October 24, 1913] 



SCIENCE 



575 



shall show you in a moment a little evi- 

 dence bearing upon the subject. 



The second of the leading ideas of the 

 Naturphilosophie related to the special 

 form which they conceived the unity of 

 natural truth to take. They were very 

 fond of speculating upon the unity of what 

 we now call the various forms of natural 

 energy. Light, electricity, magnetism, the 

 vital processes, these, they were disposed to 

 insist, were forms or stages of a single, all 

 pervasive natural process. Now, nobody 

 with the least sense for logical connections 

 can for a moment confuse the modern doc- 

 trine of energy, with its exactness of quan- 

 titative definitions and relations, with the 

 vaguely conceived teleological unity that 

 the Naturphilosophen ascribed to the nat- 

 ural world. On the other hand, nobody 

 who considers fairly the history of the 

 topic can fail to see that the modern doc- 

 trine of energy had two very distinct, but 

 marvelously related sources. One of these 

 sources was the state of modern technolog- 

 ical knowledge in the early part of the 

 nineteenth century. The other source is 

 the state of general philosophy in the same 

 period. The modern doctrine of energy is 

 due, I insist, to a curious and unintended 

 alliance between the interests of the engi- 

 neers and the ideas of the philosophers. I 

 shall recur to this topic again very soon. 

 For the rest, one may say that a concep- 

 tion like that of the modern doctrine of 

 energy is not found until one learns to look 

 for it in the right spirit. The Naturphi- 

 losophie had its indirect part in creating 

 this right spirit with which later men, far 

 better equipped than were the Naturphilos- 

 ophen themselves, looked for the truth 

 which took form in the doctrine of energy. 



Thirdly, the Naturphilosophie had an- 

 other leading idea which more directly con- 

 cerns your own science. This was the idea 

 of comprehending organic products by 



conceiving them as results or at any rate 

 as stages, of a process which has the form 

 of an evolution. The more modern evolu- 

 tionary ideas are prefigured in all sorts of 

 vaguer and of more concrete forms by the 

 various Naturphilosophen, from Schelling 

 onwards. Oken comes nearest of all of the 

 group to using categories like those of a 

 modern evolutionist. When, in the gen- 

 eration that was in its early prime in the 

 thirties and the forties, various naturalists 

 made a systematic method of appealing to 

 a study of the embryology, of the early 

 stages, of any natural form, as a principal 

 means of understanding its mature struc- 

 ture, they were following a leading idea 

 which was again in one sense a very an- 

 cient idea, since the Greeks already pos- 

 sessed cruder forms of this idea. But, on 

 the other hand, this leading idea had as- 

 sumed, by the time in question, shapes 

 which it could not have assumed had not 

 the Naturphilosophen preceded. Herein 

 lay, in all probability, one of the most sub- 

 stantial of their indirect influences upon 

 the course of later science. In the minds 

 of the Naturphilosophen, this idea of con- 

 ceiving organic nature as a process to be 

 understood in evolutionary, or at least in 

 quasi-evolutionary ways, was a direct re- 

 sult of their philosophical principles. 

 They not only possesed the idea; but they 

 applied it in ways which brought it into 

 relations with modern science. The pre- 

 dominance of Entwickelungsgeschichte in 

 all the later studies of German science in 

 the nineteenth century is in all probability 

 largely influenced by the indirect effects of 

 the Naturphilosophie. 



As you see, no one of the three leading 

 ideas just mentioned can be regarded as 

 originated by the Naturphilosophie. Each 

 is, in some sense and in some degree, a very 

 old idea. But the interest of the Natur- 

 philosophie lies in the fact that just be- 



