OF THE COSMOS. INTRODUCTION. 9 



observation which form the principal basis of present 

 scientific opinion. The order of succession in which these 

 results are presented will again be that which, in confor- 

 mity with previously enounced principles, was followed 

 by me in the general view of Nature. Before, however, pro- 

 ceeding to particular results in the several sciences, I desire 

 still to add a few more general elucidatory considerations. 

 The unexpected favour with which my undertaking has 

 been received, both in my own and in other countries, 

 makes me doubly feel the need of expressing myself once 

 more as distinctly as possible in reference to the fundamen- 

 tal idea of the entire work ; and respecting -requirements 

 which I have never even attempted to fulfil, because, accord- 

 ing to my individual view of our experimental knowledge, 

 their fulfilment could not be contemplated by me. With 

 these considerations, to which I am led by the desire of 

 justifying my manner of proceeding, there are naturally 

 associated historical reminiscences of earlier attempts to 

 discover the idea of the Universe, which should so compre- 

 hend its structure as to reduce all phsenomena, in their 

 causal connection, to a single principle. 



The fundamental principle (7) of my work on the Cosmos, 

 as developed by me more than twenty years ago in lectures 

 delivered in the French and German languages, at Paris 

 and at Berlin, consists in the constant tendency or endea- 

 vour to embrace the phsenomena of the universe as a natural 

 Whole ; to shew how, in particular groups of the phsenomena, 

 those conditions which are common to the entire group, 

 i. e. the government of great and comprehensive laws, have 

 been discovered and recognised, and by what means we 

 ascend from the knowledge of these laws to that of their 



