SCIENTIFIC DISCOVERY 175 



suggested in the preceding chapter, modified positivism in- 

 sists that hypotheses are invented, while realism maintains 

 that they are discovered. The essential difference seems 

 to be that invented entities do not exist prior to the act of 

 invention, and hence seem to exist only because of the act; 

 but discovered entities do exist prior to the act of discovery, 

 and hence do not seem to exist merely because of the act. 

 However, though this may be a genuine distinction, it is not 

 relevant here; so long as one confines his attention to the 

 mental operations by which the symbols for such entities are 

 called into consciousness, the question as to whether or not 

 anything corresponds to the symbols is unimportant. That 

 the invented or discovered entities exist first merely as con- 

 cepts would be granted by both modified positivists and 

 realists; differences arise only when the further question of 

 the existence of the referents of the concepts is raised. 

 Hence one may formulate the problem here, indifferently, 

 as the problem of scientific discovery or as the problem of 

 scientific invention. 



ACT OF DISCOVERY 



The generally creative character of the act, and its in- 

 timate association with the fact of imagination, have been 

 well recognized. " The physicist is bound, by the very nature 

 of the task in hand, to use his imaginative faculties at the 

 very first step he takes. For the first stage of his work must 

 be to take the results furnished by a series of experimental 

 measurements and try to organize these under one law. 

 That is to say, he must select according to a plan which 

 will in the first instance be hypothetical and therefore a 

 construction of the imagination. And when he finds that the 

 given results will not fit into one plan he discards it and tries 

 another. This means that his imaginative powers must 

 always be speculating on the significance of the data which 

 have been furnished through experimental measurements." 1 

 Faraday, whose researches are responsible for much of the 



1 M. Planck, Where Is Science Going?, pp. 86-87. 



