THE SENSATIONALIST PHILOSOPHY. 4iOB 



the slightest pretence. What he thought of was communication along 

 a line of minute particles some impulse, given at the external organ 

 of sense, much in the manner of what we see to take place in a series 

 of elastic balls. Our modern knowledge might suggest ideas of com- 

 municated action, not mechanical, which might help us on this subject 

 and have indeed more recently been applied, though not always wisely, 

 and within proper limits. But what Hartley proposed gave as good a 

 notion of the real nature of the process as has ever yet been obtained, 

 although modifications in the mode of expression might now be found 

 expedient. We must, however, always recollect that the whole real 

 importance of Hartley's physical theory is contained in these pro- 

 positions : 1. That sensations belong to a specific action of the nerves 

 and brain. 2. That revivals of sensations, called ideas, depend on a 

 similar but less vivid or less extended action. 3. That ideas arise 

 according to regular laws depending on the nature bf nervous matter, 

 and on a physical sympathy between similar contemporaneous or im- 

 mediately successive excitements — giving them such mutual power 

 over each other that the recurrence of one will bring up the idea of 

 the other. These are propositions in themselves by no means improb- 

 able, and which have been independently supported by much curious 

 evidence. 



Whether the system be right or wrong we may safely conclude 

 that the ridicule heaped upon Hartley's physical theory was totally 

 misplaced, and originated in the blundering ignorance and prejudice 

 of those who employed it. 



I readily acknowledge that Dr. Hartley's attempt to digest his 

 system into propositions and corollaries in mathematical form was 

 injudicious ; that his frequent recurrence to his vibration theory after 

 he had once explained its evidence and purport was tiresome and 

 repulsive, and that his style was far from being attractive ; but I con- 

 tend at the same time that in educing all mental states from sensations 

 according to one fixed law, of which all supposed distinct faculties are 

 but special cases, he has attained to the true interpretation of the 

 nature of the mind, and has presented the principles of philosophy in 

 their simplicity and grandeur in a way which ought to command the 

 attention of thoughtful men, and which affords the best foundation 

 for practical usefulness. 



The mind which first perceived the real importance and extent of 

 ^application of the law of association must have belonged to the highest 



