by Aristotle
7 · You should look and see also whether the term defined is applied in consideration of something other than the account given. Suppose (e.g.) a definition [35] of justice as the ability to distribute what is equal. Now it is the man who chooses, rather than the man who is able, to distribute what is equal who is just; so that justice will not be an ability to distribute what is equal; for then also the most just [146a1] man will be the man with the most ability to distribute what is equal.
Moreover, see if the object admits of degrees, whereas what is given by the account does not, or, vice versa, what is given by the account admits of degrees while [5] the object does not. For either both must admit them or else neither, if indeed what is given by the account is the same as the object. Moreover, see if, while both of them admit of degrees, they yet do not both become greater together: e.g. suppose love to be the desire for intercourse; now he who is more intensely in love has not a [10] more intense desire for intercourse, so that both do not become intensified at once: they certainly should, however, had they been the same thing.
Moreover, suppose two things to be before you, see if the object applies in greater degree to the one to which the content of the account is less applicable. [15] Take, for instance, the definition of fire as the body that consists of the most rarefied particles. For flame is fire in greater degree than light is, but flame is less the body that consists of the most rarefied particles than is light; but both ought to be applicable in greater degree to the same thing, if they had been the same. Again, see if the one applies in equal degree to both the objects before you, while the other [20] does not apply to both alike, but more particularly to one of them.
Moreover, see if he renders the definition relative to two things taken separately: thus, the beautiful is what is pleasant to the eyes or to the ears; or the existent is what is capable of being acted upon or of acting. For then the same thing will be both beautiful and not beautiful, and likewise will be both existent and [25] non-existent. For pleasant to the ears will be the same as beautiful, so that not pleasant to the ears will be the same as not beautiful; for of identical things the opposites, too, are identical, and the opposite of beautiful is not beautiful, while of pleasant to the ears the opposite is not pleasant to the ears—clearly, then, not pleasant to the ears is the same thing as not beautiful. If, therefore, something is [30] pleasant to the eyes but not to the ears, it will be both beautiful and not beautiful. In like manner we shall prove also that the same thing is both existent and non-existent.
Moreover, of both genera and differentiae and all the other terms rendered in definitions you should frame accounts in lieu of the names, and then see if there is [35] any discrepancy between them.
8 · If the term defined is relative, either in itself or in respect of its genus, see whether the definition fails to mention that to which the term, either in itself or in [146b1] respect of its genus, is relative, e.g. if he has defined knowledge as an incontrovertible belief or wishing as painless appetition. For of everything relative the substance is relative to something else, seeing that the being of every relative term is identical with being in a certain relation to something. He ought, therefore, to have [5] said that knowledge is belief about a knowable and that wishing is appetition for a good. Likewise, if he has defined grammar as knowledge of letters—for in the definition there ought to be rendered either the thing to which the term itself is relative, or that to which its genus is relative. Or see if a relative term has been [10] described not in relation to its end, the end in anything being whatever is best or gives its purpose to the rest. Certainly it is what is best or final that should be stated, e.g. that desire is not for the pleasant but for pleasure; for this is our purpose in choosing what is pleasant.
Look and see also if that in relation to which he has rendered the term is a process or an activity; for nothing of that kind is an end, for the completion of the [15] activity or process is the end rather than the process or activity itself. Or perhaps this rule is not true in all cases; for almost everybody would rather be enjoying themselves than have ceased enjoying themselves, so that they would count the activity as the end rather than its completion.
[20] Again see in some cases if he has failed to distinguish the quantity or quality or place or other differentiae of an object; e.g. the quality and quantity of the honour the striving for which makes a man ambitious—for all men strive for honour, so that it is not enough to define the ambitious man as him who strives for honour, but the aforesaid differentiae must be added. Likewise, also, in defining the covetous man the quantity of money he aims at, or in the case of the incontinent man the quality of [25] the pleasures, should be stated. For it is not the man who gives way to any sort of pleasure whatever who is called incontinent, but only he who gives way to a certain kind of pleasure. Or again, people sometimes define night as a shadow on the earth, or an earthquake as a movement of the earth, or a cloud as condensation of the air, or a wind as a movement of the air; whereas they ought to specify as well quantity, [30] quality, place, and cause. Likewise, also, in other cases of the kind; for by omitting any differentiae whatever he fails to state the essence. One should always attack deficiency. For a movement of the earth does not constitute an earthquake, nor a movement of the air a wind, irrespective of its manner and the amount involved. [35]
Moreover, in the case of appetitions, and in any other cases where it applies, see if the word ‘apparent’ is left out: e.g. wishing is an appetition after the good, or desire is an appetition after the pleasant—instead of the apparently good or [147a1] pleasant. For often those who exhibit the appetition do not perceive what is good or pleasant, so that their aim need not be really good or pleasant, but only apparently so. They ought, therefore, to have rendered the definition accordingly. On the other hand, any one who maintains the existence of Ideas ought to be brought face to face [5] with his Ideas, even though he does render the term in question; for there can be no Idea of anything apparent and it seems that an Idea is always spoken of in relation to an Idea—thus desire itself is for the pleasant itself, and wishing itself is for the good itself; they therefore cannot be for an apparently good or an apparently pleasant; for the existence of the apparently good (or pleasant) itself would be an [10] absurdity.
9 · Moreover, if the definition is of the state of anything, look at what is in the state, while if it is of what is in the state, look at the state; and likewise in other cases of the kind. Thus if the pleasant is essentially beneficial, then, too, the man who is pleased is benefited. Speaking generally, in definitions of this sort it happens [15] that what the definer in a sense defines is more than one thing; for in defining knowledge, a man in a sense defines ignorance as well, and likewise also what has knowledge and what lacks it, and what it is to know and to be ignorant. For if the first is made clear, the others become in a certain sense clear as well. We have, then, [20] to be on our guard in all such cases against discrepancy, using the elementary principles drawn from consideration of contraries and of co-ordinates.
Moreover, in the case of relative terms, see if the species is rendered as relative to a species of that to which the genus is rendered as relative, e.g. supposing belief to be relative to the object of belief, see whether a particular belief is made relative to [25] some particular object of belief; and, if a multiple is relative to a fraction, see whether a particular multiple is made relative to a particular fraction. For if it is not so rendered, clearly a mistake has been made.
See, also, if the opposite of the term has the opposite account, whether (e.g.) [30] the account of half is the opposite of that of double; for if double is that which exceeds another by an equal amount to that other, half is that which is exceeded by an amount equal to itself. In the same way, too, with contraries. For to the contrary term will apply the account that is contrary in some one of the ways in which contraries are conjoined. Thus (e.g.) if useful is productive of good, injurious is productive of evil or destructive of good—for one or the ot
her of these is bound to be [147b1] contrary to the term originally used. Suppose then, neither of these things to be the contrary of the term originally used, then clearly neither of those rendered later will be an account of the contrary; and therefore the account originally rendered has not [5] been rightly rendered either. Seeing, moreover, that of contraries, the one is sometimes named by the privation of the other, as (e.g.) inequality seems to be the privation of equality (for things that are not equal are called unequal), it is therefore clear that the contrary named by the privation must of necessity be defined through the other; whereas the other cannot then be defined through the one named by the privation; for else we should find that each was being made known [10] by the other. We must in the case of contrary terms keep an eye on this mistake, e.g. supposing any one were to define equality as the contrary of inequality; for then he is defining it through the one named by the privation of it. Moreover, a man who so defines is bound to use in his definition the very term he is defining; and this becomes clear, if for the name we substitute its account. For to say ‘inequality’ is the [15] same as to say ‘privation of equality’. Therefore equality will be the contrary of the privation of equality, so that he will have used the very term to be defined. Suppose, however, that neither of the contraries is named by the privation, but yet the account of it is rendered in a manner like the above, e.g. suppose good to be defined as the contrary of evil, then it is clear that evil will be the contrary of good (for the accounts of things that are contrary in this way must be rendered in a like manner), [20] so that again he uses the very term being defined—for good is inherent in the account of evil. If, then, good is the contrary of evil, and evil is nothing other than the contrary of good, then good will be the contrary of the contrary of good. Clearly, [25] then, he has used the very term to be defined.
Moreover, see if in rendering a term named by the privation, he has failed to render the term of which it is the privation, e.g. the state, or contrary, or whatever it may be whose privation it is; also if he has omitted to add that in which the privation is naturally formed—either without qualification or else that in which it is naturally [30] formed primarily: e.g. whether in defining ignorance as a privation he has failed to say that it is the privation of knowledge; or has failed to add in what it is naturally formed, or, though he has added this, has failed to render the thing in which it is primarily formed, placing it (e.g.) in man or in the soul, and not in the reasoning faculty; for if in any of these respects he fails, he has made a mistake. Likewise, also, if he has failed to say that blindness is the privation of sight in an eye; for a proper [148a1] rendering of what it is must state both of what it is the privation and what it is that is deprived.
Examine further whether he has defined as a privation something not named by a privation—a mistake of this sort would seem to be incurred in the case of ignorance by any one who is not using it as a merely negative term. For what seems [5] to be ignorant is not that which has no knowledge, but rather that which has been deceived (for this reason we do not talk of inanimate things or of children as being ignorant). Ignorance, then, is not named by the privation of knowledge.
10 · Moreover, see whether the like inflexions in the account apply to the [10] like inflexions of the word; e.g. if beneficial is productive of health, is beneficially productively of health and a benefactor a producer of health?
Look too and see whether the definition given will apply to the Idea as well. For in some cases it will not do so; e.g. in the Platonic definition where he adds the word [15] ‘mortal’ in his definitions of living creatures; for the Idea (e.g. man itself) is not mortal, so that the account will not fit the Idea. In general, wherever the words ‘capable of acting on’ or ‘capable of being acted upon’ are added, the definition and the Idea are bound to be discrepant; for those who assert the existence of Ideas hold [20] that they are incapable of being acted upon, or of motion. In dealing with these people arguments of this kind are useful.
Further, see if he has rendered a single common account of terms that are used homonymously. For things whose account corresponding to their name is one and the same, are synonymous; if, then, the definition applies in a like manner to the [25] whole range of the homonym, it does not define any one of the objects described by the term. This is what happens to Dionysius’ definition of life when stated as a movement of a creature sustained by nutriment, congenitally present with it; for this is found in plants as much as in animals, whereas life seems to be not one kind of thing only, but one thing in animals and another in plants. It is possible to hold the [30] view that life is synonymous and of one kind only, and therefore to render the definition in this way on purpose; or it may quite well happen that a man may see the homonymy and wish to render the definition of the one sense only, and yet fail to see that he has rendered an account common to both instead of proper to one. In [35] either case, whichever course he pursues, he is equally at fault. Since homonymies sometimes pass unobserved, it is best in questioning to treat them as though they were synonymous (for the definition of the one will not apply to the other, so that [148b1] the answerer will seem not to have defined it correctly—for it should apply to the whole range of the synonym, whereas in answering you should yourself distinguish between them). Further, as some answerers call homonymous what is really synonymous, whenever the given account fails to apply to the whole range, and, vice versa, call synonymous what is really homonymous if it applies to both, one should [5] secure a preliminary agreement on such points, or else prove beforehand that so-and-so is homonymous or synonymous, as the case may be; for people are more ready to agree when they do not foresee what the consequence will be. If, however, no agreement has been made, and the man asserts that what is really synonymous is [10] homonymous because the account he has given will not apply to the second sense as well, see if the account of this second sense applies to the others; for if so, this must clearly be synonymous with those others. Otherwise, there will be more than one [15] definition of the others; for there are applicable to them two accounts corresponding to their names, viz. the one previously rendered and also the later one. Again, if anyone were to define a term used in several ways, and, finding that his account does not apply to them all, were to contend not that the term is homonymous, but that the name does not apply to all of them, just because his account will not do so [20] either, then one may retort to such a man that though in some things one must not speak with the vulgar, yet in a question of terminology one is bound to employ the received and traditional usage and not to upset matters of that sort.
11 · Suppose now that a definition has been rendered of some complex, take [25] away the account of one of the elements in the complex, and see if the rest of the account defines the rest of it: if not, it is clear that neither does the whole account define the whole complex. Suppose, e.g., that some one has defined a finite straight line as the limit of a finite plane, such that its centre is in a line with its extremes; if now the account of a finite line is the limit of a finite plane, the rest (viz. ‘such that [30] its centre is in a line with its extremes’) ought to be an account of straight. But an infinite straight line has neither centre nor extremes and yet is straight, so that the remainder is not an account of the remainder.
Moreover, if the term defined is a compound, see if the account given has as many members as the term defined. An account is said to have as many members as [35] the term defined when the number of the elements compounded is the same as the number of names and verbs in the account. For in such cases, there is bound to be an exchange of word for word, in the case of some if not of all, seeing that there are no [149a1] more words used now than formerly; whereas in a definition words ought to be rendered by accounts, if possible in every case, or if not, in the majority. For at that rate, simple objects too could be defined by merely calling them by a different name, e.g. cloak instead of doublet.
[5] The mistake is even worse, if in addition a less intelligible word is substitut
ed, e.g. pellucid mortal for white man; for it is no definition, and is less clear when put in that form.
Look and see also whether, in the exchange of words, the sense fails still to be the same. Take, for instance, the explanation of speculative knowledge as speculative [10] belief; for belief is not the same as knowledge—as it certainly ought to be if the whole is to be the same too; for though the word ‘speculative’ is common to both accounts, yet the remainder is different.
Moreover, see if in replacing one of the names by something else he has [15] exchanged the genus and not the differentia, as in the example just given; for speculative is less intelligible than knowledge; for the one is the genus and the other the differentia, and the genus is always the most familiar of all; so that it is not this, but the differentia, that ought to have been changed, seeing that it is the less [20] intelligible. (It might be held that this criticism is ridiculous because there is no reason why the most familiar name should not describe the differentia, and not the genus; in which case, clearly, the word to be altered should be that denoting the genus and not the differentia.) If, however, a man is substituting for a word not a word but an account, clearly it is of the differentia rather than of the genus that a [25] definition should be rendered, seeing that the object of rendering the definition is to make the subject familiar; for the differentia is less familiar than the genus.