BOOK I. 



OF NAMES AND PROPOSITIONS. 



" La scolastique, qui produisit dans la logique, comme dans la morale, et dans une partie 

 de la mctaphysique, une subtilitc, une precision d'idees, dont I'habitude inconnue aux an- 

 ciens, a contribue plus qu'on nacroit au progrtis de la bonne philosoplrie."— Condorcet, 

 Vie de Turcot. 



CHAPTER I. 



OF THE NECESSITY OF COMMENCING WITH AN ANALYSIS OF LANGUAGE. 



§ 1. It is SO much the estabhshed practice of wi-iters on logic to 

 commence their treatises by a few general observations (in most cases, 

 it is true, rather meagre) on Terms and their varieties, that it will, per- 

 haps, scarcely be required from me, in merely following the common 

 usage, to be as particular in assigning my reasons, as it is usually ex- 

 pected that those should be who deviate from it. 



The practice, indeed, is recommended by considerations far too ob- 

 vious to require a formal justification. Logic is a portion of the Art 

 of Thinking : Language is evidently, and by the admission of all phi- 

 losophers, one of the principal instruments or helps of thought ; and 

 any imperfection in the instrument, or in the mode of employino- it, is 

 confessedly liable, still more than in almost any other art, to confuse 

 and impede the process, and desti'oy all gi-ound of confidence in the 

 result. For a mind not previously versed in the meaning and right use 

 of the various kinds of words, to attempt the study of methods of phi- 

 losophizing, would be as if some one should attempt to make himself 

 an astronomical observer, having never learned to adjust the focal dis- 

 tance of his optical instruments so as to see distinctly. 



Since Reasoning, or Inference, the principal subject of logic, is an 

 operation which usually takes place by means of words, and in all 

 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 

 imder almost a necessity of reasoning or infen-ing incon-ectly. And 

 logicians have generally felt that unless, in the very first stage, they 

 removed this fertile 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 perplex, 

 his vision ; he would not be in a condition to practise the remaining 

 part of their discipline with any prospect 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 neces- 

 sary preliminary to the science of logic. 



But there is another reason, of a still more fundamental nature, why 



