TERMS. 35 



from each other, either by their various shapes and sizes, 

 or, in the absence of such marks, by occupying simul- 

 taneously different parts of space. In substance they are 

 one ; as regards the properties of space they are many. 

 We need not further pursue this distinction between 

 unity and plurality until we come to consider the prin- 

 ciples of number in a subsequent chapter. 



Collective Terms. 



We must clearly distinguish between the collective and 

 the general meaning of terms. The same name may be 

 used to denote the whole body of existing objects of a 

 certain kind, or any one of those objects taken separately. 

 1 Man ' may mean the aggregate of existing men, which we 

 sometimes describe as mankind ; it is also the general 

 name applying to any man. The vegetable kingdom is 

 the name of the whole aggregate of plants, but * plant ' 

 itself is a general name applying to any one or other 

 plant. Every material object may be conceived as divi- 

 sible into parts, and is therefore collective as regards 

 those parts. The animal body is made up of cells and 

 fibres, a crystal of molecules ; wherever physical division, 

 or as it has been called partition, is possible, there we 

 deal in reality with a collective whole. Thus the greater 

 number of general terms are at the same time collective 

 as regards each individual whole which they denote. 



It need hardly be pointed out that we must not infer 

 of a collective whole what we know of the parts, nor of 

 the parts what we know only of the whole. The relation 

 of whole and part is not one of identity, and does not 

 allow of substitution. There may nevertheless be qualities 

 or circumstances which are true alike of the whole and its 

 parts. Thus a number of organ pipes tuned in unison 

 produce an aggregate of sound which is of exactly the same 



D 2 



