DESCRIPTIVE TECHNIQUES 125 



a reading on a thermometer tells one that the day is hot. 

 It is a common experience that one may observe as present 

 in a situation elements which have been suggested in advance 

 as likely to be present, or elements which the observer 

 would prefer to have present, or even elements which he 

 would prefer not to have present. In all of these cases the 

 ascertainment of the strictly given is quite impossible, for 

 the inferred objects are fused with it or substituted for it, 

 and no act of attention is able to single it out. 



This inferential act is precisely that to which reference 

 was made in the preceding chapter in connection with the 

 discussion of perception. It was suggested at that point 

 that one's concern is not always with the immediately 

 given but with the appearances of the end-object in other 

 contexts. Such information can be gained only through an 

 inferential act. Now there is no danger in this inferential 

 act provided it is recognized as present and, consequently, 

 as a possible source of error. One of the essential tasks of 

 science, in fact, is the making and justifying of precisely 

 such inferences. But when the inferences are unconscious 

 they are important sources of error, for one supposes to 

 be immediately given something which is only inferentially 

 present. This results in a confusion of contextual realms, 

 and hence in an erroneous conception of the part which 

 P-, B-, and Af -operators play in the determination of ap- 

 pearances. So long as the inference is conscious, justifica- 

 tion is sought for it in the knowledge of the laws of operators ; 

 so long as it is unconscious, it enters as a 'disturbing" 

 factor and becomes an important source of error. 



The outcome of these physical, physiological, and psy- 

 chological considerations is the recognition that the task 

 of getting and increasing data is one of great difficulty. 

 In addition to the problem of controlling the object itself 

 and the environment, the aim of which is the production 

 of the maximum of manifestations, there is the difficulty in 

 assuring oneself that what he gets through these activities 

 are indeed genuine data rather than aberrations of his sense 



