104 THE EIDDLE OF THE UNIVERSE. 



crime, from which he longed to free himself as soon 

 as possible." In fact, the most important systems of 

 psychology are completely opposed to each other in 

 the two editions of Wundt' s famous Observations. In 

 the first edition he is purely monistic and materialistic, 

 in the second edition purely dualistic and spiritualistic. 

 In the one psychology is treated as a physical science, 

 on the same laws as the whole of physiology, of which 

 it is only a part ; thirty years afterwards he finds 

 psychology to be a spiritual science, with principles 

 and objects entirely different from those of physical 

 science. This conversion is most clearly expressed in 

 his principle of psycho-physical parallelism, according 

 to which " every psychic event has a corresponding 

 physical change"; but the two are completely indepen- 

 dent, and are not in any natural causal connection. This 

 complete dualism of body and soul, of nature and 

 mind, naturally gave the liveliest satisfaction to the 

 prevailing school-philosophy, and was acclaimed by 

 it as an important advance, especially seeing that it 

 came from a distinguished scientist who had previously 

 adhered to the opposite system of monism. As I 

 myself continue, after more than forty years' study, 

 in this " narrow " position, and have not been able 

 to free myself from it in spite of all my efforts, I 

 must naturally consider the " youthful sin " of the 

 young physiologist Wundt to be a correct knowledge 

 of nature, and energetically defend it against the 

 antagonistic view of the old philosopher Wundt. 



This entire change of philosophical principles, which 

 we find in Wundt, as we found it in Kant, Virchow, 

 Du Bois-Reymond, Carl Ernst Baer, and others, 

 is very interesting. In their youth these able 

 and talented scientists embrace the whole field of 



