CHAPTER X 



EXPLANATORY SCIENCE 



If there are sciences which are empirical or descriptive in 

 character, it is none the less true that there are sciences which 

 are rational or explanatory in character. Mathematical 

 physics, rational mechanics, and geometry are the most 

 obvious examples of such sciences. It was stated at the 

 close of the preceding chapter that explanatory sciences 

 may be considered as the results of the techniques of dis- 

 covery and of verification in the same way that descriptive 

 sciences are the results of the techniques of classifying, 

 ordering, and correlating; when one endeavors to describe 

 nature he constructs an empirical science, and when he 

 endeavors to explain nature he constructs a rational science. 

 This places verificatory techniques on the same level as 

 techniques of discovery, i.e., as methods through whose 

 application explanatory science takes form. From this point 

 of view it would seem preferable to discuss these techniques 

 before an analysis of explanatory science itself is made. 

 However, the fact that an understanding of verificatory 

 techniques is impossible without an understanding of the 

 general nature of explanation lessens the advantage of this 

 manner of presentation. Consequently, the present chapter 

 will be devoted to an analysis of the meaning of explanation 

 and of the structure of explanatory science, leaving for the 

 ensuing chapter the consideration of the techniques by 

 which an explanatory science becomes corroborated and 

 substantiated. 



Since the key to the understanding of explanatory science 

 lies in the meaning of explanation, this problem affords 

 the logical starting-point for the discussion. What, es- 

 sentially, does one do when he explains, and how is the 

 activity of explanation to be differentiated from that of 



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