TBHXEE8 VL MAWTIK. ^5 



THE PREFACE. 



A PREFACE in common language is that which 

 is put first. Technically it is that which is necessar/ 

 to the explanation, of any science with clearness and 

 perspicuity. It has therefore become an established 

 custom ^vith authors, previously to the introduction 

 „of their subject, to appropriate the first chapter to 

 this purpose, calling it a Preface. Under this head 

 are comprehended three different articles; 1st, The 

 nature or description of science ; 2d, The end or use 

 of the science ; 3d, The subject of the science ; or 

 those of its essential parts that are to be investigated 

 or considered ; such as the human body in medi- 

 cine, words and sentences in grammar, and dejini' 

 Hon. and demonstration in logic. 



Accordingly let it be understood, that knowledge, 

 or images acquired by the mind, is of two kinds ; 

 -either the simple impression of an object, or the pro- 

 duction of an image by reflection, that is, by rela- 

 tion. The first is perception, the second intellec- 

 tion or judgment. 



Perception is either the idea of a single object, 

 juch as the idea of Zeid ; or of several objects, such 

 as the idea of Zeid and Omar. Or it may be the 

 idea of an object standing in a relalion that is im- 

 perfect ; for example, the slave of Zeid ; or in a 

 relation that is perfect, in which case it must not be 

 connected with a predicate, but without one, such 

 as tht ezreh, (i.e.) heat ihoii. It may also be in 

 construction with a predicate, provided that it imply 

 no conclusion ; as in the idea of conjecture and 

 doubt. 



