DESCRIPTIVE TECHNIQUES 109 



mediary events are called records in the case of historical 

 objects, and messages in the case of spatially remote objects. 

 Both records and messages may be defined as appearances 

 of their respective end-objects at certain points in a physi- 

 cal medium — in the one case the medium being essentially 

 temporal in character, and in the other essentially spatial. 

 If the transmission of messages always requires time, as 

 the theory of the maximum velocity of light requires, and 

 if historical records are simply more or less permanent 

 impressions of messages from past objects, it follows that 

 there is no essential difference between messages and records. 

 They are both appearances of their end-objects. Hence 

 there will be no significant difference between historical 

 documents, verbal reports, and scratches on rocks, on the 

 one hand, and telescopes, spectroscopes, and photometric 

 devices, on the other. In both cases one has something 

 which is given directly, viz., written and spoken words, 

 marks, light images and light bands, on the basis of which, 

 knowing the character of the recording device, he infers the 

 corresponding end-objects, e.g., the Golden Age of Greece, 

 the North American glacier, the moons of Jupiter, and 

 helium in the sun. The fact that a human being is simply a 

 somewhat complex recording instrument has been greatly 

 emphasized in recent behavioristic psychology. It has im- 

 plications to be referred to later in the chapter. 



CONTROL OF PHYSICAL MEDIUM 



Modifications in the physical medium, i.e., in the P- 

 operators, serve to multiply the appearances of the end- 

 object. Since the object is, in its broadest sense, the totality 

 of actual and potential appearances, modifications in the 

 physical medium are techniques for disclosing more and 

 more of the object. The end-object itself, in fact, is simply 

 those of the total appearances which are observed under 

 so-called "normal" conditions of perception. Those appear- 

 ances which constitute the end-object itself are selected, as 

 was suggested in the preceding chapter, by designating, 



