7 First of all we must define the number of senses borne by the term ‘Sameness’. Sameness would be generally regarded as falling, roughly speaking, into three divisions. We generally apply the term numerically or specifically or generically—numerically in cases where there is more than one name but only one thing, (10) e. g. ‘doublet’ and ‘cloak’; specifically, where there is more than one thing, but they present no differences in respect of their species, as one man and another, or one horse and another: for things like this that fall under the same species are said to be ‘specifically the same’. Similarly, too, those things are called generically the same which fall under the same genus, such as a horse and a man. It might appear that the sense in which water from the same spring is called ‘the same water’ is somehow different and unlike the senses mentioned above: but really such a case as this ought to be ranked in the same class with the things that in one way or another are called ‘the same’ in view of unity of species. (15) For all such things seem to be of one family and to resemble one another. For the reason why all water is said to be specifically the same as all other water is because of a certain likeness it bears to it, (20) and the only difference in the case of water drawn from the same spring is this, that the likeness is more emphatic: that is why we do not distinguish it from the things that in one way or another are called ‘the same’ in view of unity of species. It is generally supposed that the term ‘the same’ is most used in a sense agreed on by every one when applied to what is numerically one. (25) But even so, it is apt to be rendered in more than one sense; its most literal and primary use is found whenever the sameness is rendered in reference to an alternative name or definition, as when a cloak is said to be the same as a doublet, or an animal that walks on two feet is said to be the same as a man: a second sense is when it is rendered in reference to a property, as when what can acquire knowledge is called the same as a man, and what naturally travels upward the same as fire: while a third use is found when it is rendered in reference to some term drawn from Accident, (30) as when the creature who is sitting, or who is musical, is called the same as Socrates. For all these uses mean to signify numerical unity. That what I have just said is true may be best seen where one form of appellation is substituted for another. For often when we give the order to call one of the people who are sitting down, indicating him by name, we change our description, (35) whenever the person to whom we give the order happens not to understand us; he will, we think, understand better from some accidental feature; so we bid him call to us ‘the man who is sitting’ or ‘who is conversing over there’—clearly supposing ourselves to be indicating the same object by its name and by its accident.
8 [103b] Of ‘sameness’ then, as has been said,3 three senses are to be distinguished. Now one way to confirm that the elements mentioned above are those out of which and through which and to which arguments proceed, is by induction: for if any one were to survey propositions and problems one by one, it would be seen that each was formed either from the definition of something or from its property or from its genus or from its accident. (5) Another way to confirm it is through reasoning. For every predicate of a subject must of necessity be either convertible with its subject or not: and if it is convertible, it would be its definition or property, for if it signifies the essence, (10) it is the definition; if not, it is a property: for this was4 what a property is, viz. what is predicated convertibly, but does not signify the essence. If, on the other hand, it is not predicated convertibly of the thing, it either is or is not one of the terms contained in the definition of the subject: and if it be one of those terms, then it will be the genus or the differentia, inasmuch as the definition consists of genus and differentiae; whereas, (15) if it be not one of those terms, clearly it would be an accident, for accident was said5 to be what belongs as an attribute to a subject without being either its definition or its genus or a property.
9 Next, then, we must distinguish between the classes of predicates in which the four orders in question are found. (20) These are ten in number: Essence, Quantity, Quality, Relation, Place, Time, Position, State, Activity, Passivity. For the accident and genus and property and definition of anything will always be in one of these categories: for all the propositions found through these signify either something’s essence or its quality or quantity or some one of the other types of predicate. (25) It is clear, too, on the face of it that the man who signifies something’s essence signifies sometimes a substance, sometimes a quality, sometimes some one of the other types of predicate. For when a man is set before him and he says that what is set there is ‘a man’ or ‘an animal’, (30) he states its essence and signifies a substance; but when a white colour is set before him and he says that what is set there is ‘white’ or is ‘a colour’, he states its essence and signifies a quality. Likewise, also, if a magnitude of a cubit be set before him and he says that what is set there is a magnitude of a cubit, he will be describing its essence and signifying a quantity. Likewise, also, (35) in the other cases: for each of these kinds of predicate, if either it be asserted of itself, or its genus be asserted of it, signifies an essence: if, on the other hand, one kind of predicate is asserted of another kind, it does not signify an essence, but a quantity or a quality or one of the other kinds of predicate. Such, then, and so many, are the subjects on which arguments take place, and the materials with which they start. [104a] How we are to acquire them, and by what means we are to become well supplied with them, falls next to be told.
10 First, then, a definition must be given of a ‘dialectical proposition’ and a ‘dialectical problem’. For it is not every proposition nor yet every problem that is to be set down as dialectical: for no one in his senses would make a proposition of what no one holds, (5) nor yet make a problem of what is obvious to everybody or to most people: for the latter admits of no doubt, while to the former no one would assent. Now a dialectical proposition consists in asking something that is held by all men or by most men or by the philosophers, i. e. either by all, or by most, or by the most notable of these, (10) provided it be not contrary to the general opinion; for a man would probably assent to the view of the philosophers, if it be not contrary to the opinions of most men. Dialectical propositions also include views which are like those generally accepted; also propositions which contradict the contraries of opinions that are taken to be generally accepted, (15) and also all opinions that are in accordance with the recognized arts. Thus, supposing it to be a general opinion that the knowledge of contraries is the same, it might probably pass for a general opinion also that the perception of contraries is the same: also, supposing it to be a general opinion that there is but one single science of grammar, it might pass for a general opinion that there is but one science of flute-playing as well, whereas, if it be a general opinion that there is more than one science of grammar, it might pass for a general opinion that there is more than one science of flute-playing as well: for all these seem to be alike and akin. (20) Likewise, also, propositions contradicting the contraries of general opinions will pass as general opinions: for if it be a general opinion that one ought to do good to one’s friends, it will also be a general opinion that one ought not to do them harm. Here, that one ought to do harm to one’s friends is contrary to the general view, and that one ought not to do them harm is the contradictory of that contrary. (25) Likewise also, if one ought to do good to one’s friends, one ought not to do good to one’s enemies: this too is the contradictory of the view contrary to the general view; the contrary being that one ought to do good to one’s enemies. Likewise, also, in other cases. Also, on comparison, it will look like a general opinion that the contrary predicate belongs to the contrary subject: e. g. if one ought to do good to one’s friends, (30) one ought also to do evil to one’s enemies. It might appear also as if doing good to one’s friends were a contrary to doing evil to one’s enemies: but whether this is or is not so in reality as well will be stated in the course of the discussion upon contraries.6 Clea
rly also, all opinions that are in accordance with the arts are dialectical propositions; for people are likely to assent to the views held by those who have made a study of these things, (35) e. g. on a question of medicine they will agree with the doctor, and on a question of geometry with the geometrician; and likewise also in other cases.
11 [104b] A dialectical problem is a subject of inquiry that contributes either to choice and avoidance, or to truth and knowledge, and that either by itself, or as a help to the solution of some other such problem. It must, moreover, be something on which either people hold no opinion either way, or the masses hold a contrary opinion to the philosophers, or the philosophers to the masses, or each of them among themselves. (5) For some problems it is useful to know with a view to choice or avoidance, e. g. whether pleasure is to be chosen or not, while some it is useful to know merely with a view to knowledge, e. g. whether the universe is eternal or not: others, again, are not useful in and by themselves for either of these purposes, but yet help us in regard to some such problems; for there are many things which we do not wish to know in and by themselves, (10) but for the sake of other things, in order that through them we may come to know something else. Problems also include questions in regard to which reasonings conflict (the difficulty then being whether so-and-so is so or not, there being convincing arguments for both views); others also in regard to which we have no argument because they are so vast, (15) and we find it difficult to give our reasons, e. g. the question whether the universe is eternal or no: for into questions of that kind too it is possible to inquire.
Problems, then, and propositions are to be defined as aforesaid.7 A ‘thesis’ is a supposition of some eminent philosopher that conflicts with the general opinion; e. g. the view that contradiction is impossible, (20) as Antisthenes said; or the view of Heraclitus that all things are in motion; or that Being is one, as Melissus says: for to take notice when any ordinary person expresses views contrary to men’s usual opinions would be silly. Or it may be a view about which we have a reasoned theory contrary to men’s usual opinions, e. g. the view maintained by the sophists that what is need not in every case either have come to be or be eternal: for a musician who is a grammarian ‘is’ so without ever having ‘come to be’ so, (25) or being so eternally. For even if a man does not accept this view, he might do so on the ground that it is reasonable.
Now a ‘thesis’ also is a problem, though a problem is not always a thesis, inasmuch as some problems are such that we have no opinion about them either way. (30) That a thesis, however, also forms a problem, is clear: for it follows of necessity from what has been said that either the mass of men disagree with the philosophers about the thesis, or that the one or the other class disagree among themselves, seeing that the thesis is a supposition in conflict with general opinion. Practically all dialectical problems indeed are now called ‘theses’. (35) But it should make no difference whichever description is used; for our object in thus distinguishing them has not been to create a terminology, but to recognize what differences happen to be found between them. [105a]
Not every problem, nor every thesis, should be examined, but only one which might puzzle one of those who need argument, (5) not punishment or perception. For people who are puzzled to know whether one ought to honour the gods and love one’s parents or not need punishment, while those who are puzzled to know whether snow is white or not need perception. The subjects should not border too closely upon the sphere of demonstration, nor yet be too far removed from it: for the former cases admit of no doubt, while the latter involve difficulties too great for the art of the trainer.
12 Having drawn these definitions, (10) we must distinguish how many species there are of dialectical arguments. There is on the one hand Induction, on the other Reasoning. Now what reasoning is has been said before:8 induction is a passage from individuals to universals, e. g. the argument that supposing the skilled pilot is the most effective, (15) and likewise the skilled charioteer, then in general the skilled man is the best at his particular task. Induction is the more convincing and clear: it is more readily learnt by the use of the senses, and is applicable generally to the mass of men, though Reasoning is more forcible and effective against contradictious people.
13 The classes, (20) then, of things about which, and of things out of which, arguments are constructed, are to be distinguished in the way we have said before. The means whereby we are to become well supplied with reasonings are four: (1) the securing of propositions; (2) the power to distinguish in how many senses a particular expression is used; (3) the discovery of the differences of things; (4) the investigation of likeness. (25) The last three, as well, are in a certain sense propositions: for it is possible to make a proposition corresponding to each of them, e. g. (1) ‘The desirable may mean either the honourable or the pleasant or the expedient’; and (2) ‘Sensation differs from knowledge in that the latter may be recovered again after it has been lost, (30) while the former cannot’; and (3) ‘The relation of the healthy to health is like that of the vigorous to vigour’. The first proposition depends upon the use of one term in several senses, the second upon the differences of things, the third upon their likenesses.
14 Propositions should be selected in a number of ways corresponding to the number of distinctions drawn in regard to the proposition: thus one may first take in hand the opinions held by all or by most men or by the philosophers, (35) i. e. by all, or most, or the most notable of them; or opinions contrary to those that seem to be generally held; and, again, all opinions that are in accordance with the arts. [105b] We must make propositions also of the contradictories of opinions contrary to those that seem to be generally held, as was laid down before. It is useful also to make them by selecting not only those opinions that actually are accepted, but also those that are like these, (5) e. g. ‘The perception of contraries is the same’—the knowledge of them being so—and ‘we see by admission of something into ourselves, not by an emission’; for so it is, too, in the case of the other senses; for in hearing we admit something into ourselves; we do not emit; and we taste in the same way. Likewise also in the other cases. Moreover, all statements that seem to be true in all or in most cases, (10) should be taken as a principle or accepted position; for they are posited by those who do not also see what exception there may be. We should select also from the written handbooks of argument, and should draw up sketchlists of them upon each several kind of subject, putting them down under separate headings, e. g. ‘On Good’, or ‘On Life’—and that ‘On Good’ should deal with every form of good, (15) beginning with the category of essence. In the margin, too, one should indicate also the opinions of individual thinkers, e. g. ‘Empedocles said that the elements of bodies were four’: for any one might assent to the saying of some generally accepted authority.
Of propositions and problems there are—to comprehend the matter in outline—three divisions: for some are ethical propositions, (20) some are on natural philosophy, while some are logical. Propositions such as the following are ethical, e. g. ‘Ought one rather to obey one’s parents or the laws, if they disagree?’; such as this are logical, e. g. ‘Is the knowledge of opposites the same or not?’; while such as this are on natural philosophy, e. g. ‘Is the universe eternal or not?’ Likewise also with problems. (25) The nature of each of the aforesaid kinds of proposition is not easily rendered in a definition, but we have to try to recognize each of them by means of the familiarity attained through induction, examining them in the light of the illustrations given above.
For purposes of philosophy we must treat of these things according to their truth, (30) but for dialectic only with an eye to general opinion. All propositions should be taken in their most universal form; then, the one should be made into many. e. g. ‘The knowledge of opposites is the same’; next, ‘The knowledge of contraries is the same’, and that ‘of relative terms’. In the same way these two should again be divided, as long as division is possible, (35) e. g. the knowledge of ‘good
and evil’, of ‘white and black’, or ‘cold and hot’. Likewise also in other cases.
15 [106a] On the formation, then, of propositions, the above remarks are enough. As regards the number of senses a term bears, we must not only treat of those terms which bear different senses, but we must also try to render their definitions; e. g. (5) we must not merely say that justice and courage are called ‘good’ in one sense, and that what conduces to vigour and what conduces to health are called so in another, but also that the former are so called because of a certain intrinsic quality they themselves have, the latter because they are productive of a certain result and not because of any intrinsic quality in themselves. Similarly also in other cases.
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