628 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



as far as sense impressions, the origin of thoughts and emotions and their 

 effects are involved, represent the subject matter of psychology. As a further 

 step we recognize in our outer world other human organisms, consisting of 

 physiological and psychological factors similar to our own, while other living 

 organisms — animals and plants — show graded differences from ourselves. 

 The physical-chemical, non-living environment, as well as the world of living 

 organisms, except ourselves, represents then our outer world, while we, 

 with our sense impressions, feelings, thoughts, emotions, wills and desires 

 represent our inner world. 



Thus our inner and outer worlds both consist to a large extent of the same 

 psychical elements, our sensations; also, both worlds are composed of the 

 same physical-chemical elements and this is true of all organs and tissues of 

 the body, including those on whose functions our psychical activities depend. 

 In the physical and psychical realms, the outer world and "we" are consti- 

 tuted of the same elements. Sense impressions stand on the borderline between 

 inner and outer world, and they, with our thoughts, represent a combination 

 of environmental and inner organismal factors. It is by means of sense 

 impressions that we construct both worlds and connect the two. With their 

 aid we build an outer world, to which we attribute an existence independent 

 of our own organism as a separate external reality, which we take for proven 

 because of the fact that our interpretation of things and our prediction of 

 future events, made on the basis of our thought-constructions, may prove 

 correct, and also because of the fact that this reality is experienced in the 

 same way by all human beings who have adequate knowledge and under- 

 standing. 



We believe that we are aware of our inner world directly, without the 

 intervention of our sense organs, while we realize that we recognize the 

 outer world by means of these sense organs. The inner world constitutes for 

 us our real individuality, and especially those parts of our inner world 

 centering around the concept "I," which latter again is gained by means of 

 abstractions and synthesis, like other thoughts. As far as our psychical 

 elements undergo within us variations which we do not fully understand, 

 and which are different at different times and which may differ in different 

 individuals under apparently the same conditions, they are considered as 

 subjective. The outer world is considered as objective, independent of 

 changes within us, and to a higher degree constant. This is one of the reasons 

 why we make such distinctions as outer and inner world. 



Through the interaction between the outer world and our sense organs we 

 become aware of events, which are singled out and differentiated from 

 others and compared with similar preceding ones. Events then become pre- 

 dictable; the sense organs appear, thus, to be constant, identical at different 

 times in the same person in the same environment, and also identical in 

 different persons; they seem largely independent of other parts of our 

 variable organism. Those sense experiences which are common to all humans, 

 which are reproducible and which represent, therefore, a mechanism, we 

 tend to refer to the outer world. On the other hand, thoughts and emotions 



