1 64 THE EVOLUTION OF MAN 



society than in the case of the body or mind of man. Within 



historic times the social instincts of men have not changed 



more fundamentally than their intellectual capacities or their 



germ-plasm. 



Unlike any other form of evolution, the rapid changes which 

 are taking place in human society are not due to changes in 

 germ-plasm, nor even to changes in the developed individual, 

 but merely to changes in environment. They are not even 

 skin-deep, they are only clothes-deep. It may be questioned 

 whether these changes are really evolutionary at all since they 

 do not involve changes in germinal inheritance, intellectual 

 capacity, or social instincts, but are merely the accumulation of 

 experiences from generation to generation, as an individual 

 accumulates knowledge from year to year. Indeed, the prog- 

 ress of human society is much more like the development of 

 an individual than it is like the evolution of a species. 



But whether we regard social development as a form of 

 phylogeny or of ontogeny, as a result of inheritance or of 

 environment, we cannot fail to see that it is going forward at 

 a rapid rate and that it is fraught with the most stupendous 

 possibilities for the future. The only great progress which 

 the human race has made during the past twenty thousand 

 years has been social, and so far as we can now see into the 

 future the progressive evolution of mankind must depend to 

 a great extent upon society. It is particularly in the field of 

 discovery and invention that progress has been most notable. 

 Nothing could more strikingly illustrate this than the compari- 

 son of the state of the world one hundred years ago with that 

 of to-day. Whole regions of the universe have been explored, 

 the very existence of which was not dreamed of a generation 

 ago. Inventions which would seem incredible or magical were 

 they not so common are everyday conveniences. Diseases and 

 epidemics which were once regarded as the direct acts of an 

 inscrutable Providence or of unscrupulous demons are now 



