CLASSIFICATION AND THE PREDICABLES, 89 



marked out from that genus by an assignable differentia, the najne of 

 the species must be connotative, and must connote the differentia; 

 but the connotation may be special, not involved in the signification of 

 the term as ordinarily used, but given to it when employed as a term of 

 art or science. The word Man, in common use, connotes rationality 

 and a certain form, but does not connote the number or character of 

 the teeth ; in the Linna?an system it connotes the number of incisor 

 and canine teeth, but does not connote rationality nor any ])articular 

 form. The word man has, therefore, two diftbrent meanings ; al- 

 though not commonly considered as ambiguous, because it happens in 

 both cases to denote the same individual objects. But a case is con- 

 ceivable in which the ambiguity would become evident : we have only 

 to imagine that some new kind of animal were discovered, having 

 Linna^us's three characteristics of humanity, but not rational, or not 

 of the human form. In ordinary parlance these animals would not be 

 called men ; but in natural history, they must still be called so by 

 those, if any there be, who adhere to the Linngean classification ; and 

 the question would arise, whether the word should continue to be used 

 in two senses, or the classification be given up, and the technical 

 sense of the term be abandoned along with it. 



Words not otherwise connotative may, in the mode just adverted to, 

 acquire a special or technical connotation. Thus the word whiteness, 

 as we have so often remarked, connotes nothing, it merely denotes the 

 attribute coiTesponding to a certain sensation ; but if we are making 

 a classification of colors, and desire to justify, or even merely to point 

 out, the particular place assigned to whiteness in our aiTangement, we 

 may define it, " the color produced by the mixture of all the simple 

 rays;" and this fact, though by no means implied in the meaning of 

 the word whiteness as ordinarily used, but only known by subsequent 

 scientific investigation, is part of its meaning in the particular essay or 

 treatise, and becomes the differentia of the species.* 



The differentia, tlierefore, of a species, may be defined to be, that 

 part of the connotation of the specific name, whether ordintuy, or 

 special and technical, which distinguishes the species in question fiom 

 all other species of the genus to which on the pai'ticular occasion we 

 are referring it. 



§ 7. Ha\'ing disposed of Genus, Species, and Differentia, we shall 

 not find much difficulty in attaining a clear conception of the distinction 

 between the other two predicables. 



In the Aristotelian phraseology. Genus and Differentia are of the, 

 essence of the subject ; by which, as we have seen, is really meant that 

 the properties signified by the genus and those signified by the differ- 

 entia, form part of the connotation of the name denoting the species. 

 Proprium and Accidens, on the other hand, form no part of the essence, 

 but are jiredicated of the species only accidental hi. l^oth va'e Acci- 

 dents in the wider sense, in which the accidents of a thing are opposed 

 to its essence ; although, in the doctrine of the Predicables, Accidena 

 is used for one sort of accident only, Proprium being another sort. 



* If we allow a differentia to what is not really a species. For the distinction of Kinds, 

 in the sense explained by us, not being in any way applicable to attributes, it of course fol- 

 lows, that although attributes may be put into classes, those classes can be admitted to be 

 genera or species only by courtesy. 



M 



