14 



doctrine of association. He, therefore, thinks it reasonable to 

 suppose that these two, containing the ' 'laws of the bodily and 

 mental powers respectively, must be related to each other, 

 since the body and mind are' '. l But, as he says in the preface, 

 the reader should not expect ' 'more than hints and conjectures 

 in difficult and obscure matters' '. 2 In other words, Hartley's 

 suggestion amounts to, first, a correlation of the vibrations of 

 certain parts of the body, and the association of ideas in the 

 mind. He assumes that the two are quite parallel, and that 

 as any particular vibration in the brain will be dependent upon 

 the previous and simultaneous conditions of the brain, so also 

 will any operation of the mind be dependent upon the previous 

 and simultaneous mental conditions. From this results his 

 doctrine of the mechanism of the human mind, which he states 

 as follows: "By the mechanism of human actions I mean 

 that each action results from the previous circumstances of 

 body and mind, in the same manner, and with the same cer- 

 tainty, as other effects do from their mechanical causes". 3 

 ' 'Every action, or bodily motion, arises from previous circum- 

 stances, or bodily motions, already existing in the brain, that 

 is, from vibrations, which are either the immediate effect of 

 impressions then made, or the remote compound effect of 

 former impressions, or both." 4 



The really important thing to notice in Hartley is, that 

 while he does not explicitly assert a causal connection between 

 the thought processes, or association, and the brain, he quite 

 evidently assumes something very like it; and, however logical 

 his development of association may be on the basis of the mater- 

 ials which he used, that is, the theory of simple ideas, it certainly 

 cannot be held that he made a serious investigation of the 

 processes of thought before he assumed that this theory, or the 

 theory of association, was correct. Viewed critically, from the 

 standpoint of Hartley himself, his whole account of the physio- 

 logical process and the mental, is what one might regard as 

 perfectly legitimate speculation, but still speculation rather 

 than proof. That seems to be Hartley's own view of his work, 

 and as such it is important, because it seems to be the fact 

 that some of his successors regarded his theory as evidently 

 established rather than as merely proposed. 



KXC. p. 6. 

 2 O.C. preface, p. iv. 

 3 O.C. p. 500. 

 4 O.C. p. 501. 



