II CONCEPTS OF SPACE AND TIME 33 



pies of the human Reason. According to this view, there- 

 fore, Space and Time are nothing but the necessary forms 

 of man's sensuous perception; they do not exist in external 

 reality, but are imposed by the mind on all objects of sense. 

 While accepting the homogeneous universal Euclidean char- 

 acters which Newton ascribed to Space and Time, Kant 

 denied that they were characters of things or events. If these 

 characters belonged to things, Kant failed to understand how 

 the a priori synthetic character of mathematical knowledge 

 was possible, and he could only explain this fact by making 

 the sensuous form of things a subjective contribution of the 

 mind itself. The universal forms of Space and Time in 

 knowledge were due, not to the things or the world to which 

 they seemed to belong, but purely and simply to the per- 

 ceiving mind which invested all things with them. 



In contradistinction to both these theories, Space and 

 Time in the theory of Relativity as conjoint co-ordinate 

 forms belong both to the mind and to things; and the whole 

 effort of Einstein was to separate the subjective appearance 

 from the objective reality, to separate the relative, variable 

 and disturbing contribution made by the observing mind 

 from the real permanent Space-Time factor which is inher- 

 ent in the physical universe. If the confirmation of theory 

 by facts means anything it must be admitted that Einstein 

 has been singularly successful in his analysis and evaluation 

 of these two subjective and objective aspects of the Space- 

 Time concept. That Space and Time were not, on the one 

 hand, merely subjective conditions of experience as Kant 

 held, nor, on the other, merely objectively given elements 

 for experience as Newton held, but that they were both 

 subjective and objective contributions to experience, might 

 have been the discovery of a sound psychology or episte- 

 mology. But that these two factors of Space and Time have 

 been fused into one synthesis, from which both the subjec- 

 tive and objective elements have been properly sorted out 

 and isolated and valued and rigorously determined, is an 

 achievement of the most outstanding importance not only 

 for science but also for philosophy. It is unnecessary to 



