226 THE PRESENT IMPORTANCE OF SCIENCE 



paper in general, or lettering in general. The sense-impres- 

 sions received from the printed pages are signs which enable 

 him to conceive of possible sense-impressions and to recall 

 so wide a range of previous impressions and the conceptions 

 derived therefrom, that the reading may effect a profound 

 reorganization of his intellectual life. Starting with sense- 

 impressions past or present, which seemingly constitute 

 our only means of knowing what goes on outside our minds, 

 which are for us the real outside world, our complex mental 

 states are in some way built up, until it is impossible to say 

 whether anything like what we term consciousness could 

 exist in a being conscious of its own existence but devoid 

 of sense-impressions. 



It appears, therefore, that what we call external reality 

 is, for the most part, created within our minds. Natural 

 science is the discovery and systematization of facts whose 

 basis is sense-impressions. Generalization consists in the 

 interpretations we put upon our past and present experience 

 with sense-impressions. A science that consisted of dis- 

 jointed sense-impressions would be one of unrelated facts, 

 whereas true science consists in the putting of simple facts 

 together and obtaining facts of a more complex nature or 

 generalizations. This point of view does not imply that 

 science is merely a static organization of knowledge, al- 

 though the accumulated facts of science may be so regarded. 

 Like an organism, science is something happening. It is a 

 process of finding out the relationship and the order of 

 phenomena in nature. Predictability, based upon this ascer- 

 tainment of order and relationship, is its most important 

 function. 



While the facts of natural science are in the first instance 

 sense-impressions, its field is the content of the human mind. 

 For out of sense-impressions, at first isolated and disjointed, 

 we build up within our minds a theory of the whole which 

 constitutes organized science. When this view is appreciated, 

 one understands why scientists maintain that the facts 



