The Evolution of the Sciences 



against the existence of so great a number of 

 irreducible elements. We have a confused feel- 

 ing that this complexity must hide a simpler 

 truth. However, we no longer believe, like the 

 men of the eighteenth century, that true laws are 

 necessarily simple. We have too many proofs 

 of the complexity of Nature, and we think we 

 know that this complexity is produced, not by 

 the juxtaposition, but by the combination of a 

 small number of elements. In this manner 

 organic chemistry is being constructed out of 

 only four elements, and the complicated motions 

 of the stars obey the single law of universal 

 gravitation. This is doubtlessly why the 

 hypothesis of a single primordial matter lurks in 

 the depths of so many minds; at the slightest 

 occasion it bursts out like a smouldering fire. 

 The following are two topical examples. 



In 1815 the English chemist, Prout, expressed 

 the view that the atomic weights of all elements 

 must be multiples of the atomic weight of 

 hydrogen. This assertion, unsupported by 

 proof, had been forgotten when, thirty years 

 later, Jean-Baptiste Dumas, the great chemist, 

 who was able to take such broad and philo- 



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