2 INTRODUCTION'. 



§ 2. Lo,gic has often been called the Art of Reasoning. A writer* 

 who has done more than any other living person to restore this study 

 to the rank from which it had fallen in the estimation of the cultivated 

 classes in our o\vn country, has adopted the above definition wth an 

 amendment; he has defined logic to be the Science, as well as the Art, 

 of reasoning ; meaning, by the fonner term, the analysis of the mental 

 process which takes place whenever we reason, and by the latter, the 

 rules, grounded upon that analysis, for conducting the process correctly. 

 There can be no doubt as to the propriety of the emendation. A right 

 understanding of the mental process itself, of the conditions it depends 

 upon, and the steps of which it consists, is the only basis on which a 

 system of rules, fitted for the direction of the process, can possibly be 

 founded. Art necessarily presupposes knowledge ; art, in any but its 

 infant. state, presupposes scientific knowledge; and if every art does 

 not bear the name of the science upon which it rests, it is only because 

 several sciences are often necessary to form the groundwork of a single 

 art. Such is the complication of human affairs, that to enable one thing 

 to be done, it is often requisite to hioio the nature and properties of 

 many things. 



Logic, then, comprises the science of reasoning, as well as an art, 

 founded on that science. But the word Reasoning, again, like most 

 other scientific terms in popular use, abounds in ambiguities. In one 

 of its acceptations, it means syllogizing; or the mode of inference 

 which may be called (vnth. sufficient accuracy for the present pui-pose) 

 concluding fi'om generals to particulars. In another of its senses, to 

 reason, is simply to infer any assertion, from assertions already admitted : 

 and in this sense, induction is as much entitled to be called reasoning 

 as the demonstrations of geometry. 



Writers on logic have generally preferred the former acceptation of 

 the teiTn ; the latter, and more extensive signification, is that in which 

 I mean to use it. I do this by ^Hrtue of the right I claim for eveiy 

 author, to give \vhatever prorisional definition he pleases of his ovra 

 subject. But sufficient reasons will, I believe, uiifold themselves as 

 we advance, why this should be not only the prorisional but the final 

 definition. It involves, at all events, no arbitrary change in the mean- 

 ing of the word; for, with the general usage of the English language, 

 the wider signification, I believe, accords better than the more re- 

 stricted one. 



§ 3. But reasoning, even in the widest sense of which the word is 

 susceptible, does not seem to include all that is included, either in the 

 best,. or even in the most cuiTent, conception of the scope and province 

 of our science. The employment of the word Logic to denote the 

 theory of ai-gumentaiion, is derived from the Aristotelion, or, as they 

 are commonly termed, the scholastic logicians. Yet even with them, 

 in their systerpatic treatises, argumentation was the subject only of the 

 third part : the two former treated of terms, and of propositions ; under 

 one or other of which heads were, moreover, included, Definition and 

 Division. Professedly, indeed, these prerious topics were introduced 

 only on account of their connexion with reasoning, and as a prepara- 

 tion for the doctrine and rules of syllogism. Yet they were treated 

 with greater mnuteness, and dwelt upon at greater length, than was 



* Archbishop Whately. 



