94 THE SCIENCE OF LOGIC. 



of properties necessary for identification rather than the maximum 

 which it is possible to include &quot;. l Hence the analysis in question 

 should be confined to the connotation of the name of the object. 



Secondly, it has never been regarded as necessary to analyse 

 the connotation into its simplest \ ultimate factors , and to set forth 

 a complete list of these as the definition of the term. Such a 

 process would be needlessly long and cumbrous. And as a 

 matter of fact it has been traditionally regarded as sufficient for 

 the purpose of definition to go back one step in the analysis of 

 the connotation, by setting forth explicitly the genus proximum 

 and the differentia specified of the object to be defined. 



In order, therefore, to define any object of thought, we must 

 find out and indicate its proximate genus the next highest class 

 into which it naturally falls 2 (47) and the attribute or group of 

 attributes which distinguishes it from other cognate species of the 

 same genus. Care must be taken that the genus selected be the 

 next highest ; otherwise the definition will prove faulty by omitting 

 portion of the connotation, and applying to other things besides 

 the thing defined. Thus, were we to define a square as a &quot;paral 

 lelogram having its adjacent sides equal,&quot; we should be omitting 

 the attribute &quot; right-angled,&quot; and our definition would include 

 not merely squares but lozenges. 



The reason for limiting the analysis required in definition to 

 one step, is sufficiently simple. The aim of definition from the 

 point of view of logic being to secure distinctness in our ideas, 

 it ought to avoid lengthy analysis which would lead rather to 

 confusion ; and we ought to assume that, if our concept of the 

 thing to be defined is not already distinct, at all events the simpler 



1 KEYNES, Formal Logic, p. 55. This minimum, however, must be not merely 

 any minimum that will serve to identify the class, but that particular minimum 

 which contains the fundamental factors included in the connotation (47). For 

 identification of objects is not the primary aim of definition : it aims rather at 

 giving us information about their nature (53). This, however, we must bear in 

 mind, is an ideal that is not always attainable. In the classificatory sciences of 

 botany and zoology the natural kinds of things are so complex that it is extremely 

 difficult to say which attributes are of &quot; fundamental importance &quot; (66), and so we 

 have often to follow the &quot; identification &quot; ideal in our definitions : &quot; our differentiae 

 are intended as much to be diagnostic i.e. features by which a species may be 

 identified as to declare the essential nature of the species &quot;. JOSEPH, op. cit., 

 p. 116. 



2 One and the same class may fall into different proximate genera according to 

 the point of view from which we reach a knowledge of it and classify it. In such 

 cases we may define the class if it have the same name in more than one scheme of 

 classification in different ways : what is its differentia in one case being a property 

 in the others (51). Such cases are, however, rare. 



