9 o SCIENTIFIC METHOD IN PHILOSOPHY 



of private spaces (perspectives), or, since " points of 

 view " have not been defined, we may say it is the 

 system of the private spaces themselves. These private 

 spaces will each count as one point, or at any rate as 

 one element, in perspective space. They are ordered by 

 means of their similarities. Suppose, for example, that 

 we start from one which contains the appearance of a 

 circular disc, such as would be called a penny, and suppose 

 this appearance, in the perspective in question, is circular, 

 not elliptic. We can then form a whole series of 

 perspectives containing a graduated series of circular 

 aspects of varying sizes : for this purpose we only have 

 to move (as we say) towards the penny or away from it. 

 The perspectives in which the penny looks circular will 

 be said to lie on a straight line in perspective space, and 

 their order on this line will be that of the sizes of the 

 circular aspects. Moreover though this statement must 

 be noticed and subsequently examined the perspectives in 

 which the penny looks big will be said to be nearer to the 

 penny than those in which it looks small. It is to be re- 

 marked also that any other " thing " than our penny might 

 have been chosen to define the relations of our perspectives 

 in perspective space, and that experience shows that the 

 same spatial order of perspectives would have resulted. 



In order to explain the correlation of private spaces 

 with perspective space, we have first to explain what is 

 meant by " the place (in perspective space) where a thing 

 is." For this purpose, let us again consider the penny 

 which appears in many perspectives. We formed a 

 straight line of perspectives in which the penny looked 

 circular, and we agreed that those in which it looked 

 larger were to be considered as nearer to the penny. We 

 can form another straight line of perspectives in which 

 the penny is seen end-on and looks like a straight line of 



