112 THE LIMITATIONS OF SCIENCE 



he uses mathematical equations as if there were four 

 dimensions to space. The mathematician can employ 

 equations which contain four or any number of vari- 

 ables, but the physicist who desires to deal with an 

 objectively real universe and also to be intelligible is 

 forced to limit himself to the three dimensions which 

 correspond to his powers of measurement of length, 

 breadth, and depth. Lastly, Professor Lewis confuses 

 scientific method utterly by arbitrarily assuming which 

 quantities in an equation shall be treated as variable 

 and which as constant. Thus he says, if the mo- 

 mentum of a body changes, let us suppose that this 

 happens not because its motion changes but because we 

 shall consider its mass variable. Of course anyone 

 can say, let us consider the universe to act as he wishes. 

 But, after all, what is the use when no one believes it 

 does ? Is it any wonder that a gulf is growing not only 

 between men of science and the rest of the world, but 

 also between theorists and those who are still willing 

 to submit their imagination to experience? Such a 

 gulf is certain to continue so long as theorists are 

 willing, and even anxious, to ignore common sense and 

 the facts gained by patient and exact experimenta- 

 tion. 



It is true that my criticism of scientific method has 

 been so far purely destructive. And in that admission 

 may lie the ineffectiveness of the argument to many. 

 Some will say that however weak and vacillating the 



