2 THE LESSON OF EVOLUTION 



every possible action is counter-balanced by other 

 actions, energy will practically disappear. 



From this theory of " dissipation of energy " it 

 follows that, as the earth is cooling, life cannot go 

 on for ever ; and also that at some former time the 

 Earth must have been too hot for the existence of 

 protoplasm. Consequently life can only have a 

 limited existence on the earth. It must have had a 

 beginning and it must come to an end. 



But the inference extended further. Not only 

 living beings but even the whole Solar System must 

 have had a beginning, not infinitely remote ; because 

 most of its members still contain a large amount of 

 their original heat. And if the Solar System had a 

 beginning, so also must each star in the heavens 

 have had a beginning ; for the very fact that we can 

 see them is a proof that they are radiating out 

 energy. And, it was asked, why should not the 

 whole Universe, visible and invisible, have had a 

 common origin and a common beginning in time? 

 This had been the opinion of Immanuel Kant in the 

 middle of the eighteenth century; and, although 

 modern astronomy has not altogether confirmed his 

 speculations, it has proposed an hypothesis which is 

 not very dissimilar. This is the " Meteoritic 

 Hypothesis," which was first suggested in 1848 by 

 J. E. Mayer, but which is chiefly the work of Sir 

 Norman Lockyer and Professor G. H. Darwin. I 

 will give a short sketch of the views held by the 

 former. 3 



3 See the "Meteoritic Hypothesis," Macmillan, 1890; and 

 " Inorganic Evolution," Macmillan, 1900. 





