OF KNOWLEDGE. 



403 



whatever, and have no right to be called knowledge, 

 however exact they may be. A recognition of these ei. 



Limitation 



fundamental truths, and of the real nature of scientific of scientific 



knowledge. 



knowledge, is gradually making its way into philosophical 

 literature. It is also more and more being allowed by 

 the leaders of scientific thought themselves, some of 

 whom have probably done more than philosophers by 

 profession to lay bare the roots and foundations of 

 scientific reasoning. At best it has been, and is still, 

 a slow process by which these plain truths are being 

 elaborated and promulgated, nor is it possible to give 

 any single names with which we could identify in any- 

 thing like completeness the modern theory of knowledge. 

 In a note * I have tried to collect references to the more 



1 The most important enuncia- 

 tion of the nature of exact science, 

 viz. , that it aims at describing and 

 not at explaining natural pheno- 

 mena, is probably to be found in 

 the introductory sentence of G. 

 Kirchhoff's Lectures ' On Dynamics.' 

 On the idea expressed in this 

 simple sentence the whole of the 

 purely scientific discussion of the 

 principles of natural philosophy 

 hangs, together with the more 

 recent interest taken by philosophi- 

 cal writers in this subject. The 

 sentence has been quoted over and 

 over again, not only in text-books 

 of natural philosophy but also in 

 philosophical treatises. It is, on 

 the one side, the result of the 

 labours of mathematicians and ex- 

 perimentalists, on the other side 

 the starting - point for a clearer 

 separation and recognition of the 

 different aims of scientific and 

 philosophical thought. Among 

 German thinkers it is especially 

 E. du Bois Reymond who, in many 

 passages of his various Addresses, 



has referred to this subject. Shortly 

 before Kirchhoff's Lectures there 

 appeared E. Duhring's ' Critical 

 History of the general Principles 

 of Mechanics' (1873), a book which 

 would have exercised a greater 

 influence had it not been for the 

 polemical invectives introduced in- 

 to the later editions. Kirchhoff s 

 definition should be contrasted 

 with the closing sentence of Lotze's 

 'Logic' (1874), in which he ex- 

 presses the hope that "German 

 philosophy will always rise again 

 to the attempt to comprehend and 

 not only to calculate the order of 

 things." The next important and 

 epoch - making discussion of this 

 subject is the ' Critical Exposition 

 of{ the Development of Dynamics,' 

 by E. Mach ( ' Die Mechanik in 

 ihrer Entwicklung,' 1st ed., 1883), 

 a book which has now acquired 

 a world-wide reputation, and should 

 be studied by every teacher of 

 natural as well as of mental philo- 

 sophy. Somewhat later, Karl 

 Pearson published his 'Grammar 



