8 THE LESSON OF EVOLUTION 



changed into another ; and, at last, it was definitely 

 proved that energy was as indestructible as matter, 

 that it was not lost when it was no longer exhibited, 

 but had merely passed into the potential or invisible 

 state. 



Another important result of these investigations was 

 to prove experimentally that matter is inert, and that 

 it exercises no initiative of its own ; that it is moved 

 only by external agencies ; and that, in physics, action 

 and reaction are always exactly equal and opposite ; 

 from which it follows that all material things are 

 under the reign of law. This cannot be taken as a 

 proof that mind is absent from dead matter, for it is 

 possible to conceive mind as present, but unable to 

 manifest itself to us. But the experiments destroyed 

 the supposed basis of fact on which Pantheism had 

 formerly been built, and reduced it to a purely 

 metaphysical speculation. 



If, however, science showed that the original basis 

 of Pantheism was erroneous, it now furnished new 

 evidence which seemed to place that philosophy on a 

 firmer foundation than ever. 



Up to the middle of the last century it seemed pro- 

 bable that the Universe might be eternal. Matter and 

 energy were known to be indestructible, and it followed 

 that the amount of each in the Universe must be fixed 

 and unalterable. Also the mathematicians, Lagrange, 

 Poisson, and Laplace were supposed to have demon- 

 strated that the Solar System was truly a perpetual 

 motion. Even in the earth itself the celebrated 

 geologist, Dr James Hutton, sought, as he said, in vain 

 for any " vestige of a beginning or prospect of an 

 end." So far as could then be seen, the world might 



