NATURE, HISTORY, AND ETHICS 399 



when we seek to determine this process of evolution 

 in detail we have to use a different method from that 

 of physical science. We must act on the historical 

 method. In point of fact, we rely on documents, as 

 the historian does. They share the character of all 

 documents of being less valuable the more remote 

 they are.^ 



It is not our purpose here to study the principles 

 of the historical method. The historian is equally 

 unable to represent the incalculable diversity of reality. 

 He must select definite points. He will choose 

 particular events — or, as every individual thing is 

 itself too vast to comprehend — certain particular 

 events. 



* The objection is raised that Professor Haeckel has been 

 endeavouring for some forty years, with very moderate success, to have 

 the natural sciences called "historical" instead of merely "descriptive" ; 

 in other words, that it is the chief part of their task to tell us, not the 

 actual nature of things, but how they became what they are. The 

 reader who has followed me so far will see for himself the error of this 

 objection. In the first place, ether can never be studied historically, 

 because it had no origin. Anyone who'takes up a manual of physics or 

 chemistry will see that in these it is nearly always a question of what 

 the law is — what is vaUd independently of time — not what has come into 

 being. There are, of course, historical questions in these sciences, but 

 very rarely; their investigations are almost always purely scientific. On 

 the other hand, zoology and botany use both methods. In my contrast 

 of the two methods, I aim merely at a logical appreciation of them; I 

 am not bringing into opposition sciences that diifer according to 

 their material. I merely say that all our sciences may employ both 

 methods, but that one finds the one method more suitable, another the 

 other method. The first method determines what holds good indepen- 

 dently of all time, by discovering the common element in phenomena ; 

 the second determines what has taken place once, regarding, not the 

 common but the individual features, and interpreting it according to 

 the documents. The two methods are, therefore, of a precisely 

 opposite character. 



