GENERAL DEFINITION 39 



types, perhaps from one, the present large number and ' 

 diversity of species being due to progressive modifica- 

 tions of earlier species, brought about by natural forces 

 and laws which still operate. This theory includes 

 in its reference both the animal and vegetable king- 

 doms, and claims in particular to describe the produc- 

 tion of the human organism. Some evolutionists hold 

 that the development of species is fully accounted for 

 by the operation of natural forces and laws. But 

 others acknowledge that natural evolution has been 

 attended by involution, that is, by superphysical causa- 

 tion, which has determined the upward direction and 

 the results of the operation of natural forces. Those 

 who deny the superphysical factors have obviously 

 been controlled in their opinion by the philosophy 

 which I discussed in my first lecture — the philosophy 

 of naturahsm. Physical data do not and cannot, of 

 themselves, disprove the working of superphysical 

 causation. 



Such in general is the evolutionary theory. It 

 should not be confused with particular explanations 

 of the method of origin of new species, such as the 

 theories of Lamarck and of Darwin; nor with wider 

 theories which profess to explain the development of 

 the inorganic world, and the progress of human his- 

 tory, thought, and rehgion, by an exclusively natural 

 evolution.^ The word "evolution" cannot be used to 



1 Prof. Le Conte, Evolution in Relation to Religious Thought 

 (2d ed.), p. 8, defines evolution to be "a continuous progressive change 

 according to certain laws, by means of resident forces," — a natural- 



