200 



SCIENTIFIC THOUGHT. 



Mliller. And out of the circle of which E. H. Weber 

 was the centre, has emanated that work of Fechner, 

 'Elements of Psycho-physics/ which marks an epoch 

 in psychology : it is indeed mainly occupied with the ex- 

 position and application of what is termed Weber's law 

 of sensation. 1 In the course of the second quarter of the 

 century, the names of Gauss and Jacobi in mathematics, 

 of Liebig and Wohler in chemistry, of Schleiden and 

 Schwann in the science of life, of Miiller and Weber in 

 physiology, raised German science to the level previ- 

 ously reached by the French Academicians, by Laplace 

 and Lagrange, by Lavoisier and Berthollet, by Cuvier 

 and St - Hilaire, by Vicq - d'Azyr and Bichat. During 



created by the posthumous publi- 

 cation of Riemann's celebrated Me- 

 moir, 'Ueber die Hypothesen welche 

 der Geometric zu Grunde liegen,' 

 Gottingen, 1865. Helmholtz's in- 

 vention of the ophthalmoscope in 

 1851 marks an epoch in ophthalmo- 



!ogy- 



1 Gustav Theodor Fechner (1806- 

 87), professor at the University of 

 Leipsic, was an extraordinary man. 

 The wide range of his interests and 

 his great personal influence are well 

 described in his biography by Dr 

 Kuntze, ' G. T. Fechner, Bin 

 deutsches Gelehrtenleben,' Leipzig, 

 1892. Together with Lotze he may 

 be said to have brought about the 

 reform of German speculative phil- 

 osophy, and in relation to this he 

 will occupy our attention largely 

 in a later portion of this book. He 

 belonged to the circle of which E. 

 H. Weber was the centre, and has 

 taken an important place in the 

 history of philosophy and science 

 by his now celebrated work, ' Ele- 

 mente der Psychophysik,' 2 vols., 

 Leipzig. 1860; 2d ed., 1890. The 



object of this work is to establish 

 " an exact doctrine of the relations 

 of body and mind," the principal 

 task being " to fix the measure of 

 psychical quantities." He says in 

 the preface : " The empirical law 

 which forms the principal founda- 

 tion, was laid down long ago 

 by different students in different 

 branches, and was expressed with 

 comparative generality mainly by 

 E. H. Weber, whom I would 

 call the father of psycho-physics " 

 (Preface, p. v). In early life 

 Fechner did much, by his transla- 

 tions of Biot's ' Physics ' and The'- 

 nard's ' Chemistry,' as well as by his 

 own experimental works, to intro- 

 duce the French scientific spirit into 

 German research. His psycho-phy- 

 sical labours have been continued 

 by Prof. Wundt ; his importance 

 as marking a turning - point in 

 German philosophy is brought out 

 in Paulsen's ' Einleitung in die 

 Philosophic,' Berlin, 1890. See 

 especially Preface, p. viii, and p. 

 318, where Fechner is placed before 

 Lotze. 



