152 Wisconsin Academy of Sciences^ Arts, and Letters. 



then, are the essential elements in the formation of any perception? 

 Before all, something must be impressed upon the consciousness. 

 Sensations depend solely upon the nerves to convey them to the 

 conscious subject. Any interruption of their career toward the 

 brain puts an end to them, or rather, there being no sensation in 

 the consciousness, none exists anywhere. If, therefore, sensation 

 is essential to perception, then nerves are likewise essential. But 

 nerves are only the menial organ which serves mysteriously lo con- 

 vey impressions to the mind, without, in ordinary perceptions^ 

 revealing themselves^to the consciousness. Some perceptions, more- 

 over, sach as the perception of relations, are generally recognized 

 as being independent of all sensation. So, too, causation, time, 

 and identity, must be perceived, if at all, without the help of any 

 mechanism, since in their nature they are impalpable. No par- 

 ticular character in the object, therefore, can be pronounced es- 

 sential to mental perception ; immaterial principles are perceived 

 as clearly as granite hills. 



It thus appears that the practical objective conditions which 

 now limit perception may be purely casual. Only two elements 

 remain which can be shown to be essential in the perception of all 

 things objective. These are feeling and reflection ; feeling, be- 

 cause it is the condition of both sensation and consciousness, and 

 whatever is not felt in either of these ways cannot in any manner 

 make itself known ; and reflection, because feeling is not thought, 

 and no knowledge can result from feeling simply as feeling, any 

 more than we can become cognizant of a present physical object 

 without looking upon it to discover its qualities. Keflection in- 

 terprets feeling into terms of thought. This is done spontaneously, 

 to be sure, and seems to attend rather than follow the feeling — 

 what obviously follows being inference rather than intuition. 



Both these essential conditions being met, the source or cause of 

 the feeling does not affect the validity of the consequent percep- 

 tion. The feeling itself is sufficient evidence of the actuality of 

 its cause; its nature is a distinct problem. "Whoever says he 

 knows," observes Jacobi, " we properly ask him whence he knows. 

 He must then depend at last upon one of these two things, either 

 upon sensation or upon soul-feeling." All knowledge resting on 



