418 PRINCIPLES OF NATURE AND GRACE 



action is always equal to reaction, and the whole effect 

 is always equivalent to its full cause. And it is remark- 

 able \_surprenant] that by the sole consideration of efficient 

 causes or of matter it was impossible to explain these 

 laws of motion which have been discovered in our time 

 and of which a part has been discovered by myself. 

 For I have found that we must have recourse to final 

 causes, and that these laws are dependent not upon the 

 principle of necessity, like the truths of logic, arithmetic, 

 and geometry, but upon the principle of fitness [con- 

 venance], that is to say, upon the choice of wisdom. And 

 this is one of the most effective and remarkable proofs 

 of the existence of God for those who can go deeply into 

 these things 49 . 



12. Again, it follows from the perfection of the Su- 

 preme Author not only that the order of the whole 

 universe is the most perfect that can be, but also that 

 each living mirror representing the universe according 

 to its point of view, that is to say, each Monad, each 

 substantial centre, must have its perceptions and its 

 desires [appetite] as thoroughly well-ordered as is com- 

 patible with all the rest. Whence it also follows that 

 souls, that is to say, the most dominant Monads, or 

 rather animals themselves 50 cannot fail to awake again 



49 The laws of actual 'concrete' motion cannot be deduced a priori 

 under the law of contradiction ; but a knowledge of them involves 

 a reference to experience. As a result of this reference to experience 

 we are compelled to conceive body, not as mere externality of parts, 

 indifferent to motion, but as something which always has a, force of 

 its own. Thus bodies are ultimately or really (as distinct from 

 phenomenally) independent forces (Monads), which differ from one 

 another endlessly but are yet in such harmony that they form 

 one perfectly regular system, the laws of which we can discover 

 and state. Such a system could never have come into existence 

 'of itself,' by a law of blind necessity, indifferent to good and evil, 

 like the principle of contradiction. An all-wise, all-powerful and 

 infinitely good God must have chosen this system as the best 

 among all possible systems. Cf. Monadology, 51. 



50 E. omits, themselves.' 



