PHILOSOPHY OF SCIENCE 25 



enced as a result of this shock. It became self-critical. 

 Geometricians began to ask such questions as the following, 

 which, it should be noted, are not geometrical questions 

 but philosophical, i.e., logical and epistemological. What is 

 meant by the consistency of a system of propositions? 

 Can a system of propositions be consistent and not true? 

 What is truth? Does geometry describe the world? Is space 

 objective, i.e., independent of the knowing activities, and, 

 if so, which space — Euclidean space, Lobachewskian space, 

 or Riemannian space? Thus the geometrician was compelled 

 by the intrinsic inconsistencies of his system to turn his 

 attention to philosophical considerations. When he did so 

 he ceased to be a scientist and became a philosopher, and 

 he created that study which is called "the philosophy of 

 science," or, in this case, "the philosophy of geometry." 



The second example is drawn from the field of physics. 

 At the end of the last century physics was also in a state of 

 great complacency. Though its youth and development had 

 not been so uneventful as that of mathematics, it had reached 

 a stage of relative quiescence. It was generally recognized 

 that the great discoveries in physics had all been made and 

 that progress would consist of the introduction of greater 

 accuracy. The point of view is well expressed by the state- 

 ment in the announcement of courses in the department of 

 physics in one of the great universities of this country near 

 the end of the last century, to the effect that research work 

 in physics in the future would consist essentially in the 

 transformation of physical laws so as to make them accurate 

 to the fourth rather than merely to the third decimal place. 



Then came the shock of the relativity theory. A certain 

 experiment, devised to measure the variations in the velocity 

 of light due to the changes in the velocity of its source, was 

 performed. It was confidently predicted that the anticipated 

 outcome would be verified. But the results were unequivo- 

 cally negative. The crucial character of the experiment 

 made its negative outcome of great significance. Ordinarily 

 when an hypothesis fails of verification the scientist throws 



