PHILOSOPHICAL AND PSYCHOLOGICAL ASPECTS 237 



and difference of opinion, it is because science no sooner 

 gets a fact tolerably well established than it proceeds to 

 other facts. While we agree upon the interpretation of cer- 

 tain data, conflicting data may be adduced at any time; or 

 we may undertake entirely new lines of investigation, which 

 for a time yield uncertain results. Having satisfied ourselves 

 as to the general course of development in the individual, 

 and having a common agreement regarding the same, we 

 press on to something new, like the problems of fertiliza- 

 tion and of differentiation. Here, we find ourselves upon 

 ground where the facts are so sparsely established that we 

 are unable, for the present, to discover a common-sense 

 basis on which to formulate a theory. Divergent views exist 

 in science only because the life of science is progress, and 

 because science concerns itself with what is to be done rather 

 than with what has been accomplished. Divergent opinions 

 frequently eventuate in agreement as soon as the facts are 

 known and established. 



The function of the subjective process in the advance- 

 ment of science now becomes clear. The fundamental clas- 

 sification of human thought is along the lines of subjective 

 and objective reality. A so-called normative science like 

 logic deals with the operations of the subjective element in 

 its manipulation of facts and cannot of itself alone lead to 

 new truth regarding a supposedly external reality, although 

 it may discover more effective methods of handling the facts 

 of sense-impression. The popular suspicion that the logician 

 is merely juggling with words, even when his methods are 

 sound, seems to rest upon conviction that the technique 

 of reasoning is no more than a tool and therefore subordinate 

 to the material upon which it works. Belief that the human 

 mind can obtain knowledge of any so-called external or 

 objective reality, by means that are wholly subjective, is 

 repugnant to the thought of natural science as well as to the 

 common sense of mankind. 



