COSMIC PHILOSOPHY 



Again, other things equal, phenomena that 

 are frequent have . been scientifically explained 

 sooner than unusual phenomena. " Rainbows 

 and comets do not differ greatly in conspicu- 

 ousness, and a rainbow is intrinsically the more 

 involved phenomenon ; but chiefly because of 

 their far greater commonness, rainbows were per- 

 ceived to have a direct dependence on sun and 

 rain while yet comets were regarded as super- 

 natural appearances." 



In like manner the more concrete relations 

 have been formulated before those that are more 

 abstract. If we were to adhere rigorously to 

 Comte's principle of decreasing generality, we 

 should have to place the infinitesimal calcu- 

 lus before algebra, and algebra before arith- 

 metic. But the order of development has been 

 just the reverse, — from arithmetic, the least 

 abstract department, to calculus, the most ab- 

 stract. 



Lastly I would suggest a circumstance, not 

 mentioned by Mr. Spencer, namely that, other 

 things equal, the sciences must advance accord- 

 ing to the ratio between the complexity of the 

 phenomena with which they deal and the mul- 

 tiplicity of our means for investigating those 

 phenomena. I shall presently describe our three 

 chief implements for extorting the secrets of 

 Nature — observation, experiment, and com- 

 parison ; showing that in general, as pheno- 



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