246 DAR WIN. 



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 



