VI EVOLUTION IN BIOLOGY 207 



generalement la nature de toutes les choses qui sont au monde si 

 nous pouvons imaginer quelques principes qui soient fort intelli- 

 gibles et fort simples, desquels nous puissionsvoirclairementque 

 les astres et la terre et enfin tout ce monde visible auroit pu etre 

 produit ainsi que de quelques semences (bien que nous sachions 

 qu'il n'a pas ete produit en cette fa^on) que si nous la decrivions 

 seulement comme il est, ou bien comme nous croyons qu'il a ete 

 cree. Et parceque je pense avoir trouve des principes qui sont 

 tels, je tacherai ici de les expliquer." 1 



If we read between the lines of this singular 

 exhibition of force of one kind and weakness of 

 another, it is clear that Descartes believed that he 

 had divined the mode in which the physical uni- 

 verse had been evolved ; and the " Traite de 

 1'Homme," and the essay " Sur les Passions " afford 

 abundant additional evidence that he sought for, 

 and thought he had found, an explanation of the 

 phenomena of physical life by deduction from 

 purely physical laws. 



Spinoza abounds in the same sense, and is as 

 usual perfectly candid 



" Naturae leges et regulse, secundum quas omnia fiunt et ex 

 unis formis in alias mutantur, sunt ubique et semper eadem." 2 



Leibnitz's doctrine of continuity necessarily led 

 him in the same direction ; and, of the infinite 

 multitude of monads with which he peopled the 

 world, each is supposed to be the focus of an end- 

 less process of evolution and involution. In the 



1 Principes de la Philosophic, Troisieme partie, 45. 



2 Ethices, Pars tertia, Prsefatio. 



