DEFINITION. 109 



existence of a class of triangles having one of these attributes 

 only, though no such class could exist Should the definition 

 contain a separable accident in addition to the differentia, it will 

 unduly lessen the denotation which we desire to ascribe to the 

 class in question. To define &quot;labourer&quot; as &quot;one who performs 

 manual work for wages &quot; would exclude slaves and others who, 

 though they may not work for wages, are certainly labourers. 



On the other hand, should the definition give only part of the 

 connotation (by assigning a remote instead of *&& proximate genus ; 

 or by assigning the latter alone, without the differentia], it will 

 unduly enlarge the denotation of the class name by including 

 groups never meant to be included (50). This is, perhaps, the most 

 common of all the mistakes liable to be committed in forming 

 definitions. 



Rule II. The terms which give the genus and differentia 

 respectively, must, of course, be less complex, more simple, than the 

 name of the class to be defined, seeing that the connotation of each 

 separately is less than that of the latter. But the terms of a defini 

 tion are often by no means so familiar as the term under definition ; 

 provided, however, they convey, when understood, a more explicit 

 knowledge of the nature of the thing than the name under defini 

 tion does, the definition is a good one. Familiarity with the 

 application of a term is often unaccompanied by any definite 

 knowledge of its implication. Such statements as that a &quot;net&quot; 

 is &quot;a reticulated fabric, decussated at regular intervals, with 

 interstices and intersections,&quot; that &quot; the lion is the king of beasts,&quot; 

 that &quot; bread is the staff of life,&quot; that &quot; logic is the medicine of 

 the mind,&quot; violate the rule under consideration ; the first of them 

 violating the third rule also. 



Rule III. The violation of this rule against tautology is 

 called a circulus in definiendo, defining in a circle. The fault is 

 committed whenever the term to be defined, or any other term 

 synonymous with it, is introduced into the definition. It is 

 likewise committed when we define relative terms (42) by their 

 correlatives : it is the ground of the relation that must be given 

 in such cases. Thus, &quot; virtue &quot; is not properly defined as &quot; the 

 opposite of vice&quot;. 



This rule may easily be violated in English owing to the 

 numerous synonyms which the language has derived from Teu 

 tonic and Latin sources. Of course, such flagrant violations as 

 &quot; Truth Is veracity,&quot; or &quot; Veracity is truth,&quot; would not be seriously 



