220 THE MONADOLOGY 



neither substance nor accident can come into a Monad 

 from outside 11 . 



8. Yet the Monads must have some qualities, otherwise 

 they would not even be existing things 12 . And if simple 

 substances did not differ in quality, there would be 



is a considerable variety of more or less vague opinion as to the 

 nature of the relation. Leibniz is evidently thinking of a theory 

 (not that of Thomas Aquinas), according to which sense-perception 

 means that particles are detached from the body perceived and 

 pass into the percipient, in whom they are reconstructed into 

 images or representations of qualities in the thing perceived. 

 Images of this kind were called efScwAa by Democritus. Of. Ritter 

 and Preller, Historia Philosophies Graecae, 155. Atomists felt bound 

 to explain the action of body upon soul by the suggestion of some 

 kind of influxus physicus. Descartes has a parallel passage to this 

 of Leibniz, in which he says that he ' desires to rid people's minds 

 of all these little images, flying through the air, called intentional 

 species, which give s'o much work to the imagination of philo- 

 sophers.' Dioptrique, Discours I. Cf. ether passages quoted by Veitch 

 in his Translation of Descartes' s Method and Meditations, note 2 l Idea.' 



u Kant pointed out that a thing may have < intensive' as well 

 as * extensive ' quantity, i. e. quantity which is not divisible into 

 spatial parts as well as quantity which is so divisible. A stone 

 descending from a height loses a certain * intensive quantity ' 

 without losing any of its spatial parts. And thus a simple sub- 

 stance may, in a certain sense, lose and receive quality. Cf. 

 Critique of Pure Reason (Hartenstein, ii. 178 ; Rosenkranz, ii. 145 ; 

 Meiklejohn's Tr., p. 125), Kant argues that the simplicity of the 

 soul (i.e. the absence of parts in it) does not necessarily prove its 

 indestructibility, for, though it has no parts, it may lose con- 

 sciousness and the rest of its essential qualities (Hartenstein, ii. 

 318; Rosenkranz, ii. 792; Meiklejohn's Tr., p. 245). Compare 

 Kant's 'intensive quantity' with Leibniz's degrees of Perception 

 and Appetition. 



12 After this sentence Leibniz originally wrote, and then deleted, 

 these words : ' And if simple substances were nonentities [news], 

 compounds also would be reduced to nothing.' This emphasizes 

 the point that a being without quality is indistinguishable from 

 nothing ; cf. Hegel's Logic, Wallace's Tr., pp. 158 sqq. Quantity 

 always presupposes quality ; see Introduction, Part ii. pp. 27 sqq. 

 Leibniz seems also to imply that each Monad must have more 

 than one quality. On the other hand, Herbart (1776-1841), whose 

 Monadology owes much to that of Leibniz, and who calls his 

 Monads ' primary qualities ' (Urqualitaten'), holds that a substance 

 cannot be perfectly simple unless it has only one ultimate quality. 



