304 THE SCIENCE OF LOGIC 



senses is the simplest and commonest form of ambiguity in 

 language. It is due to vagueness of conception, resulting from 

 want of accurate definition. Any of three terms of a syllogism 

 may be ambiguous : most usually it is &quot; ambiguous middle &quot; we 

 meet: in which case the syllogism really contains four terms. 

 Many of the stock examples of this fallacy, found in handbooks 

 of logic, are trifling ; its most debased and trivial form being the 

 pun. But equivocation is really a fertile source of very serious 

 and elusive errors. In the course of any sustained argument, 

 after the manner of the sorites, it may easily lurk unsuspected, owing 

 to the almost imperceptible differences in the varying shades of 

 meaning which may attach to the same term in different con 

 texts. Language is not a perfect instrument of thought. It 

 needs but little reflection on the elasticity of meaning discern 

 ible in such terms as &quot; idea,&quot; &quot; cause,&quot; &quot; law,&quot; &quot; nature,&quot; 

 &quot;government,&quot; &quot;liberty,&quot; &quot;money,&quot; &quot;free-trade,&quot; &quot;socialism,&quot; 

 &quot; home rule,&quot; etc. to enable one to realize what an amount of 

 error may be traced to this fallacy as its source. The following 

 few examples will be sufficient for illustration : &quot; Finis rei est 

 illius perfectio ; mors est finis vitae ; ergo mors est perfectio 

 vitae &quot;. &quot; What is rare is dear ; a horse for a penny is rare ; there 

 fore a horse for a penny is dear.&quot; &quot;Criminal actions are punish 

 able by law ; prosecutions for theft are criminal actions ; therefore 

 prosecutions for theft are punishable by law.&quot; 



() The fallacy of the CONCEPT WITH INCOMPATIBLE ATTRI 

 BUTES arises from a vague, unreflecting, careless way of thinking, 

 which can be remedied only by the deliberate analysis demanded 

 by the process of logical definition. To speak, for instance, of an 

 &quot; indivisible portion of matter &quot; is just as self-contradictory as to 

 speak of a &quot; square circle &quot;; while an ultimate analysis of some 

 of our concepts is so difficult that philosophers have at all times 

 disagreed as to whether or not certain combinations of them 

 such, for instance, as &quot;infinite quantity&quot; are self-contradic 

 tory. 



(&amp;lt;:) COMPOSITIO and Divisio, or the fallacies of confounding 

 the sensus compositus with the sensus divisus. Composition is the 

 fallacy of combining what ought to be kept separate; division 

 is the converse fallacy, of separating what ought to be kept com 

 bined. Aristotle seems to have had in view here the unlawful 

 combination or separation merely of words or phrases. &quot; Three 

 and four are odd arid even ; three and four are seven ; therefore 



