tiOi PHILOSOPHICAL THOUGHT. 



stance, cause, life, &c., which lend themselves only with 

 difficulty to any rigid definition at all. The same is also 

 the case with the terms of the more recent vocabulary in- 

 troduced by the theory of descent, such as : selection, the 

 survival of the fittest, the struggle for existence, and lastly, 

 evolution. No thinker has done more to show how all 

 these notions, with their various expressions in scientific 

 and popular language, are ultimately derived from sub- 

 42. jective states, than Professor Ernst Mach of Vienna. 



Mach on the '' 



of"lJi^chani- ^^^ views are independently represented in this country 

 cai physics. -^^ pj,^^^ j^^^^j Pcarson. The matter cannot be more 



clearly put than was done by the former thinker in the 

 following passage taken from his ' Science of Mechanics.' ^ 

 " The division of labour, the restriction of individual 

 inquirers to limited provinces, the investigation of those 

 provinces as a life-work, are the fundamental conditions 

 of a fruitful development of science. Only by such 

 specialisation and restriction of work can the economical 

 instruments of thought, requisite for the mastery of a 

 special field, be perfected. But just here lies a danger 

 — the danger of our overestimating the instruments with 

 which we are so constantly employed, or even of regard- 

 ing them as the objective aim of science. Now, such 

 a state of affairs has, in our opinion, actually been pro- 

 duced by the disproportionate formal development of 

 physics. The majority of natural inquirers ascribe to 

 the intellectual implements of physics, to the concepts, 

 mass, force, atom, and so forth, whose sole office is to 

 revive economically arranged experiences, a reality be- 

 yond and independent of thought. Not only so, but it 



* 'Die Principien der Mechanik,' 1st. ed., 1883, p. 476 sqq. 



