162 THE PROBLEM OF EVOLUTION 



an interior principle underlying acts of volition 

 and thought, i.e. a simple, intelligent soul. 



2. 'There is in man no simple soul. Analysis 

 reveals to us sensations or perceptions of a simple 

 kind, impressions of such perceptions on the memory, 

 which form the basis of ideas, and connection of 

 these ideas, so as to make complex pictures in the 

 imagination. But the concrete and the abstract 

 ideas have one common source, viz. sensation or 

 perception. The material substratum of the con- 

 nection of sensations and ideas with one another 

 is to be sought in what anatomists call the associa- 

 tive fibres. Perceptions and ideas are closely con- 

 nected with feelings and impulses. This associative 

 theory, thus briefly indicated, does not admit of our 

 assuming the existence of a simple soul.' 



Answer to No. 2. The necessity of the 

 presence of a simple soul in the human body 

 cannot be proved directly, either by intro- 

 spection or by objective experiments, but only 

 by deduction. We must deduce the existence 

 of a soul as the psychical principle from each 

 single psychical act. The simplicity of the 

 soul is deduced from the existence of a simple 

 personal consciousness or self-consciousness, 

 as also from the psychological analysis of the 

 powers possessed by man of forming concepts, 

 judgments, and inferences. 



