146 Science Religion and Reality 



of that achievement it is not necessary to enter here. But thereby 

 Newton placed in men's hands a lav/ whose writ was universal. 

 The law of the heavens was now the law of earth. 



During the century and a half that has elapsed since the publi- 

 cation of the law of universal gravitation, science has developed 

 prodigiously along the same lines. In reliance on the universality 

 of natural law the stars have been measured, weighed, and analysed. 

 The same scientific process directed to our own planet has traced 

 its history, determined its composition, demonstrated its relation 

 to other bodies. The investigations of the physicist and chemist 

 have suggested a structure in terrestrial matter similar to that of 

 the stars and suns. The whole has been reduced to a unitary 

 system. Living things have been examined with greater and 

 greater powers of analysis and magnification. Among them, too, 

 Law has been found to rule. The wild creature is a subject of 

 law ; the migration of the bird that is as " free as air " can be 

 predicted as well as the process of digestion, as well as a chemical 

 reaction. 



In this century and a half of vast experimental activity, where- 

 ever men have looked they have found law. It has always been a 

 question of looking skilfully enough and patiently enough, for law 

 to emerge. Yet it is true that there are certain important gaps 

 which must be recognised. Thus, no real link has been shown 

 to exist between the living and the not-living. Despite the 

 extension of our knowledge of the physics and chemistry of the 

 animal body, it yet remains that, as far as we can see, Aristotle was 

 right in the sharp distinction that he made between life and not- 

 life. But the acceptance of vitalistic theory does not imply the 

 absence of natural law governing living things, and all seems as 

 determinate within living things as outside them. There are laws 

 of heredity as much as there are laws of chemical combination. 



In the second half of the nineteenth century the view gained 

 currency that species were impermanent and that man himself was 

 descended from lower forms. Despite the commotion that this 

 doctrine evoked it introduced no fundamentally new factor. That 

 human bodies may be investigated as though they were mechanisms, 

 the laws of whose working are progressively discoverable, had been 

 known in antiquity and had been amply demonstrated by such later 

 workers as Harvey, Stephen, Hales, and Claude Bernard, That 

 the structure of man was comparable to that of the lower animals 



