CHAP, n CONCEPTS OF SPACE AND TIME 23 



give no constant results. Applying the conclusion to gravitation 

 and the rotational movements of the universe, we find that the 

 Space-Time medium of the universe is curved and warped and not 

 of the homogeneous character which was attributed to Space and 

 Time according to the old ideas. In all gravitational fields events 

 happen in curves and follow the fundamental curves of the Space- 

 Time universe. The result is that the entire universe acquires a 

 definite structural character, and is not a diffuse homogeneity as 

 was formerly supposed. According to the new Space-Time con- 

 cept, structure, definite organised structure, becomes the essential 

 characteristic of the physical universe, and this structural char- 

 acter accounts for many hitherto inexplicable phenomena. 



In the preceding chapter I have tried to explain how the 

 acceptance of the theory of Evolution must inevitably and 

 profoundly affect our views as regards the nature of matter. 

 In this chapter I proceed to inquire what bearing recent 

 far-reaching physical researches and speculations have on 

 this position. Our problem is to break away from the hard 

 and narrow conceptions of the Victorian age, to see Nature 

 once more in her fluid and creative plasticity, and to formu- 

 late our conceptions afresh from this deeper point of view. 

 A great change has come over our views of Nature, a change 

 great enough in the end to amount to one of the fundamental 

 revolutions in human thought. But we are still in the 

 process of that change, and it is therefore difficult for us to 

 realise its full significance. Three dates stand out in bold 

 relief as inaugurating that change: 1859, when Darwin's 

 Origin of Species was published; 1896, when Becquerel dis- 

 covered Radioactivity; and 191 5, when Einstein published 

 his General Theory of Relativity. Round these three great 

 events other discoveries of profound interest have taken 

 and are still taking place; and in the result our entire view- 

 points and standpoints as regards Nature and reality are 

 undergoing a fundamental change which must in the end 

 affect every province of human thought and conduct. The 

 fixity of organic species is gone; the fixity of inorganic 

 elements is going. The position is once more becoming 

 fluid, the old rigid order is visibly dissolving, the fixed land- 

 marks and beacon-points by which former generations 



