EXPLANATORY SCIENCE 197 



description? The answer to this question will throw into 

 proper perspective the distinction between the two types of 

 science. 



NATURE OF EXPLANATION 



Though description and explanation are usually sharply 

 contrasted, there is reason to believe that the distinction 

 between them cannot be made in any absolute way. If one 

 takes the realistic attitude toward science and insists that 

 all explanatory entities exist in the same way as that which 

 they aim to explain, there can be no important difference 

 between description and explanation; description calls 

 attention to the more obvious properties and relations of 

 events, and explanation indicates those which are less 

 obvious. Hence one leaves descriptive techniques when he 

 begins to penetrate beneath the surface, or to get behind 

 apparent phenomena. But even if one takes the positivistic 

 attitude and insists that the task of science is the invention 

 of conceptual devices such as classes, series, and laws, 

 which render nature intelligible through simplification and 

 correlation, there is still no significant distinction between 

 description and explanation; employment of the less elab- 

 orate symbolic tools is called description, and of the more 

 elaborate tools, explanation. These two interpretations 

 suggest that description and explanation are strictly con- 

 tinuous, and that the drawing of any line separating the one 

 from the other is more or less arbitrary. 



Yet there appears to be an important distinction between 

 the two with reference to verification. Both description and 

 explanation are, of course, in terms of symbols, and symbols 

 are verified by their referents. But symbols which describe 

 can be verified directly because their referents are given 

 clearly, while symbols which explain cannot be so verified 

 because the events to which they refer are 'beneath' or 

 "behind" the phenomena. Hence the verification of ex- 

 planatory symbols must be indirect. For example, the 

 description of copper in terms of its toughness, malleability, 



