i 



EVOLUTION BEFORE DARWIN 31 



shape. The lowest animals are nothing else; all the 

 others are mere aggregations of such vesicles. 



Other philosophers had already pointed out the 

 variable character of every living organism. In 

 1802, Treviranus had published a book on the sub- 

 ject. But those theories were shrouded in nebulous 

 speculations and led to absurd conclusions; this was 

 inevitable, considering the method adopted by that 

 school of philosophers: instead of starting from 

 facts observed and then working their way towards 

 theoretical generalisations, they started from abstract 

 conceptions and came to the conclusion that the phys- 

 ical world corresponded to their conceptions. 



Suclf methods, contrary to the spirit of natural 

 science, could not inspire any confidence; this is why 

 the transmutation idea, misrepresented by those phi- 

 losophers, was rejected by scientists. There was_ac- / 

 tually a reaction against all general ideas and the f ol- fs 

 lowing period, from 1830, the date of the famous 

 debate between Cuvier and Geoffroi Saint-Hilaire, 

 unti&.the publication of Darwin's book, was charac- 

 terised by its materialistic spirit, and its indifference 

 to philosophical research. 



There were exceptions, however, notable exceptions. 

 In 1830, Lyell published his "Principles of Geol- 

 ogy/' which paved the way for the application of 

 evolutionary ideas to that science. The author re- 

 belled against Cuvier's theory of catastrophes and 



