80 GENERAL VIEW AND BASIS OF SCIENTIFIC RESEARCH. 



to which they are related by the idea of difference. ' Ab- 

 solute ' terms cannot be properly used in cases of degree. 

 A ' relative ' term represents an idea which cannot be 

 thought of alone, but only in relation to some other idea ; 

 thus the term ' heavy ' can only be thought of in relation 

 to ' less heavy ' or ' light ; ' that which is ' bright ' can only 

 be thought of in connection with that which is 'less 

 bright ' or ' dull.' Eelative terms are incommensurable, 

 and have often no real counterpart in nature. Correla- 

 tive terms are those belonging to the respective relative 

 ones. 



The chief division of terms for scientific purposes is 

 into general and singular. A ' general ' term is one which 

 may be used to denote any one of an indefinite number of 

 similar ideas or things ; as the term ' gas ' may be applied 

 either to hydrogen, nitrogen, oxygen, chlorine, &c., or to 

 any other substance possessing the general properties of a 

 gas. A 'singular' or 'individual' term is one which, so 

 long as it is employed only in exactly the same meaning, 

 can only represent a single idea or thing ; and, unlike a 

 general term, it has a different meaning in every different 

 case ; and again, if it is divided, the parts cannot be properly 

 called by the same name as the whole. General ideas and 

 terms represent qualities and properties, which have no 

 existence independent of the class of objects in which 

 they are found ; but singular ideas and terms represent 

 individual and separately existing objects. A general 

 term must not be confounded with a collective one. Whilst 

 a general term is the name of a number of objects, but of 

 each of them separately, a ' collective ' term is that of a 

 collection of objects combined together in one whole. 

 When we generalise, we form a collective term. Some 

 terms are both general and collective. 



A general term is, in logical phraseology, said to 



