THE MONADOLOGY 223 



ii. It follows from what has just been said, that the 

 natural 17 changes of the Monads come from an internal 

 principle, since an external cause can have no influence 

 upon their inner being. (Theod. 396, 400.) 



1 2 18 . But, besides the principle of the change, there 

 must be a particular series of changes [un detail de ce qui 

 change], which constitutes, so to speak, the specific nature 

 and variety of the simple substances. 



13. This particular series of changes should involve a 

 multiplicity in the unit [unite] or in that which is simple. 

 For, as every natural change takes place gradually, 

 something changes and something remains unchanged 19 ; 

 and consequently a simple substance must be affected and 

 related in many ways, although it has no parts 20 . 



17 i. e. other than miraculous changes or than such change as may 

 be implied in the creation or annihilation of a Monad. 



18 At the beginning of 12 Leibniz originally wrote : 'And gener- 

 ally it may be said that force is nothing but the principle of the 

 change.' He seems afterwards to have felt that force was not a deep 

 enough notion to be an adequate expression of the principle which, 

 in 14 and 15, he describes under the names of Perception and 

 Appetition. 



19 The Law of Continuity. Everything is continually changing, 

 and in every part of this change there is both a permanent and a 

 varying element. That is to say, at any moment everything both 

 'is' and 'is not,' everything is becoming something else some- 

 thing which is, nevertheless, not entirely ' other.' 



ao In illustration of this and the following sections, cf. Eeponse aux 

 Reflexions de Bayle (1702) (E. 186 b ; G. iv. 562) : The state of the 

 soul, as of the atom, is a state of change, a tendency. The atom 

 tends to change its place, the soul to change its thought : each 

 changes of itself in the simplest and most uniform way, that its 

 state allows. Whence comes it, then (I shall be asked), that there 

 is so much simplicity in the change of the atom ' [which is taken 

 as being always motion in a straight line at a uniform speed] ' and 

 so much variety in the changes of the soul ? The reason is that the 

 atom (as it is supposed to be, for there is no such thing in nature), 

 although it has parts, has nothing which causes any variety in its 

 tendency, because it is supposed that these parts do not change 

 their relations ; while on the other hand the soul, though it is 

 perfectly indivisible, has a composite tendency, that is to say, it 

 contains a multitude of present thoughts, of which each tends to 



