THE NATURE OF PHYSICAL REALITY 



The origin of mental processes is so deep-seated 

 in the elementary structure of living matter that 

 there should exist the closest congruity between 

 the conclusions of the mind and the underlying 

 principles of physics and chemistry. The activi- 

 ties of natural forces have been found, in general, 

 to proceed consistently with the principles of 

 mathematics, and it is a significant fact that 

 mathematical truths are also the only truths 

 which are self-evident to the human mind. There 

 are, however, a few peculiar cases where the con- 

 clusions of the mind have appeared to be contrary 

 to actual facts, or where the mind seems to have 

 been incapable of forming a correct conception of 

 the true nature of physical reality. Foremost 

 among such cases are the imaginary even roots of 

 negative numbers, the paradoxical special prin- 

 ciple of relativity which states that the velocity of 

 light is independent of the relative velocity of ob- 

 server and source, the supposed curvature of 

 space, and the ultimate nature of matter and 

 electricity. 



The existence of imaginary quantities in algebra 

 is the result of certain conventionalities which 

 have been adopted for the solution of equations, 



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