Source of Error in studying Mental Action. 91 



only in proportion as man becomes enlightened by- 

 extension of new scientific knowledge, especially in 

 physiology, will he be able to view himself in a true 

 aspect apart from his consciousness. Science pene- 

 trates deeper than metaphysical speculation, into the 

 nature of mental action, chiefly because metaphysics 

 deals only with old ideas, whilst science furnishes us 

 with new experience and therefore with new concep- 

 tions and wider evidence. 



Fallacies are very prevalent, every subject of human 

 study is liable to a very large class of errors arising 

 from the extremely imperfect state of our knowledge, 

 and in very few subjects is our ignorance as great as 

 in that of mental and moral phenomena. Every 

 different subject of study also, has, in consequence of 

 its special peculiarities, its own peculiar class of 

 fallacies, into which the student of it is likely to be 

 led, unless he is previously guarded against them. 

 In accordance with this truth, the study of man's 

 nature, especially the mental and moral portions, is 

 particularly liable to a class of errors arising from the 

 circumstance, that the phenomena to be observed and 

 the observing power are intimately connected to- 

 gether, each influencing and disturbing the other- 

 The obstacles to our arriving at truth in the study of 

 mental and moral actions, are greater and more 

 frequent, the more nearly and intimately related the 

 phenomena to be observed and contemplated, are to 

 the observing and contemplating faculty, or rather to 

 the contemplative action. When the two mental 





