3. A third locus is, where the definiend is a complex whole having reference to several distinct facts or phenomena, while the definition indicates only one of them. Thus, if grammar be defined — the knowing how to write from dictation, you will object that it is just as much — the knowing how to read. The definition is incomplete unless it includes both.285

4. A fourth locus is, where the definiend admits both of a better and a worse construction, and where the definition enunciates only the worse. You may impugn it, on the ground that every cognition and every power must be understood as tending to its best results.286

6. A fifth locus is, where the definiend is enunciated as ranking, not in the lowest and nearest species to which it belongs but, in some higher and more distinct genus. Here the real essence will not be declared, and the definition will thus be incomplete; unless indeed it includes, along with the highest genus, the superadded mention of all the differentiæ descending down to the lowest species. It will then be complete, because it will include, in circumlocutory phrase, all that would be declared by enunciating the specific name.287

6. Assuming the genus to be truly declared in the definition you will examine whether the differentiæ enunciated are differentiæ at all? whether they really belong to the definiend? what is it which they serve to contrast with and exclude, — since, if there be nothing such, they cannot be truly differentiæ? whether the differential term and its counter-differential apply to and cover the whole genus? whether, granting the differentia to be real, it be such, when taken along with the genus, as to constitute a true species, and whether its counter-differentia be such also? This is a locus furnishing many possibilities of impugning the definition.288

7. Perhaps the definition may enunciate a differentia which is merely negative; e.g., A line is length without breadth. If you are debating with a respondent who holds the (Platonic) doctrine of Ideas, and who considers each Idea or genus to be something numerically one, distinct from all its participants, you will find here a locus for attacking them.289 He asserts the existence of a Self-long or generical long, a Self-animal or generic animal, each numerically one. Now, upon this hypothesis, since of all long you may predicate either in the affirmative or the negative (i.e., either it is broad or it is not broad), so this alternative may be predicated of the Self-long or generical long; and thus the genus will coincide with, or fall under the definition of, one among its own species. Or, if this be denied, it will follow that the generic long must be both broad and not broad; which is a contradiction still more inadmissible. Accordingly, against one who holds the doctrine of Ideas, declaring the genus to be unum numero, the negative differentia will furnish grounds for attack; but not against any other respondent.290 For there are various cases in which the negative must be employed as a part of the differentia: e.g., in privative terms, blind is one whose nature it is to see but who does not see. And, even when the differentia enunciated is affirmative, it may have for its condivident member only a negative term, e.g., length having-breadth has for its condivident member only the negative, length not-having-breadth.291

8. Perhaps the definition may enunciate as a differentia what is really a subordinate species; or what is really the genus itself under another name; or what is not Quale, but Quid; or what belongs to the definiend as an accident only. Each of these is a locus for arguments against the definition.292

9. Perhaps also, in the definition given, the differentia or the species may be found predicable of the entire genus; or the genus may be found predicable of the differentia itself, and not of objects under it; or the species (sometimes even one of its sub-species) may be found predicable of the differentia; or perhaps the differentia may not be a prius as regards the species (which it ought to be, while it is a posterius as regards the genus). Arguments against the definition may be drawn from any one of these loci.293

10. Recollect that the same differentia cannot belong to two distinct genera neither of which comprehends the other, unless both are comprehended under some higher genus. Examine whether this is observed in the definition tendered to you.294

11. No genuine differentia can be derived either from the Category Ubi or from the Category Passio; for neither of them furnishes characteristics essential to the subject. All Passio when intensified to a certain degree destroys the essence of the subject and removes it from its own appropriate species; but the differentia is inseparable from its subject; accordingly, nothing by virtue of which the subject is called ἀλλοῖον can be a true differentia. If the definition sins against this rule, it will be open to question.295

12. If the subject be relative, its true differentia ought to be relative also; thus, science or cognition is a relatum, and accordingly its three differentiæ — theoretical, practical, constructive — are all relata also.296 The definition must conform to this; and it must also, in cases where the relative subject has more than one correlate, declare that correlate which is the ordinary and natural one, not any other which is rare and realized only on occasion.297 You must watch to see whether this condition is observed; and also whether the correlative enunciated in the definition is the one strictly proximate. Thus, if the definition given of prudence be, It is an excellence of man or an excellence of the soul, this will not be a good definition. It ought to be — an excellence of the rational department of the soul; for it is through and by reason of this department that both man and soul are denominated prudent.298

13. When the definiend is given as an affection or lasting condition of some subject, you must examine whether it really resides or can reside (as by nature it ought to do) in the subject to which it is referred in the definition. If it cannot, the definition is untenable; and this mistake is sometimes made, the producing conditions of a phenomenon being confounded with the phenomenon itself, or vice versâ.299 Thus, some persons have defined sleep — incapacity of sensible perception; doubt — equality of contrary reasonings; pain — breach of continuity violently made in parts of the organism which naturally grow together. Now sleep does not reside in perception, nor doubt in reasonings. Sleep is that which produces or occasions incapacity of sensible perception; doubt is a state of mind produced by equality of contrary reasonings.300 This will be a locus for arguing against the definition.

14. Another locus is, when the definiend has direct bearing and reference to something different from what is enunciated in the definition. Thus, if the respondent defines justice — a power tending to make equal distribution, you may remark hereupon, that the just man is he who is deliberately resolved to make equal distribution, not he who has the power to do so. If this definition were allowed, the justest man would be he who has the greatest power of so distributing.301

15. Again, the definition will be assailable, if the definiend admits graduation of More or Less, while that which is enunciated in the definition does not admit it, or vice versâ; also, if both of them admit graduation, but the variations of the two are not corresponding and concomitant. The defining phrase ought to be identical in signification with the term defined.302 If both of them agree in reference to some common correlate, but one is to this in the relation of more while the other is in the relation of less, the definition is faulty.303

16. Again, you will be able to object, if the definition enunciate references to two distinct correlates, severally or alternately: e.g., The beautiful is that which affords pleasure either through the eye or through the ear; Ens is that which is capable either of suffering or acting. You may show that, according to this definition, beautiful and not beautiful, or that Ens and Non-Ens, will coincide and be predicable of the same subjects.304

17. When the definition is tendered, you ought to examine and define its own terms, which, of course, profess to enunciate genus and differentia of the definiend.305 You will see whether the definitions of those defining terms are in any way inapplicable to the definiend.

18. If the definiend be a Relatum, the definition ought to enunciate its true correlate, or the true correlate of the genus to which it belongs. You must examine whether this is done, and whether the correlate enunciated be an ultimate end, as it ought to be (i.e. not merely a means towards something ulterior). If the correlate enunciated is a generation or a process, this will afford you an argument against the definition; for all generation or process is a means towards some ulterior end.306

19. The definition ought not to omit any of the differentiæ of the definiend; if any be omitted, the real essence is not declared. Here then is a defect in the definition, which it is your business always to assail on its defective side.307 Thus, if the definiend be a relatum corresponding, not to some correlate absolutely but, to some correlate specially quantified or qualified, the definition ought to enunciate such quantification or qualification; if it does not, it is open to attack.

20. Suppose that the definiend is one of the appetites, relative to an appetitum as correlate, a mode of the good or agreeable. You will take notice whether the definition given thereof enunciates the correlate as only an apparent mode of good: if it does not, you have a locus for attacking it. But if it does, and if the definer be one who believes in the Platonic Ideas, you may attack him by showing that his definition will not square with that doctrine. For the definition as so given will not suit for the ideal or generic appetite — the Self-appetite; which correlates with the ideal or generic good — the Self-good. In this no distinction is admissible of real and apparent: a Self-apparent-good is an absurdity.308

21. Again, suppose that the definiend is a habit or disposition. You will examine how far the definition fits as applied to the individual person who has the habit; and how far it fits when taken in comparison with subjects contrary or congeneric. Every such definition, if good, implies in a certain way the definition of the contrary: he who defines cognition furnishes by implication the definition of ignorance.309

22. Or suppose the definiend to be a generic relatum, and the definition to enunciate its generic correlate. You must call to mind the specific terms comprehended under these two generic terms, and observe whether they fit on to each other respectively. If they do not, the definition is faulty.310

23. You will farther examine whether the Opposite of the definition will serve as definition to the Opposite of the definiend, as the definition of half is opposite to the definition of double; thus, if double is that which exceeds equality, half is that which is exceeded by equality. The like is true of Contraries: if the profitable be that which is productive of good, the hurtful will be that which is productive of evil or destructive of good. If, on trying the contraries, you find that this will not hold, the definition originally given will be found unsatisfactory.311 In defining the privative contrary of any term, a man cannot avoid enunciating in the definition the term of which it is the privative: but he is not allowed to define the term itself by means of its privative. To define equality — that which is contrary to inequality, is improper. You will require him at once to define inequality; and his definition must be — the privation of equality. Substitute this definition of the term inequality, in place of that term itself, in the above-named definition of equality: and the last definition will then run as follows: Equality is that which is contrary to the privation of equality. Here the definiend is enunciated as a part of the definition of itself; a proof that the original definition — Equality is the contrary of inequality — is itself wrong.312

24. When the definiend is a Privative Term, the definition given ought to enunciate that which it is, and that of which it is the privation; also that subject in which it resides naturally and in the first instance. In defining ignorance, the definition must enunciate not privation only, but privation of knowledge; nor will this be sufficient unless it be added that the privation of knowledge is in the rational department of the soul (ἐν τῷ λογιστικῷ). Privation of knowledge in the soul or in the man, will not suffice; because neither of these subjects is that in which the attribute resides in the first instance: the rational department of the soul must be named by itself, as being the primary subject of the attribute. If the definition be wanting in any of these conditions, you will have an argument for impeaching it.313

25. A term that is privative in form may sometimes be used in the sense of mere negation, not in that of privation. If this term be defined generally by privation, the definition will not include the merely negative sense, and will therefore be impeachable. The only general explanation attainable is that by pure negation, which is common both to the negative and the privative. Thus, if the respondent defines ignorance — privation of knowledge, such privation can be predicated only of subjects whose nature it is to have knowledge or who might be expected to have it: such privation cannot be predicated of infants, or of inanimate objects like stones. To include these, ignorance must be explained as the mere negation or non-existence of knowledge; the definition thereof by privation is inadequate.314

26. If you are debating with one who holds the Platonic doctrine of Ideas, you will note whether any definition that he may give fits not only the definiend itself but also the Idea of the definiend. Thus, Plato in defining animal introduces mortality as a part of his definition;315 but mortality cannot be predicated of the Idea or generic animal — the Self-animal; therefore, you will have an argument against his definition. In like manner, if any active or passive attribute is brought into his definition, you will object that this cannot apply to the Ideas; which are avowedly impassive and unchangeable.316

27. Another locus for counter-argument is, where the definiend is Equivocal or Analogous, while one and the same definition is made to apply to all its distinct meanings. Such a definition, pretending to fit all, will in reality fit none; nothing but an univocal term can come under one and the same definition. It is wrong to attempt to define an equivocal term.317 When its equivocation is not obvious, the respondent will put it forward confidently as univocal; while you as assailant will expose the equivocation. Sometimes, indeed, a respondent may pretend that an univocal word is equivocal, or that an equivocal word is univocal, in the course of the debate. To obviate such misconception, you will do well to come to an agreement with him prior to the debate, or to determine by special antecedent reasonings what terms are univocal or equivocal; for at that early stage, when he does not foresee the consequence of your questions, he is more likely to concede what will facilitate your attack. In the absence of such preliminary agreement, if the respondent, when you have shown that his bad definition will not apply universally, resorts to the pretence that the definiend, though really univocal, is equivocal, you will press him with the true definition of the part not included under his definition, and you will show that this true definition suits also for the remaining parts of the definiend. You will thus confute him by showing that, upon his original hypothesis, it must follow that there are two distinct definitions for the same definiend — the bad one which he has given, and the true one which you have constrained him to admit.318 Perhaps, however, the term which he has undertaken to define may be really equivocal, and therefore indefinable; nevertheless, when you have shown the insufficiency of his definition, he may refuse to admit that the term is equivocal, but will deny a portion of its real meaning. You will then remind him that, as to the meaning of names, we must recognize tradition and custom without presuming to disturb it; but that, when we combine these names in our own discourse, we must beware of those equivocations which mislead the multitude.319

28. If the definiend, of which a definition is tendered to you, is a compound, you may subtract from this definition the definition of one of the parts of the definiend, and then examine whether the remainder will suit as a definition of the remaining part of the definiend. If the remainder should not suit, this will show that the entire definition tendered is not tenable. Thus, if the definiend be a finite straight line, and if the definition tendered be, It is the boundary of a finite plane, of which (boundary) the middle covers or stands in the way of the extremities; you may subtract from this definition the definition of a finite line, viz., the boundary of a plane surface having boundaries, and the remainder of the definition ought then to suit for the remainder of the definiend. Now the remainder of the definiend is — straight; and the remainder of the definition is — that of which the middle covers or stands in the way of the extremities. But these two will not suit; for a line may be straight, yet infinite, in which case it will have neither middle nor extremities. Accordingly, since the remainder of the definition will not suit for the remainder of the definiend, this will serve as an argument that the entire definition tendered is not a good one.320

If the definiend be a compound, and if the definition contain no greater number of words than the definiend, the definition must be faulty; it will be nothing better than a substitution of words. Still more faulty will it be, if it substitutes rare and strange words in place of others which are known and familiar; or if it introduces a new word which signifies something different from that which it replaces.321