82 



NAMES AND PROPOSITIONS. 



animal : Rational (or rationality, for 

 it is of no consequence here whether 

 we us« the concrete or the abstract 

 form) is generally assigned by logi- 

 cians as the Differentia ; and doubt- 

 less this attribute serves the purpose 

 of distinction : but it has also been 

 remarked of man, that he is a c(M)king 

 animal : the only animal that dresses 

 its food. This, therefore is another 

 of the attributes by which the spe- 

 cies man is distinguished from other 

 species of the same genus : would 

 this attribute serve equally well for 

 a differentia? The Aristotelians say 

 No; having laid it down that the 

 differentia must, like the genus and 

 species, be of the essence of the sub- 

 ject. 



And here we lose even that vestige 

 of a meaning grounded in the nature 

 of the things themselves, which may 

 be supposed to be attached to the 

 word essence when it is said that 

 genus and species must be of the 

 essence of the thing. There can be 

 no doubt that when the schoolmen 

 talked of the essences of things as 

 opposed to their accidents, they had 

 confusedly in view the distinction 

 between differences of kind, and the 

 differences which are not of kind ; 

 they meant to intimate that genera 

 and species must be Kinds. Their 

 notion of the essence of a thing was a 

 vague notion of a something which 

 makes it what it is, i.e. which makes 

 it the Kind of thing that it is — which 

 causes it to have all that variety of 

 properties which distinguish its Kind. 

 But when the matter came to be 

 looked at more closely, nobody could 

 discover what caused the thing to 

 have all those properties, nor even 

 that there was anything which caused 

 it to have them. Logicians, however, 

 not liking to admit this, and being 

 unable to detect what made the thing 

 to be what it was, satisfied themselves 

 with what made it to be what it was 

 called. Of the innumerable properties 

 known and unknown that are com- 

 mon to the class man, a portion only, 

 Mud of course a very small portion, 



are connoted by its name ; these few, 

 however, will naturally have been 

 thus distinguished from the rest either 

 for their greater obviousness, or for 

 greater supposed importance. These 

 properties, then, which were connoted 

 by the name, logicians seized upon, 

 and called them the essence of the 

 species ; and not stopping there, they 

 affirmed them, in the case of the 

 injima species, to be the essence of 

 the individual too ; for it was their 

 maxim, that the species contained the 

 " whole essence " of the thing. Meta- 

 physics, that fertile field of delusion 

 propagated by language, does not 

 afford a more signal instance of such 

 delusion. On this account it was that 

 rationality, being connoted by the 

 name man, was allowed to be a dif- 

 ferentia of the class ; but the peculi- 

 arity of cooking their food, not being 

 connoted, was relegated to the class 

 of accidental properties. 



The distinction, therefore, between 

 Differentia, Pioprium, and Accidens, 

 is not grounded in the nature of things, 

 but in the connotation of names ; and 

 we must .seek it there if we wish to 

 find what it is. 



From the fact that the genus in- 

 eludes the species, in other words, de- 

 notes more than the species, or is pre- 

 dicable of a greater number of indi- 

 viduals, it follows that the species 

 must connote more than the genus. 

 It must connote all the attributes 

 which the genus connotes, or there 

 would be nothing to prevent it from 

 denoting individuals not included in 

 the genus. And it must connote 

 something besides, otherwise it would 

 include the whole genus. Animal de- 

 notes all the individuals denoted by 

 man, and many more. Man, there- 

 fore, must connote all that animal 

 connotes, otherwise there might be 

 men who are not animals ; and it 

 must connote something more than 

 animal connotes, otherwise all animals 

 would be men. This surplus of con- 

 notation — this which the species con- 

 notes over and above the connotation of 

 thegenus — is the Differentia, or specific 



