268 THE HISTORY OF SCIENCE 



worthy to command respect ; but it may not lie be- 

 yond the possibility of explanation. Like ethical 

 insight, or spiritual illumination, the scientific idea 

 comes to those who have striven for it. The door may 

 open after we have ceased to knock, or the response 

 come when we have forgotten that we sent in a call ; 

 but the discovery comes only after conscious work. 

 The whole history of science shows that it is to the 

 worker that the inspiration comes, and that new 

 ideas develop from old ideas. 



It may detract still further from the mysterious- 

 ness of the discovery-process to add that the illu- 

 minating idea may come in the midst of conscious 

 work, and that then also it may appear as a sudden 

 gift rather than the legitimate outcome of mental 

 effort. T^he spontaneity of wit may afford another clue 

 to the mystery of scientific discovery. The utterer of 

 a witticism is frequently as much surprised by it as 

 the auditors, probably because the idea comes as 

 verbal imagery, and the full realization of their sig- 

 nificance is grasped only with the actual utterance of 

 the words. The fact that to the scientific discoverer 

 the solution of his problem arrives at the moment 

 when it is least sought is analogous to the common 

 experience that the effort to recall a name may in- 

 hibit the natural association. 



The tendency to emphasize unduly the role played 

 by the scientific imagination springs probably from the 

 misconception that the imagination is a psychological 

 superfluity, one of the luxuries of the mental life, 

 which should not be withheld from those who deserve 

 the best. The view lingers with regard to the aesthetic 

 imagination. James could not understand the biologi- 



