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CHAP. I. 



SECT. I. 



Of the Ideas of Sensation. 



O< 



senses are the only source of those ideas* 

 upon which all our knowledge is founded. Without 

 ideas of some sort or other we could have no know- 

 ledge, and without our senses we could have no ideas. 

 But these being once transmitted to the memory, the 

 soul, which till then was still an unactive being, sup- 

 plied with materials to work upon, begins to exert 

 fcer operations. 



Before we speak of the properties of ideas of sen. 

 sation, it is proper to observe three things: 1. That 

 it is not necessary to decide, whether sensitive percep- 

 tion be performed, by an impression of the object 

 upon the sense, or by an operation of the sense upon 

 the object. It is certain, that either way of sensitive 

 perception necessarily requires the presence of the 

 object, and an immediate action, either of the organ 

 upon this, or of this upon the organ : consequent 

 upon which is a sort of representation of the object 

 to the mind. This is the case of all external objects 



