10 THE MEANING OF EVOLUTION 



pressure of what he called a perfecting principle. Out 

 of the inanimate rocks had sprung the marine plants 

 the seaweeds. From these had developed first 

 "plant animals" like the sea anemones and the sponges. 

 These grew attached to the rocks, as plants do. With 

 higher development came locomotion, with ever-in- 

 creasing energy. At last man arose, the crown of all 

 creation. Presiding over all this advance is the "effi- 

 cient cause," God. Aristotle rejected entirely the ear- 

 lier ideas that any of this work came about by chance. 

 He was certain of the existence of plan and purpose 

 in the development. 



Just a little before the time of Christ the Latin 

 poet, Lucretius, wrote a poem on "The Nature of 

 Things." Here he describes how in the early years 

 the beginnings of things in small, disjointed fashion 

 moved about among each other at first in utter con- 

 fusion, each trying itself with the other. After many 

 trials the proper members came together. When they 

 had been thus placed the warmth of the sun shining 

 down upon the earth helped the earth to reproduce 

 the same sort of creatures. So living things came 

 up and flourished. The poem expresses many beauti- 

 ful ideas, but the underlying conceptions lack the unity 

 and grandeur that marked Aristotle's work, which 

 later was the potent influence in shaping men's minds. 

 It died out after a while, only to awake in the Re- 



