INTRODUCTORY. 5 1 



natural science and the positivist philosophy, the word 

 Evolution has been introduced by Herbert Spencer to 

 denote that form of development which is based upon 

 mechanical or physical principles. 



All through the present section of this History the 

 idea of development in these two distinct forms will be 

 shown to have influenced philosophical thought and given 

 to philosophical problems an entirely altered complexion. 

 It has, moreover, tended latterly to bring together scien- 

 tific and philosophical thought, rendering, as it appears, 

 the former more philosophical and the latter more 

 scientific. The two aspects which the idea of develop- 42. 

 ment has assumed centre respectively in the philosophies spe g nce a r n 

 of Hegel and of Herbert Spencer. 



There exist for our human mind only two intelligible 

 forms of spontaneous, that is, inevitable and never-ceasing, 

 change namely, physical motion on the one side and x 

 the movement of thought on the other. Neither can be 

 arrested or annihilated : they form the simplest examples, 

 which cannot be further analysed, of the process of 

 development, and they underlie respectively the systems 

 of Herbert Spencer and of Hegel. 1 



1 Before the modern concep- 

 tions of Evolution were distinctly 

 formulated, this view was pro- 

 minently brought forward in a 

 criticism of Hegel's as well as of 

 Herbart's system, by Adolf Tren- 

 delenburg in his ' Logische Unter- 



second edition (1862) we find the 

 following remarkable passage : 

 "The prejudice of the Germans 

 must be abandoned that for the 

 philosophy of the future a new 

 principle had to be discovered. The 

 principle has been found ; it lies in 



suchungen,' of which the first | that organic conception of the Uni- 



edition appeared in 1840. It marks j verse which has its foundation in 



at the same time a reversion to j Plato and Aristotle, and which, 



Platonic and Aristotelian ideas, to j continuing from them, will have to 



that era of Thought when science complete itself in a profounder ex- 



and philosophy were not yet 

 divided. In the Preface to the 



animation of fundamental ideas and 

 through an interchange with the 



