CAUSES AND DETERMINERS IN RADICALLY 

 EXPERIMENTAL ANALYSIS 



PROFESSOR H. S. JENNINGS 

 The Johns Hopkins University 



Even where the experimental situation is clear, disa- 

 greement often exists as to the causes or determiners of 

 given phenomena. For clearing the mind on such mat- 

 ters, as well as for guiding experimentation, the writer 

 has found useful two rules of thought, which are here 

 submitted. The bald statements of the rules will be fol- 

 lowed by a commentary with illustrations. 



Rule 1. Radically Experimental Thinking. — Test all 

 questions or doubtful propositions as to causation, de- 

 termination, explanation, by seeking mentally an experi- 

 ment which, if carried out, would decide the matter. If 

 no such experiment is conceivable, the question is one 

 with which science can not deal. 



Or : Reduce all questions to an experimental situation. 



Ride 2. Causation of Differences. — In seeking causes 

 or determiners, compare two cases and discover to what 

 is due the difference between them. A cause or deter- 

 miner is that which brings about the difference between 

 two specifiable cases. 



1. Radically Experimental Thixkixg 

 "What sort of knowledge is sought in the questions: 

 How is this phenomenon caused or determined? How 

 can we understand or account for this? 



One of the things we desire to know is this : What con- 

 ditions can be found which, if supplied, will produce the 

 thing we are trying to understand ; if changed or altered 

 will change or do away with it? Finding conditions is 

 called observation ; supplying, altering or removing them 

 is called experiment; this question therefore asks for 

 conditions discoverable by observation and experiment. 

 The search for and formulation of such conditions makes 

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