98 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



from the appearance of an object in a certain physical 

 medium to its character apart from such a medium only if 

 he knows the laws according to which radiations from 

 objects are transmitted by media. He can infer from a 

 pointer reading to the character of the object measured 

 only if he knows the principles according to which the meas- 

 uring instrument was constructed and calibrated. He can 

 infer from a sensation to the character of the object sensed 

 only if he knows something of the nature of nervous im- 

 pulses. Finally, he can infer from data as interpreted by 

 mental factors to the data as uninterpreted only if he knows 

 the principles according to which mental operators work. 

 The totality of such laws should make one acquainted 

 with facts like the following : the distinction between normal 

 and abnormal functioning of the operators; the range of 

 sensitivity, delicacy, extent, etc., of the physical media 

 (instruments), sense organs (considered as recording instru- 

 ments) , and states of mind ; the nature of the transformation 

 which any stimulus undergoes as a result of the functioning 

 of the operator, and hence what may be lost from or added 

 to the object; and so on. It is the task of physics, biology, 

 and psychology to reveal laws of this kind. On the basis of 

 them inference may be justified, for the principles by which 

 one infers the character of an object in a less extensive con- 

 text from its character in a more extensive context are the 

 reverse of the principles according to which the object in 

 its less extensive context causes its appearance in the more 

 extensive context. 



But can one learn the laws of operators? Apparently not, 

 due to what has been commonly called the ego-centric 

 predicament. Since one cannot get away from his own sense 

 organs he can be aware of objects in the physical context 

 only as they appear in the bodily context. Furthermore, 

 since one cannot get away from his own mental state he 

 can be aware of objects in the bodily context only as they ap- 

 pear in the mental context. In order to know how 5-operators 

 act one would be obliged to get an object in the P-context, 



