INTRODUCTION. 



1. THERE is as gre#t divecmy ambug 4Uthors in 

 the modes which they have adopted of defining logic, 

 as in their treatment of the details of it. This is 

 what might naturally be expected on any subject on 

 which writers have availed themselves of the same 

 language, as a means of delivering different ideas. 

 Ethics and jurisprudence are liable to the remark 

 in common with logic. Almost every philosopher 

 having taken a different view of some of the par- 

 ticulars which these branches of knowledge are usually 

 understood to include; each has so framed his defi- 

 nition as to indicate beforehand his own peculiar 

 tenets, and sometimes to beg the question in their 

 favour. 



This diversity is not so much an evil to be com- 

 plained of, as an inevitable and in some degree a 

 proper result of the imperfect state of those sciences. 

 There cannot be agreement about the definition of a 

 thing, until there is agreement about the thing itself. 

 To define a thing, is to select from among the whole 

 of its properties those which shall be understood to 

 be designated and declared by its name; and the 

 properties must be very well known to us before we 

 can be competent to determine which of them are 

 fittest to be chosen for this purpose. Accordingly, in 

 the case of so complex an aggregation of particulars 

 as are comprehended in anything which can be called 

 a science, the definition we set out with is seldom 

 that which a more extensive knowledge of the subject 

 VOL. i. B 



