m THE ORIGIN OP THE IMPRESSIONS 101 



All the melodies and harmonies that proceed 

 from the piano depend upon the action of the 

 musician upon the keys. There is no internal 

 mechanism which, when certain keys are struck, 

 gives rise to an accompaniment of which the 

 musician is only indirectly the cause. According 

 to Descartes, however and this is what is gener- 

 ally fixed upon as the essence of his doctrine of 

 innate ideas the mind possesses such an internal 

 mechanism, by which certain classes of thoughts 

 are generated, on the occasion of certain experi- 

 ences. Such thoughts are innate, just as sensations 

 are innate; they are not copies of sensations, any 

 more than sensations are copies of motions; they 

 are invariably generated in the mind, when certain 

 experiences arise in it, just as sensations are in- 

 variably generated when certain bodily motions 

 take place; they are universal, inasmuch as they 

 arise under the same conditions in all men; 

 they are necessary, because their genesis under 

 these conditions is invariable. These innate 

 thoughts are what Descartes terms " verites " or 

 truths: that is beliefs and his notions respecting 

 them are plainly set forth in a passage of the 

 " Principes." 



"Thus far I have discussed that which we know as 

 things : it remains that I should speak of that which we 

 know as truths. For example, when we think that it is 

 impossible to make anything out of nothing, we do not 

 imagine that this proposition is a thing which exists, or a 

 property of something, but we take it for a certain eternal 



