14 CLASSES OF IDEAS. SECT. XV. 3; 



1. Irritative ideas are thofe, which are preceded 

 by irritation, which is excited by objects external 

 to the organs of fenfe : as the idea of that tree, 

 which either I attend to, or which Khun in walking 

 near it without attention. In the former cafe it is 

 termed perception, in the latter it is termed limply 

 an irritative idea. 



2. Senfitive ideas are thofe, which are preceded 

 by the fenfation of pleafure or pain ; as the ideas, 

 which conftitute our dreams or reveries, this is 

 called imagination. 



3. Voluntary ideas are thofe, which are preceded 

 by voluntary exertion, as when I repeat the alpha- 

 bet backwards : this is called recollection. 



4. Aflbciate ideas are thofe, which are preceded 

 by other ideas or mufcular motions, as when we 

 think over or repeat the alphabet by rote in its 

 lifual order ; or fing a tune we are accuftomed to 5 

 this is called fuggeftion. 



III. i. Perceptions fignify thofe ideas, which 

 are preceded by irritation and fucceeded by 

 the fenfation of pleafure or pain, for whatever 

 excites our attention interefts us ; that is, it 

 is accompanied with pleafure or pain ; however 

 flight may be the degree or quantity of either of 

 them. 



The word memory includes two clafTes of ideas, 

 either thofe which are preceded by voluntary ex- 

 ertion, or thofe which are fuggefted by their aflb- 

 ciations with other ideas. 



2. Reafoning is that operation of the fenforium, 

 by which we excite two or many tribes of ideas ; 

 and then re-excite the ideas, in which they differ, 

 or correfpond. If we determine this difference, it 

 is called judgment; if we in vain endeavour to de- 

 termine it, it is called doubting. 



IP 



