PHILOSOPHICAL AND PSYCHOLOGICAL ASPECTS 231 



sions that are justified by the facts of objective experience 

 is performing a scientific act. The man of the street and 

 the man of the farm have much in common with the scientist, 

 though the latter may seem to them to be both fool and 

 dreamer. 



As there may be some question regarding the meaning 

 of the term "common sense," we may agree at the outset 

 that a man has common sense when he deals rationally with 

 the facts of his experience. The man of common sense sees 

 the whole situation or, as the scientist would put it, he con- 

 siders all the data and draws his conclusions therefrom. We 

 think a man's judgment sound, if he does what a well-bal- 

 anced individual would be expected to do when confronted 

 with all the details of a particular situation. The theorist 

 fails if he does not consider the workaday elements of the 

 case. The practical man fails if he judges solely by rule-of- 

 thumb and without the light of theoretical considerations. 

 Now science has gone forward in the past, not by wizardry, 

 but by the application of this all-sided sense in the solution 

 of its problems. The methods of thought which advance 

 science do not differ in kind from those of the most hard- 

 headed man of affairs who creates a business of international 

 proportions. 



The owner of a quarry uncovers a layer of rock different 

 in appearance from any before offered for sale in his locality. 

 Lacking expert advice, he begins to experiment and to make 

 observations, with a view to determining the utility of the 

 new material. After subjecting it to a variety of tests, he 

 concludes that the stone can be put to certain uses. It is 

 good for crushing and for rough masonry, but not for sills 

 and lintels; good for road foundations, but not for surfacing. 

 In reaching these conclusions, he first establishes certain 

 facts; then compares these with facts previously known; 

 then classifies the stone as good or bad for a given purpose; 

 and thus arrives at the conclusion that a stone of this na- 

 ture may be put to certain uses. He is now in a position 



