'Philosophy of the Hainan Mind. 19 



irathiTtcle, and the renewed perception correspond- 

 ing with it is called an idea. That vibrations may 

 be revived not only by the repetition of external 

 impressions, but by their association with each 

 other; and that, of vibrations which have been 

 associated together a sufficient number of times, 

 either synchronously, or in succession, if one be 

 excited, it will excite the miniatures of all the rest. 

 This is supposed to furnish a solution to all the phe- 

 nomena of the association of ideas. 



According to this theory, the nerves are divided 

 into two classes, sensory and motory ; the former 

 being the immediate instruments of sensation, the 

 latter of motion. Both originate in the medullary 

 substance of the brain, and their vibrations influ- 

 ence and modify each other. In short, every sen- 

 sation, idea, muscular motion, affection, and in- 

 ternal feeling whatever, is supposed, by Dr. Hart- 

 ley, to correspond with some vibratory state of 

 the medullary substance, so that the one may be 

 regarded as the exDonent of the other/ 



Though this system contains many ideas, which 

 bear a near relation to the theories of Des Cartes, 

 Ma£ebranche, and Leibnitz f and though its 

 two fundamental principles are derived from the 

 works of Newton and Locke, yet the author has 

 a considerable claim to the character of originality. 

 His doctrines, combined as they are, and formed 

 into a fair structure, belong to himself, and cer- 

 tainly present some new and useful truth. It seems 

 to be the opinion of many that he ought to be 

 classed with the materialists of the age, and it is 

 not easy to assign him any other place. This, in- 

 deed, is contrary to his own express declarations. 

 He was apprehensive lest the doctrine of corporeal 



/ Ooservttions on Man, vol. i. See also Belsham's Elements of the Phi' 

 ttsophy of Mind, &c. 8vo. l8oi. 

 "m Observations en Man, vol. i. p. 1 10 and ill, Edit. Lond. I79*« 



