which would prevent us from determining anything in our thought. [5]
5 · Again, from the same opinion proceeds the doctrine of Protagoras, and both doctrines must be alike true or alike untrue. For on the one hand, if all opinions and appearances are true, all statements must be at the same time true and false. For many men hold beliefs in which they conflict with one another, and all think [10] those mistaken who have not the same opinions as themselves; so that the same thing must be and not be. And on the other hand, if this is so, all opinions must be true; for those who are mistaken and those who are right are opposed to one another in their opinions; if, then, reality is such as the view in question supposes, all will be right in their beliefs. Evidently, then, both doctrines proceed from the same way of [15] thinking.
But the same method of discussion must not be used with all opponents; for some need persuasion, and others compulsion. Those who have been driven to this position by difficulties in their thinking can easily be cured of their ignorance; for it is not their expressed argument but their thought that one has to meet. But those [20] who argue for the sake of argument can be convinced only by emending the argument as expressed in words.
Those who really feel the difficulties have been led to this opinion by observation of the sensible world. They think that contradictions or contraries are true at the same time, because they see contraries coming into existence out of the same thing. If, then, that which is not cannot come to be, the thing must have [25] existed before as both contraries alike, as Anaxagoras says all is mixed in all, and Democritus too; for he says the void and the full exist alike in every part, and yet one of these is being, and the other non-being. To those, then, whose belief rests on these [30] grounds, we shall say that in a sense they speak rightly and in a sense they err. For ‘that which is’ has two meanings, so that in some sense a thing can come to be out of that which is not, while in some sense it cannot, and the same thing can at the same time be and not be—but not in the same respect. For the same thing can be potentially at the same time two contraries, but it cannot actually. And again we [35] shall ask them to believe that among existing things there is another kind of substance to which neither movement nor destruction nor generation at all belongs.
And similarly some have inferred from the sensible world the truth of [1009b1] appearances. For they think that the truth should not be determined by the large or small number of those who hold a belief, and that the same thing is thought sweet by some who taste it, and bitter by others, so that if all were ill or all were mad, and only two or three were well or sane, these would be thought ill and mad, and not the [5] others. And again, many of the other animals receive impressions contrary to ours; and even to the senses of each individual, things do not always seem the same. Which, then, of these impressions are true and which are false is not obvious; for the one set is no more true than the other, but both are alike. And this is why [10] Democritus, at any rate, says that either there is no truth or to us at least it is not evident. And in general it is because these thinkers suppose knowledge to be sensation, and this to be a physical alteration, that they say that what appears to our [15] senses must be true; for it is for these reasons that Empedocles and Democritus and, one may almost say, all the others have fallen victims to opinions of this sort. For Empedocles says that when men change their condition they change their knowledge;
For wisdom increases in men according to their present state
[20] And elsewhere h
e says:
So far as their nature changes, so far to them always
Come changed thoughts into mind.
And Parmenides also expresses himself in the same way:
For as in each case the much-bent limbs are composed,
So is the mind of men; for in each and all men
Tis one thing thinks—the substance of their limbs:
[25] For that of which there is more is thought.
A saying of Anaxagoras to some of his friends is also related,—that things would be for them such as they supposed them to be. And they say that Homer also evidently had this opinion, because he made Hector, when he was unconscious from the blow, [30] lie ‘thinking other thoughts’,—which implies that even those who are bereft of thought have thoughts, though not the same. Evidently, then, if both are forms of thought, the real things also are at the same time so and not so. And it is in this direction that the consequences are most difficult. For if those who have seen most [35] of what truth is possible for us (and these are those who seek and love it most)—if these have such opinions and express these views about the truth, is it not natural that beginners in philosophy should lose heart? For to seek the truth would be to pursue flying game.
[1010a1] But the reason for this opinion is that while these thinkers were inquiring into the truth of that which is, they thought that which is was identical with the sensible world; in this, however, there is largely present the nature of the indeterminate—of that which exists in the peculiar sense which we have explained; and, therefore, [5] while they speak plausibly, they do not say what is true. For it befits us to put the matter so rather than as Epicharmus put it against Xenophanes. And again, they held these views because they saw that all this world of nature is in movement, and that about that which changes no true statement can be made; at least, regarding that which everywhere in every respect is changing nothing could truly be affirmed. [10] It was this belief that blossomed into the most extreme of the views above mentioned, that of the professed Heracliteans, such as was held by Cratylus, who finally did not think it right to say anything but only moved his finger, and criticized Heraclitus for saying that it is impossible to step twice into the same river; for he thought one could not do it even once.
But we shall say in answer to this argument also, that there is some real sense [15] in their thinking that the changing, when it is changing, does not exist. Yet it is after all disputable; for that which is losing a quality has something of that which is being lost, and of that which is coming to be, something must already be. And in general if a thing is perishing, there will be present something that exists; and if a thing is [20] coming to be, there must be something from which it comes to be and something by which it is generated, and this process cannot be ad infinitum. But leaving these arguments, let us insist on this, that it is not the same thing to change in quantity and in quality. Grant that in quantity a thing is not constant; still it is in respect of its form that we know each thing.—And again, it would be fair to criticize those [25] who hold this view for asserting about the whole material universe what they saw only in a minority even of sensible things. For only that region of the sensible world which immediately surrounds us is always in process of destruction and generation; but this is—so to speak—not even a fraction of the whole, so that it would have been [30] juster to acquit this part of the world because of the other part, than to condemn the other because of this. And again, obviously we shall make to them also the same reply that we made before; we must show them and persuade them that there is something whose nature is changeless. Indeed, from the assertion that things at the [35] same time are and are not, there follows the assertion that all things are at rest rather than that they are in movement; for there is nothing into which they can change, since all attributes belong already to all subjects.
Regarding the nature of truth, we must maintain that not everything which [1010b1] appears is true. Firstly, even if sensation—at least of the object special to the sense in question—is not false; still appearance is not the same as sensation.—Again, it is fair to express surprise at our opponents for raising the question whether magnitudes are as great, and colours are of such a nature, as they appear to people at a [5] distance, or as they appear to those close at hand, and whether they are such as they appear to the sick or to the healthy, and whether those things are heavy which appear so to the weak or those which appear so to the strong, and whether truth is what appears to the sleeping or to the waking. For obviously they do not think these [10] to be open questions; no one, at least, if when he is in Libya he fancies one night that he is in Athens, straightway starts for the Odeum. And again with regard to the future, as Plato says, surely the opinion of the physician and that of the ignorant man are not equally weighty, for instance, on the question whether a man will get well or not.—And again, among sensations themselves the sensation of a foreign [15] object and that of the special object, or that of a kindred object and that of the object of the sense in question, are not equally authoritative, but in the case of colour, sight, not taste, has the authority, and in the case of flavour, taste, not sight; each of which senses never says at the same moment of the same object that it at the same time is so and not so.—But not even at different moments does one sense [20] disagree about the quality, but only about that to which the quality belongs. I mean, for instance, the same wine might seem, if either it or one’s body changed, at one time sweet and at another time not sweet; but at least the sweet, such as it is when it exists, has never yet changed, but one is always right about it, and that which is to [25] be sweet must of necessity be of such and such a nature. Yet all these views destroy this distinction, so that as there is no substance of anything, so nothing is of necessity; for the necessary cannot be in this way and also in that, so that if anything is of necessity, it will not be both so and not so.
[30] And, in general, if only the sensible exists, there would be nothing if animate things were not; for there would be no faculty of sense. The view that neither the objects of sensation nor the sensations would exist is doubtless true (for they are affections of the perceiver), but that the substrata which cause the sensation should [35] not exist even apart from sensation is impossible. For sensation is surely not the sensation of itself, but there is something beyond the sensation, which must be prior [1011a1] to the sensation; for that which moves is prior in nature to that which is moved, and if they are correlative terms, this is no less the case.
6 · There are, both among those who have these convictions and among those who merely profess these views, some who raise a difficulty by asking, who is the [5] judge of the healthy man, and in general who is likely to judge rightly on each class of questions. But such inquiries are like puzzling over the question whether we are now asleep or awake. And all such questions have the same meaning. These people demand that a reason shall be given for everything; for they seek a starting-point, [10] and they wish to get this by demonstration, while it is obvious from their actions that they have no conviction. But their mistake is what we have stated it to be; they seek a reason for that for which no reason can be given; for the starting-point of demonstration is not demonstration.
These, then, might be easily persuaded of this truth, for it is not difficult to [15] grasp; but those who seek merely compulsion in argument seek what is impossible; for they demand to be made to contradict themselves, while they are contradicting themselves from the very first.—But if not all things are relative, but some exist in their own right, not everything that appears will be true; for that which appears [20] appears to some one; so that he who says all things that appear are true, makes all things relative. And, therefore, those who ask for an irresistible argument, and at the same time demand to be called to account for their views, must guard themselves by saying that the truth is not that what appears exists, but that what appears exists for him to whom it appears, and when, and in the sense in which, and in the way in which it appears. And if they give an
account of their view, but do not [25] give it in this way, they will soon find themselves contradicting themselves. For it is possible that a thing may for the same man appear as honey to the sight, but not to the taste, and that, as we have two eyes, things may not appear the same to each, if the eyes are unlike. For to those who for the reasons named above say that what [30] appears is true, and therefore that all things are alike false and true, for things do not appear either the same to all men or always the same to the same man, but often have contrary appearances at the same time (for touch says there are two objects when we cross our fingers, while sight says there is one),—to these we shall say ‘yes, but not to the same sense and in the same part of it and in the same way and at the same time’, so that what appears is under these qualifications true. But perhaps for [1011b1] this reason those who argue thus not because they feel a difficulty but for the sake of argument, should say that this is not true, but true for this man. And as has been already said, they must make everything relative—relative to thought and perception, [5] so that nothing either has come to be or will be without some one’s first thinking so. But if things have come to be or will be, evidently not all things will be relative to opinion.—Again, if a thing is one, it is in relation to one thing or to a definite number of things; and if the same thing is both half and equal, still the equal is not correlative to the double. In relation to that which thinks, then, if the same thing is a man, and is that which is thought, that which thinks will not be a [10] man, but only that which is thought. Again, if each thing is to be relative to that which thinks, that which thinks will be relative to an infinity of specifically different things.