88 NAMES AND PROPOBITIONS. 



be a Kind. But if we coxild do this, man would not be, as it was as- 

 sumed to be, the pi-oxiraate Kind. Therefore the properties of the 

 proximate Kind do comj^rehend those (whether known or unknown) 

 of all other Kinds to which the individual belongs ; which was the 

 point we undertook to prove. And hence, every other Kind which is 

 predicable of the individual, will be to the proximate Kind in the re- 

 lation of a genus, according to even the popular acceptation of the 

 terms genus and species ; that is, it wall be a larger class, including it 

 and more. 



We are now able to fix also the logical meaning of these terms. 

 Every class which is a real Kind, that is, which is distinguished fiom 

 all other classes by an indeterminate multitude of properties not deriv- 

 able from another, is eitlier a genus or a species. A Kind which is not 

 divisible into other Kinds, cannot be a genus, because it has no species 

 under it; but it is itself a species, both with reference to the indi- 

 viduals below and to the genera above (Species Praedicabilis and Species 

 Subjicibilis). But every Kind which admits of division into real Kinds 

 (as animal into quadruped, bird, &c., or quadiTiped into various species 

 of quadrupeds) is a genus to all below it, a species to all genera in 

 which it is itself included. And here we may close this part of the 

 discussion, and pass to the three remaining predicables. Differentia, 

 Proprium, and Accidens. 



§ 5. To b.egin with Differentia. This word is correlative with the 

 words genus and species, and as all agree, it signifies the attribute 

 which distinguishes a given species from every other species of the 

 same genus. This is so far clear: but which of the distinguishing 

 attributes does it signify 1 For we have seen that eveiT^ Kind (and a 

 species must be a Kind) is distinguished from other Kinds not by any 

 one attribute, but by an indefinite number. Man, for instance, is a 

 species of the genus animal ; Rational (or rationality, for it is of no 

 consequence whether we use the concrete or the abstract form) is gen- 

 erally assigned by logicians as the Differentia; and doubtless this 

 attribute serves the pxu-pose of distinction : but it has also been re- 

 marked of man, that he is a cooking animal; the only animal that 

 dresses its food. This, therefore, is another of the attributes by which 

 "the species man is distinguished from other species of the same genus; 

 would this attribute serve equally well for a differeutia ] The Aristo- 

 telians say No ; having laid it down that the differentia must, like the 

 genus and species, be of the essence of the subject. 



And here we lose even that vestige of a meaning gi'ounded in the 

 nature of the things themselves, which maybe 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 school- 

 men 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, ?'. 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 cam^ to be looked at more closely, nobody could discover what 

 caused the thing to have all those properties, nor even that there was 



