84 THE EVOLUTION OF MAN. 



of Wolffs Theory of Evolution, and was ignored for half a 

 century. Even Oken and Goethe, the German natural 

 philosophers, who were simultaneously employed in similar 

 speculations, do not appear to have been aware of Lamarck's 

 work. Had they kno\Yn it, it would have been a great 

 help to them, and they would have worked out the Theory 

 of Evolution to a point beyond that which was otherwise 

 possible to them. 



To enable my readers to judge of the great value of the 

 Philosophie Zoologique, I shall here briefly mention some of 

 the most important of Lamarck's ideas. According to him. 

 there is no essential difference between animate and inani- 

 mate nature ; all nature is a single world of connected 

 phenomena, and the same causes which form and trans- 

 form inanimate natural bodies are alone those which are at 

 work in animate nature. Hence, we must apply the same 

 methods of investigation and explanation to both. Life is 

 only a physical phenomenon. The conditions of internal 

 and external form of all organisms — plants and animals, 

 with man at their head — are to be explained, like those of 

 minerals and other inanimate natural bodies, only by 

 natural causes (causce ejfficientes), without the addition of 

 purposive causes (causce finales). The same is true of the 

 origin of the various species. Without contradicting nature, 

 vve can neither assume for them one original act of crea- 

 tion, nor repeated new creations as implied in Cuvier's 

 Doctrine of Catastrophes, — but only a natural, uninterrupted, 

 and necessary evolution. The entire course of the evolu- 

 tion of the earth and its inhabitants is continuous and 

 connected. All the various species of animals and plants 

 which we now see around us, or which ever existed, have 



