OF THE SPIRIT. 281 



This process was first introduced in the mathematical 

 and dynamical sciences, and in the more or less suc- 

 cessful attempts to reduce other branches of natural 

 science such as acoustics, optics, thermotics, electrics,, 

 chemistry, and biology, to a study of mechanical pro- 

 cesses, which possess merely quantitative (easily measu- 

 rable) in the place of qualitative differences. It went 

 hand in hand, in the region of psychology, with the 

 distinction of primary and secondary qualities : the 

 former, such as size, figure, and resistance being 

 measurable, more permanent and objective, as com- 

 pared with the latter, such as colour, sound, and heat,, 

 which are subjective and difficult to fix. Being ob- 

 jective, i.e., the same or similar to different observers> 

 the former acquire the character of greater reality, 

 whereas they only possess, in the world of our ex- 

 perience, more definiteness, more stability, and more 

 permanence ; they can also be easily reproduced in, 

 diagrams and models and recalled by the powers of 

 memory. All these advantages make them more think- 

 able or intelligible, for they do not disappear so easily out, 

 of our mental field of vision as the sensations of colour, 

 heat, taste, smell, or the numerous and ever-changing 

 inner sensations, such as those of effort and emotion. 



Thus it came about that the so-called primary quali- 



thought." With most persons this 

 breaking up of the original synoptic 

 aspect, the primary self, is carried 

 as far as intersubjective communi- 

 cation with other persons through 

 the aid of language, and the in- 

 terests of life and practical work 

 make it necessary. Science only 

 carries this process a step further 



through what is termed "analysis 

 and synthesis " of ideas, using ideas 

 in the sense of Hume. This 

 process of analysis or synthesis 

 reaches perfection only in the 

 notions of number and space, and 

 in the sciences that work with 

 these notions. 



