LEIBNITZ. 95 



" All the same, if we can imagine a few intelligible and simple 

 principles upon which the stars, and earth, and all the visible 

 world might have been produced (although we well know that 

 it has not been produced in this fashion), we reach a better 

 understanding of the nature of all things than if we describe 

 simply how things now are, or how we believe them to have been, 

 created. Because I believe I have discovered such principles, 

 I shall endeavour to explain them." 



GOTTFRIED WILHELM LEIBNITZ (1646-1716), the 

 first of the great philosophers of Germany, advo- 

 cated two ideas in his writings which exerted a 

 great and widely misleading influence in Biology. 

 The first was his doctrine of Continuity, and the 

 second, his doctrine of Perfectibility in the Monads. 

 The law of Perfectibility is said to have been sug- 

 gested by Bruno, but as applied to the animal 

 creation certainly came more or less directly from 

 Aristotle. It is surprising to find how Leibnitz' 

 principle of Continuity adapted itself to the idea 

 of Evolution of organic beings. In part from obser- 

 vations of his own, and probably in part influenced 

 by Aristotle, Leibnitz expressed the law of Conti- 

 nuity as applied to life as follows : " All natural 

 orders of beings present but a single chain, in which 

 the different classes of animals, like so many rings, 

 are so closely united that it is not possible either 

 by observation or imagination to determine where 

 one ends or begins." 



He was very familiar both with Bacon and 

 Descartes, and by the former had probably had 

 his attention called to the matter of Variation. 



