so far as we are aware, they might be absent without making the name inapplicable and the species a different species-are yet never in fact known to be absent. A concise mode of expressing the same meaning is, that inseparable accidents are properties which are universal to the species, but not necessary to it. Thus, blackness is an attribute of a crow, and, as far we know, an universal one. But if we were to discover a race of white birds, in other respects resembling crows, we should not say, These are not crows; we should say, These are white crows. Crow, therefore, does not connote blackness; nor, from any of the attributes which it does connote, whether as a word in popular use or as a term of art, could blackness be inferred. Not only, therefore, can we conceive a white crow, but we know of no reason why such an animal should not exist. Since, however, none but black crows are known to exist, blackness, in the present state of our knowledge, ranks as an accident, but an inseparable accident, of the species crow. Separable Accidents are those which are found, in point of fact, to be sometimes absent from the species; which are not only not necessary, but not even universal. They are such as do not belong to every individual of the species, but only to some individuals; or if to all, not at all times. Thus the colour of an European is one of the separable accidents of the species man, because it is not an attribute of all human creatures. Being born, is also (speaking in the logical sense) a separable accident of the species man, because, though an attribute of all human beings, it is so only at one particular time. A fortiori those attributes which are not constant even in the same individual, as, to be in one or in another place, to be hot or cold, sitting or walking, must be ranked as separable accidents. CHAPTER VIII. OF DEFINITION. § 1. ONE necessary part of the theory of Names and of Propositions remains to be treated of in this place: the theory of Definitions. As being the most important of the class of propositions which we have characterised as purely verbal, they have already received some notice in the chapter preceding the last. But their fuller treatment was at that time postponed, because definition is so closely connected with classification, that, until the nature of the latter process is in some measure understood, the former cannot be discussed to much purpose. The simplest and most correct notion of a Definition is, a proposition declaratory of the meaning of a word; namely, either the meaning which it bears in common acceptation, or that which the speaker or writer, for the particular purposes of his discourse, intends to annex to it. The definition of a word being the proposition which enunciates its meaning, words which have no meaning are unsusceptible of definition. Proper names, therefore, cannot be defined. A proper name being a mere mark put upon an individual, and of which it is the characteristic property to be destitute of meaning, its meaning cannot of course be declared; though we may indicate by language, as we might indicate still more conveniently by pointing with the finger, upon what individual that particular mark has been, or is intended to be, put. It is no definition of "John Thomson to say he is "the son of General Thomson;" for the name John Thomson does not express this. Neither is it any definition of "John Thomson to say he is "the man now crossing the street." These propositions may serve to make known who is the particular man to whom the name belongs, but that may be done still more unambiguously by pointing to him, which, however, has not been esteemed one of the modes of defini- | subject. All propositions the truth tion. of which is implied in the name, all In the case of connotative names, those which we are made aware of by the meaning, as has been so often ob- merely hearing the name, are included served, is the connotation; and the in the definition, if complete, and may definition of a connotative name is be evolved from it without the aid of the proposition which declares its con- any other premises; whether the denotation. This might be done either finition expresses them in two or three directly or indirectly. The direct words, or in a larger number. It is, mode would be by a proposition in therefore, not without reason that this form: "Man (or whatsoever Condillac and other writers have the word may be) "is a name connot- affirmed a definition to be an analysis. ing such and such attributes," or "is To resolve any complex whole into a name which, when predicated of the elements of which it is comanything, signifies the possession of pounded, is the meaning of analysis; such and such attributes by that and this we do when we replace one thing." Or thus: Man is everything word which connotes a set of attriwhich possesses such and such attributes collectively, by two or more butes; Man is everything which pos- which connote the same attributes sesses corporeity, organisation, life, singly or in smaller groups. rationality, and certain peculiarities of external form. § 2. From this, however, the quesThis form of definition is the most tion naturally arises, in what manne precise and least equivocal of any; are we to define a name which conbut it is not brief enough, and is be- notes only a single attribute: for insides too technical for common dis- stance, "white," which connotes nocourse. The more usual mode of de- thing but whiteness; "rational,” claring the connotation of a name is which connotes nothing but the pos to predicate of it another name or session of reason. It might seem that names of known signification, which the meaning of such names could only connote the same aggregation of attri- be declared in two ways; by a synonybutes. This may be done either by mous term, if any such can be found; predicating of the name intended to or in the direct way already alluded be defined another connotative name to: "White is a name connoting the exactly synonymous, as, "Man is a attribute whiteness." Let us see, human being," which is not commonly however, whether the analysis of the accounted a definition at all; or by meaning of the name, that is, the predicating two or more connotative names, which make up among them the whole connotation of the name to be defined. In this last case, again, we may either compose our definition of as many connotative names as there are attributes, each attribute being connoted by one, as, Man is a corporeal, organised, animated, rational being, shaped so and so; or we may employ names which connote several of the attributes at once, as, Man is a rational animal, shaped so and so. The definition of a name, according to this view of it, is the sum total of all the essential propositions which can be framed with that name for their breaking down of that meaning into In regard to such names of attributes as are connotative, and express : attributes of those attributes, there is the cause and the effect, we obtain a definition of eloquence, viz. the power of influencing the feelings by speech or writing. 66 no difficulty like other connotative names, they are defined by declaring their connotation. Thus the word fault may be defined, "a quality productive of evil or inconvenience." Sometimes, again, the attribute to be defined is not one attribute, but an union of several: we have only, therefore, to put together the names of all the attributes taken separately, and we obtain the definition of the name which belongs to them all taken together; a definition which will correspond exactly to that of the corresponding concrete name. For, as we define a concrete name by enumerating the attributes which it connotes, and as the attributes connoted by a concrete name form the entire signification of the corresponding abstract name, the same enumeration will serve for the definition of both. Thus, if the definition of a human being be this, a being, corporeal, animated, rational, shaped so and so," the definition of humanity will be corporeity and animal life, combined with rationality, and with such and such a shape. When, on the other hand, the abstract name does not express a complication of attributes, but a single attribute, we must remember that every attribute is grounded on some fact or phenomenon, from which, and which alone, it derives its meaning. To that fact or phenomenon, called in a former chapter the foundation of the attribute, we must, therefore, have recourse for its definition. Now, the foundation of the attribute may be a phenomenon of any degree of complexity consisting of many different parts, either co-existent or in succession. To obtain a definition of the attribute, we must analyse the phenomenon into these parts. Eloquence, for example, is the name of one attribute only; but this attribute is grounded on external effects of a complicated nature, flowing from acts of the person to whom we ascribe the attribute; and by resolving this phenomenon of causation into its two parts, A name, therefore, whether concrete or abstract, admits of definition, provided we are able to analyse, that is, to distinguish into parts, the attribute or set of attributes which constitute the meaning both of the concrete name and of the corresponding abstract: if a set of attributes, by enumerating them; if a single attribute, by dissecting the fact or phenomenon (whether of perception or of internal consciousness) which is the foundation of the attribute. But, farther, even when the fact is one of our simple feelings or states of consciousness, and therefore unsusceptible of analysis, the names both of the object and of the attribute still admit of definition : or rather, would do so if all our simple feelings had names. Whiteness may be defined, the property or power of exciting the sensation of white. A white object may be defined, an object which excites the sensation of white. The only names which are unsusceptible of definition, because their meaning is unsusceptible of analysis, are the names of the simple feelings themselves. These are in the same condition as proper names. They are not indeed, like proper names, unmeaning; for the words sensation of white signify, that the sensation which I so denominate resembles other sensations which I remember to have had before, and to have called by that name. But as we have no words by which to recall those former sensations, except the very word which we seek to define, or some other which, being exactly synonymous with it, requires definition as much, words cannot unfold the signification of this class of names; and we are obliged to make a direct appeal to the personal experience of the individual whom we address. §3. Having stated what seems to be the true idea of a Definition, I proceed to examine some opinions of philosophers, and some popular con ceptions on the subject, which conflict more or less with that idea. by the inadequate definition as by an adequate one. Such definitions, however, are always liable to be overthrown by the discovery of new objects in nature. The only adequate definition of a name is, as already remarked, one Definitions of this kind are what which declares the facts, and the logicians have had in view when whole of the facts, which the name they laid down the rule that the involves in its signification. But with definition of a species should be per most persons the object of a definition genus et differentiam. Differentia bedoes not embrace so much; they looking seldom taken to mean the whole for nothing more, in a definition, than of the peculiarities constitutive of a guide to the correct use of the term the species, but some one of those -a protection against applying it in peculiarities only, a complete definia manner inconsistent with custom tion would be per genus et differentias, and convention. Anything, there- rather than differentiam. It would fore, is to them a sufficient definition include, with the name of the superior of a term which will serve as a cor- genus, not merely some attribute rect index to what the term denotes; which distinguishes the species inthough not embracing the whole, and tended to be defined from all other sometimes, perhaps, not even any species of the same genus, but all the part, of what it connotes. This gives attributes implied in the name of the rise to two sorts of imperfect or un- species, which the name of the supescientific definition; Essential but in- rior genus has not already implied. complete Definitions, and Accidental The assertion, however, that a definiDefinitions, or Descriptions. In the tion must of necessity consist of a former, a connotative name is defined genus and differentiæ, is not tenable. by a part only of its connotation; in It was early remarked by logicians, the latter, by something which forms that the summum genus in any classi no part of the connotation at all. fication, having no genus superior to itself, could not be defined in this manner. Yet we have seen that all names, except those of our elementary feelings, are susceptible of definition in the strictest sense; by setting forth in words the constituent parts of the fact or phenomenon, of which the connotation of every word is ultimately composed. An example of the first kind of imperfect definitions is the following: -Man is a rational animal. It is impossible to consider this as a complete definition of the word Man, since (as before remarked) if we adhered to it we should be obliged to call the Houyhnhnms men; but as there happen to be no Houyhnhnms, this imperfect definition is sufficient to mark out and distinguish from all other things the objects at present denoted by "man;" all the beings actually known to exist of whom the name is predicable. Though the word is defined by some only among the attributes which it connotes, not by all, it happens that all known objects which possess the enumerated attributes possess also those which are omitted; so that the field of predication which the word covers, and the employment of it which is conformable to usage, are as well indicated § 4. Although the first kind of imperfect definition, (which defines a connotative term by a part only of what it connotes, but a part sufficient to mark out correctly the boundaries of its denotation,) has been considered by the ancients, and by logicians in general, as a complete definition, it has always been deemed necessary that the attributes employed should really form part of the connotation; for the rule was that the definition must be drawn from the essence of the class; and this would not have been the case if it had been in any degree made up of attributes not connoted by the name. The second kind of imperfect definition, therefore, in which the name of a class is defined by any of its accidents, that is, by attributes which are not included in its connotation,-has been rejected from the rank of genuine Definition by all logicians, and has been termed Description. This kind of imperfect definition, however, takes its rise from the same cause as the other, namely, the willingness to accept as a definition anything which, whether it expounds the meaning of the name or not, enables us to discriminate the things denoted by the name from all other things, and consequently to employ the term in predication without deviating from established usage. This purpose is duly answered by stating any (no matter what) of the attributes which are common to the whole of the class, and peculiar to it; or any combination of attributes which happens to be peculiar to it, though separately each of those attributes may be common to it with some other things. It is only necessary that the definition (or description) thus formed should be convertible with the name which it professes to define; that is, should be exactly co-extensive with it, being predicable of everything of which it is predicable, and of nothing of which it is not predicable; though the attributes specified may have no connection with those which mankind had in view when they formed or recognised the class, and gave it a name. The following are correct definitions of Man, according to this test: Man is a mammiferous animal, having (by nature) two hands (for the human species answers to this description, and no other animal does): Man is an animal who cooks his food: Man is a featherless biped. has in view. As was seen in the preceding chapter, it may, for the ends of a particular art or science, or for the more convenient statement of an author's particular doctrines, be advisable to give to some general name, without altering its denotation, a special connotation, different from its ordinary one. When this is done, a definition of the name by means of the attributes which make up the special connotation, though in general a mere accidental definition or description, becomes on the particular occasion and for the particular purpose a complete and genuine defini tion. This actually occurs with respect to one of the preceding examples, "Man is a mammiferous animal having two hands," which is the scientific definition of man, considered as one of the species in Cuvier's distribution of the animal kingdom. In cases of this sort, though the definition is still a declaration of the meaning which in the particular instance the name is appointed to convey, it cannot be said that to state the meaning of the word is the purpose of the definition. The purpose is not to expound a name, but a classification. The special meaning which Cuvier assigned to the word Man, (quite foreign to its ordinary meaning, though involving no change in the denotation of the word,) was incidental to a plan of arranging animals into classes on a certain principle, that is, according to a certain set of distinctions. And since the definition of Man according to the ordinary connotation of the word, though it would have answered every other purpose of a definition, would not have pointed out the place which the species ought to occupy in that particular classification, he gave the word a special connotation, that he might be able to define it by the kind of attributes on which, for reasons of scienWhat would otherwise be a mere tific convenience, he had resolved to description may be raised to the rank found his division of animated nature. of a real definition by the peculiar Scientific definitions, whether they purpose which the speaker or writer | are definitions of scientific terms, or |