74 BIOLOGY AND PHYSICAL SCIENCES 



into the orderly system of our experience the 

 impressions caused by the noumenal reality. 

 His immediate successors pointed out that 

 there was no reason left for assuming the 

 existence of things-in-themselves outside of 

 us. These supposed existences are nothing 

 but the ghosts of the world of independently 

 existing matter which Hume had shown to 

 be non-existent. The supposed separately 

 existing finite minds are also not proof against 

 Hume's criticism. We must account other 

 wise for all the variety and 'contingency' 

 of our universe. Both the external world of 

 things and the spiritual world of persons have 

 their existence, somehow or other, in only one 

 Supreme Existence. In the efforts to show 

 in detail how this is so the philosophical 

 movement initiated by Kant exhausted itself 

 for the time ; but we shall have occasion to 

 return later to these efforts. 



We must now look somewhat more closely 

 at Kant's account of how the sensible world 

 comes to appear to us as it does, and what 

 bearing his conclusions, and those of his suc 

 cessors, have on the great biological problem 

 which is the main subject of these lectures. 



