136 INTRODUCTION 



stance is to perceive, represent, or express every other, we 

 seem to have come upon the doctrine of the relativity of 

 human knowledge in its worst form. It seems as if 

 knowledge must be compared to the life of those unhappy 

 islanders * who earn a precarious livelihood by taking in 

 one another's washing.' 



As to the meaning of the terms, Leibniz says that l one 

 thing expresses another (in my sense) when there is 

 a constant and regular [regie] relation between what can 

 be said of the one and what can be said of the other. It 

 is thus that a projection in perspective expresses the 

 original figure V Any two things, then, are related to 

 one another as perceiver and perceived, when the predi- 

 cates or qualities of the one (whatever these predicates or 

 qualities may be) always vary concomitantly with the 

 predicates or qualities of the other. Perception, repre- 

 sentation, or expression is then a relation of harmony (or 

 development according to some law or principle) between 

 the qualities of individual substances. But these qualities 

 are themselves perceptions. What, then, is the ultimate 

 reality of which they are all representations ? Leibniz's 

 answer is that the ultimate reality is the nature of God or 

 the ideas of God as an intuitive Knower. God alone has 

 a knowledge which is entirely adequate, perfectly realized ; 

 in Him the universe is transparent through and through. 

 There is no reality beyond thought, to which thought 

 must correspond. Thought cannot in any way represent 

 that which is entirely other than itself, that which is 

 separated from it ' by the whole diameter of being ' (or by 

 an even greater distance if that were possible). For no 

 sign can be entirely cut off from the thing signified. Sign 

 and thing signified must have some ground of unity in 

 virtue of which this relation between them is possible. 



1 Lettre a Arnauld (1687) (G. ii. 112) : 'Expression is common to 

 all soul-principles [formes]. It is a genus, oT which natural pt-r- 

 _cPt ion animal feeling and intellectual knowledge are species.' 

 Cf. tnis Introduction, Part iii. p. 112, note 3. 



