30 THE PRINCIPLES OF SCIENCE. [chap. 



separate sound. In the case of substantial terms, certain 

 qualities may be present equally in each minutest part as 

 in the whole. The chemical nature of the largest mass of 

 pure carbonate of lime is the same as the nature of the 

 smallest particle. In the case of abstract terras, again, we 

 cannot draw a distinction between whole and part ; what 

 13 true of redness in any case is always true of redness, so 

 far as it is merely red. 



Synthesis of Terms. 



We continually combine simple terms together so as to 

 form new terms of more complex meaning. Thus, to 

 increase the intension of meaning of a term we write it 

 with an adjective or a phrase of adjectival nature. By 

 joining "brittle" to "metal," we obtain a combined term, 

 "brittle metal," wliich denotes a certain portion of the 

 metals, namely, such as are selected on account of pos- 

 sessing the quality of hrittleness. As we have already 

 seen, " brittle metal " possesses less extension and greater 

 intension than metal. Nouns, prepositional phrases, parti- 

 cipial phrases and subordinate propositions may also be 

 added to terms so as to increase their intension and 

 decrease their extension. 



In our symbolic language we need some mode of indi- 

 cating this junction of terms, and the most convenient 

 device will be the juxtaposition of the letter-terms. Thus 

 if A mean brittle, and B mean metal, then AB will mean, 

 brittle metal. Nor need there be any limit to the number 

 of letters thus joined together, or the complexity of the 

 notions which they may represent. 

 Thus if we take the letters 



P = metal, 



Q = white, 



K = monovalent, 



S = of specific gravity I0"5, 



T = melting above looo" C, 



V = good conductor of heat and electricity, 

 then we can form a combined term PQRSTV, which will 

 denote "a white monovalent metal, of specific gravity 105, 

 melting above 1000° C, and a good conductor of heat and 

 electricity." 



