OP NAMES AND PEOPOSITIONg. 



CHAPTER I. 



'OP THE NECESSITY OF COMMENCING 

 WITH AN ANALYSIS OF LANGUAGE. 



§ I. It is so much the established 

 practice of Avriters on logic to com- 

 mence their treatises by a few general 

 observations (in most cases, it is true, 

 rather meagre) on Terms and their 

 varieties, that it will, perhaps, scarcely 

 be required from me in merely follow- 

 ing the common usage, to be as parti- 

 cular in assigning my reasons, as it is 

 usually expected that those should be 

 who deviate from it. 



The practice, indeed, is recom- 

 mended by considerations far too 

 obvious to require a formal justifica- 

 tion. Logic is a portion of the Art 

 of Thinking : Language is evidently, 

 and by the admission of all philoso- 

 phers, one of the principal instruments 

 or helps of thought ; and any imper- 

 fection in the instrument, or in the 

 mode of employing it, is confessedly 

 liable, still more than in almost any 

 other art, to confuse and impede the 

 process, and destroy all ground of 

 confidence in the result. For a mind 

 not previously versed in the meaning 

 a,nd right use of the various kinds of 

 words, to attempt the study of methods 

 of philosophising, would be as if some 

 one should attempt to become an 

 astronomical observer, having never 

 learned to adjust the focal distance 

 of his optical instruments so as to see 

 distinctly. 



Since Reasoning, or Inference, the 

 J)rincipal subject of logic, is an opera- 



tion which usually takes place by 

 means of words, and in complicated 

 cases can take place in no other way ; 

 those who have not a thorough insight 

 into the signification and purposes of 

 words, will be under chances, amount- 

 ing almost to certainty, of reasoning 

 or inferring incorrectly. And logi- 

 cians have generally felt that unless, 

 in the very first stage, they removed 

 this source of error ; unless they taught 

 their pupil to put away the glasses 

 which distort the object, and to use 

 those which are adapted to his purpose 

 in such a manner as to assist, not per- 

 plex, his vision ; he would not be in 

 a condition to practise the remaining 

 part of their discipline with any pro- 

 spect of advantage. Therefore it is 

 that an inquiry into language, so far 

 as is needful to guard against the 

 errors to which it gives rise, has at all 

 times been deemed a necessary pre- 

 liminary to the study of logic. 



But there is another reason, of a 

 still more fundamental nature, why 

 the import of words should be the 

 earliest subject of the logician's con- 

 sideration : because without it he can- 

 not examine into the import of Pro- 

 positions. Now this is a subject which 

 stands on the very threshold of the 

 science of logic. 



The object of logic, as defined in 

 the Introductory Chapter, is to ascer- 

 tain how we come by that portion of 

 our knowledge (much the greatest 

 portion) which is not intuitive : and 

 by what criterion we can, in matters 

 not self-evident, distinguish between 



