246 DARWIN. 



Retrospect. 



Now that we have brought together the evi- 

 dences, our difficulty lies in choosing the via media 

 between an overestimate and an underestimate of 

 actual continuity. 



From the ' formless masses ' of the thought of 

 Empedocles we have traced Evolution to its per- 

 fect expression by Darwin. The metaphysical en- 

 vironment of the idea has been seen shaping itself 

 in the better understanding of the relations of Causa- 

 tion, Design, and Creation, while the natural en- 

 vironment has been seen expanding with the 

 biological sciences. Two of Aristotle's principles, 

 midway between physics and metaphysics, seem to 

 have exerted a great and often misleading influence. 

 I refer first to his ' perfecting tendency ' which led 

 Leibnitz and all his naturalist and speculative 

 followers away from the search for a natural cause 

 of Adaptation ; and second, his ' unity of type,' 

 which, as finally developed in the mind of St. Hilaire 

 and Owen, proved to be a compromise between 

 Special Creation and Evolution. 



The idea of Evolution, rooted in the cosmic evo- 

 lution and ' movement ' of Heraclitus and Aristotle, 

 has passed to the progressive development and 

 succession of life seen in Empedocles, Aristotle, 

 Bruno, Descartes, Goethe, and in the more concrete 



