October 24, 1913] 



SCIENCE 



669 



my task is, it is not wholly hopeless. Per- 

 haps, after all, before I am done I may 

 show you a few facts in which as students 

 of the methods and of the general rela- 

 tions of your own science, you may find 

 something that will be serviceable. 



My plan will be this : First I shall sketch 

 for you in the barest outline the external 

 history of the movement called in Germany 

 the NatiirphilosopJiie — its rise, its brief 

 success, its inglorious downfall and end. 

 I shall lay stress, of course, on its relations 

 to natural science, such as they were. 

 Then, secondly, I shall try to indicate to 

 you what the deeper ideas were which lay 

 behind and beneath all the vanities and the 

 excesses of the NaturpJiilosophen. Thirdly, 

 I shall try to indicate how these deeper 

 ideas, despite the vanishing of the Natur- 

 philosophie from the scene, indirectly but 

 seriously influenced the course of the later 

 development of natural science in the nine- 

 teenth century, and how these ideas seem to 

 be traceable even in some aspects of the 

 history of your own science, so far as those 

 aspects are visible to the layman.. Fourthly, 

 and lastly, I shall present to you the ques- 

 tion whether some light is not thrown upon 

 the logic of natural science, upon the ideals 

 and methods of scientific work, by con- 

 sidering the relation between those deeper 

 ideas that inspired the Naturphilosophie 

 and the actual growth of scientific investi- 

 gation in the years since 1840. 



First then, for the purely external, and 

 the least interesting aspect of our story. 



At the opening of the nineteenth cen- 

 tury, a very notable philosophical move- 

 ment was under way in the thought of 

 Germany. This movement had been initi- 

 ated, in the years about and after 1780, by 

 ELant — himself a man of considerable 

 training in the physical sciences of his 



time, of considerable acquaintance also with 

 the empirical study of human nature, and 

 of a very sane, sober and critical judgment. 

 Kant intended, amongst other things, to 

 define and to formulate a philosophy of the 

 principles and methods of the natural 

 sciences. He succeeded so well that his 

 ideas are still of great importance for any 

 serious student of logic and of the theory 

 of knowledge; and their value for such a 

 student will not soon be exhausted. 



But Kant's influence was not confined to 

 the study of the foundations and methods 

 of science. He still more immediately influ- 

 enced his time with regard to questions of 

 ethics, of theology, and of the more funda- 

 mental religious issues of life generally. 

 As a fact, his age — which soon became the 

 age of the French Revolution, and of the 

 great classical literature of Germany, was; 

 in his country an age of the humanities, 

 rather than of the natural sciences. His 

 influence was therefore felt, at the moment,, 

 much more in the direction of the human- 

 ities, than in any other way. The philo- 

 sophical movement to which he gave rise, 

 accordingly, soon grew beyond what he had 

 intended, and concerned itself with a con- 

 structive creation of idealistic systems of 

 thought such as he himself considered un- 

 justifiable. And in these systems, about 

 and after the year 1800, the principal 

 stress was laid upon what were essentially 

 ethical and theological issues. The post- 

 Kantian idealists conceived their philos- 

 ophy as a sort of substitute for all that 

 traditional religion had so far meant for 

 the world, or at least as a discovery of the 

 absolute rational warrant for new and 

 higher stages of the religious consciousness. 

 So a great part of their work had no direct 

 relation to the business of natural science. 



It came to pass, however, just before 

 1800, that one of the most enthusiastic of 

 these young idealists, namely, Friedrich 



