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THE RELATION OF SENSE-DATA 

 TO PHYSICS 



I. THE PROBLEM STATED 



OHYSICS is said to be an empirical science, based 

 A upon observation and experiment. 



It is supposed to be verifiable, i.e. capable of calcu 

 lating beforehand results subsequently confirmed by 

 observation and experiment. 



What can we learn by observation and experiment ? 



Nothing, so far as physics is concerned, except imme 

 diate data of sense : certain patches of colour, sounds, 

 tastes, smells, etc., with certain spatio-temporal rela 

 tions. 



The supposed contents of the physical world are prima 

 facie very different from these : molecules have no colour, 

 atoms make no noise, electrons have no taste, and cor 

 puscles do not even smell. 



If such objects are to be verified, it must be solely 

 through their relation to sense-data : they must have 

 some kind of correlation with sense-data, and must be 

 verifiable through their correlation alone. 



But how is the correlation itself ascertained ? A cor 

 relation can only be ascertained empirically by the cor 

 related objects being constantly found together. But in 

 our case, only one term of the correlation, namely, the 

 sensible term, is ever found : the other term seems essen- 



