286 OPERATIONS SUBSIDIARY TO INDUCTION. 



facts observed; and a name for every common pro- 

 perty of any importance or interest, which we detect 

 by comparing those facts: including (as the concretes 

 corresponding to those abstract terms) names for the 

 classes which we artificially construct in virtue of those 

 properties, or as many of them, at least, as we have 

 frequent occasion to predicate anything of. 



But there is a sort of classes, for the recognition 

 of which no such elaborate process is necessary ; be- 

 cause each of them is marked out from all others not 

 by some one property, the detection of which may 

 depend upon a difficult act of abstraction, but by its 

 properties generally. I mean, the Kinds of things, in 

 the sense which, in this treatise, has been systemati- 

 cally attached to that term. By a Kind, it will be 

 remembered, we mean one of those classes which are 

 distinguished from all others not by one or a few 

 definite properties, but by an unknown multitude of 

 them; the combination of properties on which the 

 class is grounded, being a mere index to an indefinite 

 number of other distinctive attributes. The class 

 horse is a Kind, because the things which agree in 

 possessing the characters by which we recognise a 

 horse, agree in a great number of other properties 

 as we know, and, it cannot be doubted, in many more 

 than we know. Animal, again, is a Kind, because no 

 definition that could be given of the name animal 

 could either exhaust the properties common to all 

 animals, nor supply premisses from which the re- 

 mainder of those properties could be inferred. But a 

 combination of properties which does not give evidence 

 of the existence of any other independent peculiarities, 

 does not constitute a Kind. White horse, therefore, 

 is not a Kind; because horses which agree in white- 



