iv PREFACE. 



need of improvement) can only consist in performing, 

 more systematically and accurately, operations with 

 which, at least in their elementary form, the human 

 intellect in some one or other of its employments is 

 already familiar. 



In the portion of the work which treats of Ratio- 

 cination, the author has not deemed it necessary to 

 enter into technical details which may be obtained in 

 so perfect a shape from the existing treatises on what 

 is termed the Logic of the Schools. In the contempt 

 entertained by many modern philosophers for the 

 syllogistic art, it will be seen that he by no means 

 participates ; although the scientific theory on which 

 its defence is usually rested appears to him erro- 

 neous : and the view which he has suggested of the 

 nature and functions of the Syllogism may, perhaps, 

 afford the means of conciliating the principles of the 

 Art with as much as is well-grounded in the doctrines 

 and objections of its assailants. 



The same abstinence from details could not be 

 observed in the First Book, on Names and Proposi- 

 tions ; because many useful principles and distinctions 

 which were contained in the old Logic, have been 

 gradually omitted from the writings of its later 

 teachers; and it appeared desirable both to revive 

 these, and to reform and rationalize the philosophical 

 foundation on which they stood. The earlier chapters 

 of this preliminary Book will consequently appear, to 

 some readers, needlessly elementary and scholastic. 

 But those who know in what darkness the nature of 

 our knowledge, and of the processes by which it is 



