326 NERVOUS SYSTEM. 



in the human being progressing from infancy to adult life ; 

 and finally, the psychological philosopher attempts, by intro- 

 spective observation, to study the workings of the perfect 

 intellect, his only means of investigation being the very in- 

 telligence he is endeavoring to comprehend. 



If it were possible to bring to bear upon speculative phi- 

 losophy the same positive methods employed with success in 

 most of the natural sciences, the results of the study of the 

 mind would be much more definite ; for we would then be 

 able to eliminate much that is purely hypothetical, resting 

 on no established basis in fact. As we are studying the 

 mind itself with the mind, and as many psychologists en- 

 deavor to submit their ideas to the test of personal expe- 

 rience, it is necessary that the investigator should be entirely 

 free from the disturbing elements of intellectual inaccuracy 

 or unjustifiable prejudice ; but, unfortunately, the effects of 

 early impressions made by faulty education are not often en- 

 tirely removable ; and notions that apparently can never be 

 supported by facts are apt to take the place of sound philo- 

 sophic reasoning. Ideas of this kind might, perhaps, be ra- 

 tionally entertained and discussed at a period when our posi- 

 tive physiological knowledge amounted to almost nothing, 

 as before the discovery of the circulation, when our literature 

 was filled with disquisitions upon the generation of the "spi- 

 ritus" the location of the passions, etc. ; but as knowledge 

 has advanced and as established facts are more and more nu- 

 merous and available in the study of mental phenomena, the 

 range of pure speculation should become more and more re- 

 stricted. 1 



At the present day, we are in possession of a sufficient num- 

 ber of positive facts to render it certain that there is and can 



1 A striking example of rapid advance from the most vague and absurd 

 mysticism toward positive physiological knowledge is afforded by a comparison 

 of the "(Eeonomia Regni Animalis" written by Swedenborg, one of the most 

 learned men of his day, in the middle of the eighteenth century, with the great 

 work by Haller (Elemenla Physiologice), published only a few years later. 



