METHODS OF PHYSIOLOGICAL RESEARCH 21 



problems and the goal of science, he regarded critically the special 

 methods and questions only as means to an end, as means for arriv- 

 ing at a harmonious comprehension of nature. Throughout his 

 whole life he remained steadily true to this philosophical concep- 

 tion of science, which he had set forth with energy in his inaugural 

 address, " Von dem Bedurfniss der Physiologie nach einer philoso- 

 phischen Naturhetrachhmg." It is remarkable that, notwithstand- 

 ing the unalloyed admiration aroused by the figure of Mtiller, the 

 later phj-siology has often wholly neglected this element. This is 

 particularly noticeable in two fields in which from his youth up he 

 took the most active interest, — that oi psychology, and that of com- 

 porative physiology. 



Psychology is avoided by the physiology of to-day almost with 

 fear, an attitude that is in peculiar contrast with that of Mtiller. He 

 regarded physiology as essential to advance in psychology by 

 empirical methods, and in his examination for the doctorate he 

 defended the thesis, " Psychologies nemo nisi physiologus." Un- 

 doubtedly, the science of psychology ought not to be considered as 

 simply a part of physiolog}-. But the achievements of physiology 

 in the field of the nervous system and the sense-organs are of so 

 fundamental significance for psychology, that it may be said that 

 the former science is more nearly related than any other to the 

 latter. Miiller's own labours show very clearly with what success 

 physiology is capable of handling psychological problems, for 

 scarcely any physiological discovery has a more important bearing 

 upon all psychology and the theory of knowledge — although un- 

 fortunately it is not generally appreciated — than the doctrine of 

 the specific energy of the nerves or organs of the special senses. 

 This doctrine afiirms that different stimuli of whatever kind, when 

 applied to the same sense-organ, e.g. the eye, are capable of calling 

 forth only one and the same kind of sensation, namely, that sensa- 

 tion that is mediated by the sense-organ in question under the 

 influence of its natural stimulus, in the case of the eye, light. Vice 

 versa, one and the same stimulus, when applied to different sense- 

 organs, calls forth entirely different sensations according to the 

 nature of the organ upon which it works. This doctrine is 

 founded upon two fundamental facts : first, that in reality the 

 external world is not what it appears to us to be when perceived 

 through the spectacles of our sense-organs ; and, second, that by 

 the path of our sense-organs we cannot arrive at an adequate 

 knowledge of the world. Besides this fundamental proposition, 

 however, Mtiller discovered many other important psychological 

 facts, which he has presented in his works ; " Zur verglcichenden 

 Physiologie des Gesichtssinnes des Menschcn unci der Thiere," " Ueber 

 (He phantastischen Gesichtserscheinungen," and the section " Vom 

 Seelenleben " in his " Handhuch der Physiologie des Menschcn.'' 



Miiller's teacher Rudolphi had said : " Comparative anatomy is 



