408 PRINCIPLES OF NATURE AND GRACE 



which, although it is perfectly simple, there is an infinite 

 number of angles formed by the lines which meet in it. 



3. All nature is a plenum. There are simple substances 

 everywhere 7 , which are actually separated from one 

 another by activities of their own 8 , and which continually 

 change their relations ; and each specially important 

 [distmguee] !1 simple substance or Monad, which forms the 

 centre of a compound substance (e. g. of an animal) and 

 the principle of its oneness, is surrounded by a mass 

 composed of an infinity of other Monads, which constitute 

 the particular body of this central Monad, and according 

 to the affections of its body 10 the Monad represents, as in 

 a kind of centre, the things which are outside of it. This 

 body is organic, though it forms a kind of automaton or 



time perceptions of the actual parts, and even each part has more 

 than one modification ; and there is perception at the same time 

 not only of each modification, but also of each part. These multi- 

 plied perceptions are different from one another, although our 

 attention cannot always distinguish them, and thus we have 

 confused perceptions, an infinity of which is contained in each 

 distinct perception, because of its relation to everything which is 

 outside. In short, that which is combination of parts in the out- 

 side world is represented in the Monad only by combination of its 

 modifications ; and without this simple beings could not be 

 internally distinguished from one another, and they would have 

 no relation whatever to external things ; and in short, as there 

 are everywhere only simple substances, of which compounds are 

 merely the aggregates, there would be no variation or diversity in 

 things, if there were no internal variation or diversity in simple 

 substances.' Lettre a Masson (1716) (G-. vL 628). Cf. Monadology, 

 notes 12 and 20. 



7 E. omits partout, ' everywhere.' 



8 The idea is that each Monad is separated from every other 

 inasmuch as it has spontaneity, i. e. an activity entirely its own ; for 

 if it had merely an activity like motion, which passes from one 

 thing to another indifferently, it would be united with all other 

 Monads in a continuum and would thus cease to be a real, indepen- 

 dent unit. 



9 E. omits distinguee, reading ' each simple substance.' 



10 Of course, this does not mean that the Monads constituting 

 the body are really affected by outside things. Leibniz is here using 

 popular language. . 



