i6o MYSTICISM AND LOGIC 



described as the space of points of view, since each 

 private world may be regarded as the appearance 

 which the universe presents from a certain point of 

 view. I prefer, however, to speak of it as the space of 

 perspectives, in order to obviate the suggestion that a 

 private world is only real when someone views it. 

 And for the same reason, when I wish to speak of a 

 private world without assuming a percipient, I shall call 

 it a " perspective." 



We have now to explain how the different perspectives 

 are ordered in one space. This is effected by means of the 

 correlated " sensibilia " which are regarded as the appear- 

 ances, in different perspectives, of one and the same thing. 

 By moving, and by testimony, we discover that two 

 different perspectives, though they cannot both contain 

 the same "sensibilia," may nevertheless contain very 

 similar ones ; and the spatial order of a certain group of 

 " sensibilia " in a private space of one perspective is 

 found to be identical with, or very similar to, the spatial 

 order of the correlated " sensibilia " in the private space 

 of another perspective. In this way one " sensibile " in 

 one perspective is correlated with one " sensibile " in 

 another. Such correlated " sensibilia " will be called 

 " appearances of one thing." In Leibniz's monadology, 

 since each monad mirrored the whole universe, there was 

 in each perspective a " sensibile " which was an appear- 

 ance of each thing. In our system of perspectives, we 

 make no such assumption of completeness. A given 

 thing will have appearances in some perspectives, but 

 presumably not in certain others. The " thing " being 

 denned as the class of its appearances, if K is the class of 

 perspectives in which a certain thing appears, then is 

 a member of the multiplicative class of K , K being a class 

 of mutually exclusive classes of " sensibilia." And 



