TRUTH 



made to prove or refute experimentally the origin of 

 species. It is quite forgotten that the idea of species 

 is only relative, and that no man of science can give an 

 absolute definition of it. Nor is it less perverse to 

 attempt to apply experimentation to historical problems 

 where all the conditions for a successful application are 

 lacking. 



The knowledge which we obtain directly by observa- 

 tion and experiment is only sound when it refers to pres- 

 ent events. We have to turn to other methods for the 

 investigation of the past — to history and traditions ; and 

 these are less easily accessible. This branch of science 

 has been investigated for thousands of years, as far as 

 the history of man and civilization, of peoples and states, 

 and their customs, laws, languages, and migrations, is 

 concerned. In this, the oral and written tradition from 

 generation to generation, the ancient monuments, and 

 documents, and weapons, etc., furnish an abounding 

 empirical material from which critical judgment can 

 draw a host of conclusions. However, the door to error 

 lies wide open here, as the documents are usually im- 

 perfect, and the subjective interpretation of them is often 

 no clearer than their objective validity. 



Natural history, properly so called, or the study of the 

 origin and past history of the universe, the earth, and its 

 organic population, is much more recent than the history 

 of mankind. Immanuel Kant was the first to lay the 

 foundations of a mechanical cosmogony in his remark- 

 able Natural History of the Heavens (1755), and Laplace 

 gave mathematical shape to his ideas in 1796. Geology, 

 also, or the story of the evolution of the earth, was not 

 founded until the beginning of the eighteenth century, 

 and did not assume a definite shape until the time of 

 Hoff and Lyell (1830). Later still (1866) were laid the 

 foundations of the science of organic evolution, when 

 Darwin provided a sound foundation, in his theory of 



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