DIVISIONS OF CONCEPTS AND TERMS. 53 



or written of or alluded to by those who believed in their real, 

 physical existence, or by any others who ever discussed such ac 

 counts, form the extension or denotation of the term dragon ; all 

 the different fairies that ever have been or ever will be described 

 or referred to by writers of fairy-tales or others whether these 

 believe or not in the real existence of such entities form the 

 extension or denotation of the term fairy ; all the entities ever 

 referred to or yet to be referred to under the name of ghosts, and 

 to which the term would be understood to be accurately applied, 

 form the extension or denotation of the term ghost ; all the 

 objects to which the term &quot; highest mountain in Asia &quot; can be 

 accurately applied (obviously only one) form the extension or 

 denotation of that term ; all the figures or outlines of material 

 things, past, present, or future, to which the term &quot; circle &quot; may 

 be correctly applied, form the extension or denotation of the term 

 circle. 



These various examples have been purposely chosen from 

 different spheres or realms of the objects of our thought in order 

 to emphasize a first important fact in connection with extension 

 or denotation : that it must always be sought in its appropriate 

 realm or sphere. This may be and of course most frequently is 

 the sphere of material real things, existing in time and space, 

 as in the example of man ; or it may be a sphere which some 

 believe to be real though not material, and which other un 

 believers in its reality consider to be an unreal sphere created by 

 the belief of the former class, as in the examples of angel or 

 spirit ; or it may be a realm once believed by some to be real, 

 though now universally admitted to be only imaginary, and thus 

 created by that belief, as in the instance of the dragon ; or it 

 may be anyone of the purely fictitious worlds of romance, poetry, 

 heraldry, fairyland, created by the inventive imagination of man, 

 as in the example of fairy. It must, however, be a realm which 

 is not only present to, but also independent of, the individual 

 thinker s actual thought, and to which an appeal can be made to 

 verify his judgments about the things therein (cf. 80, 123). 



Furthermore, actual membership of a class belonging to any such realm 

 is something different from mere logically possible membership of that class. 

 In other words, those various spheres of objects are all distinct from the 

 sphere of the purely possible^ of that which is merely conceivable by any 

 individual thinker s mind ; they are actual spheres, not merely thinkable 

 spheres. The condition for actual membership of a class in one or other of 

 those spheres may be either visible, mateiial existence ; or real, though 



