CHAPTER II 



THE NATURE OF STIMULATION 



Contents: Principles of scientific knowledge and research. Origin and 

 meaning of the conception of cause. Cause and condition. Criticism 

 of the conception of cause. The conditional point of view. Con- 

 ception of cause. The conditional point of view applied to the investi- 

 gation of life. Conception of vital conditions. Definition of the 

 conception of stimulation. 



The common problem of all scientific research is the investi- 

 gation and formulation of natural laws. The assumption of a 

 unity in the happenings and of existence in the world, in accord- 

 ance with definite laws, forms the indispensable foundation of all 

 scientific study and is fully justified by experience. Experience 

 has taught us, as a result of innumerable individual observations, 

 the existence of such an accordance, whereas in not a single 

 instance has it been shown that this is not the case. We are thus 

 justified in assuming without further discussion that every scien- 

 tific research, every new problem which we approach, is likewise 

 founded on this unity of occurrences in accordance with natural 

 laws. Only on the firm basis of this assumption has scientific 

 investigation a purpose, and every success is a new proof of this. 

 There is an unanimity of opinion concerning this among scientific 

 investigators in all fields. 



Not such complete agreement, however, exists in regard to the 

 question by what symbols of human thought and speech these 

 laws can be described in part as well as in toto, so that existing 

 laws can not only be fully and conclusively defined, but at the 

 same time without the use of superfluous terms. According to 

 Ernst Mach, thought is an adaptation to facts. Our speech is 



