290 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



Consider space first. At the perceptual level space is a 

 relational feature of events. Space reduces to position. 

 But position is meaningless apart from relations of distance 

 and direction, and these must always lie between events. 

 An event has position because it can be reached from an- 

 other event by a movement through a certain distance and 

 in a certain direction. As an ultimate point of reference 

 one always has his own body, and this tends to give to the 

 "here," as will be seen later, a privileged position. Elim- 

 ination of events from space, as in a perfectly dark room, 

 results in a weakening of one's spatial sense; ascertainment 

 of distance is conspicuously unreliable at sea; and the di- 

 rectional aspects of space easily become confused when one 

 is riding an airplane through a fog. Space, thus, is for the 

 individual a feature or aspect of events — essentially like 

 color or weight, except that it is relational in character. 

 Space must be occupied by events, otherwise it is not 

 space. 



Time exhibits in a more pronounced manner a dependence 

 upon events. Time is, in essence, change, and change is 

 always an aspect of events. For there to be change, some- 

 thing must change. Change, in fact, reduces to three aspects: 

 It involves, first, "the coming in, rise or emergence into 

 existence of something new, something which was not be- 

 fore. Every alteration or development is an illustration: a 

 body moves into a new point; an organism passes into a 

 stage which was hitherto not its own." But this requires a 

 second aspect. "Plainly the new which comes to be does 

 not rise into a void, but into a space already there, into a 

 world already old. Here is the second moment of change — 

 the persistence of a core of reality upon which the new is 

 grafted. This abiding aspect of the changing thing is usu- 

 ally called ' the thing which ' changes. . . . Third and last, 

 change involves disappearance from existence, disintegra- 

 tion, loss. If we did not know this independently, we could 

 deduce it from the moments of change already cited. For 

 the new, by breaking in upon the old situation and giving 



