THE EVOLUTION OP THE IDEA OP EVOLUTION 7 



The narrow limits of the little medieval universe were 

 thrust back indefinitely. The crystal globes that were 

 thought to have hemmed it in were shattered by 

 Copernicus and Galileo, and the stars sank back into 

 profound abysses of space. Before the end of the 

 eighteenth century the idea of evolution was again 

 peeping timidly out of the pages of scientific writers. 

 Buffon, the great French naturalist, very clearly held it 

 in principle, but there were still too many censors in 

 France to permit him to develop it. Rousseau made 

 men familiar with the idea of the social evolution of 

 humanity. In England Erasmus Darwin, born in 1788, 

 boldly advocated development, and anticipated more 

 than one idea of his more celebrated grandson. He 

 noted the unity of plan in all animals, the metamor- 

 phoses of animals like the frog or the butterfly, and the 

 changes wrought in animals by artificial selection and 

 climatic variations. These things, he said, pointed to a 

 common descent of all living things from some primitive 

 " living filament." 



From the side of astronomy and geology the principle 

 of evolution was being slowly established. In 1755 the 

 greatest of German philosophers, Immanuel Kant, then 

 a young man of more scientific than philosophic temper, 

 had published the germ of the nebular theory or the 

 condensation of the heavenly bodies out of a thin and 

 far-scattered mist of gaseous matter. His little work 

 attracted no attention, and was in fact completely for- 

 gotten for nearly a hundred years. In the meantime 

 the brilliant French astronomer and mathematician, 

 Laplace, impressed the theory on the cultivated mind of 

 Europe by his full and powerful elaboration of it. Since 

 that time he issued his Exposition of the System of the 

 World in 1796 the principle of evolution has had a firm 

 base. His theory has naturally had to undergo a good 



