Chap. Iir. APPENDIX. 



345 



in many pafTages of his works, that we knov^ nothing except by I- 

 deas. This is thought by many to be one of Plato's vifionary no- 

 tions, his dodrine of Ideas being now generally exploded. But, I 

 think, I have fhown that it is the truth of the matter, unlefs we will 

 hold, with Mr David Hume and fome antient philofophers, that. 

 we have no Ideas at all, but only operate by our Senfes: The confe- 

 quence of which neceflarily is, that we have no knowledge at all j 

 becaufe things perpetually changing and varying, fuch as we per- 

 ceive by our Senfes, cannot be the objeds of knowledge ; nor can 

 we fay that what we affirm of any thing is true, any more than that 

 it is falfe *. 



The next thing I propofed to confider, was the manner in which 

 thofe two faculties operate. And here the difference is moft mani- 

 feft ; for the Animal or Senfitive Nature operates only by the Sen- 

 fes, or the Phantafia, which is a kind of fecondary fenfe, preferving 

 in the Mind the images of fenfible things, and prefenting them to us 

 on occafions ; whereas the IntellecSt, fo far from operatmg by the Sen- 

 fes, or Phantafia, is difturbed by them in its operations, and never 

 operates fo perfedly as when it is entirely difengaged from both. 



And thus it appears that Senfe and Intellect are perfedly diftind, 

 both as to the fubjeds on which they operate, and their manner of 

 operating. 



It is for the purpofe of nllifig that every animal knozi's or per- 

 ceives. After haviqg examined, therefore, the gnoflic powers of 

 the Animal and of the Intelledual Natures, let us next confider their 

 adions and purfuits. And, firft, with refped to the mere animal, 

 it is evident that he purfues nothing but what is conducive, cither to 

 the prefervation of the animal life, or to the continuation of the kind : 

 Vol. III. X X For 



* See what I have fnid upon this fubie<5>, p. 7-. 



