THE REAL WORLD 361 



realist's hope to find intrinsically intelligible an objective real world 

 cannot but seem pathetically futile. 



PHENOMENALISM 



To believe everything and to doubt everything are, says Poincare, 

 two facile substitutes for thought. From the extreme of naive realism 

 we fly to the opposite extreme of phenomenalism, e.g., the opinion 

 that scientific theories are nothing but systems for the economic cor- 

 relation of observables. And, simply because it defends so little, the 

 phenomenalist position is less susceptible to attack. If it is alleged 

 that modern physics is incomprehensible, the phenomenalist replies 

 that he does not pretend to find it intelligible. If it is alleged that sci- 

 ence is shot through and through with humanly enforced conven- 

 tions, the phenomenalist answers that of course we can construct our 

 own framework of comprehensive correlation with whatever conven- 

 tions we choose. If it is alleged that we lack definitive criteria for 

 choice between scientific theories, the phenomenalist asks what cri- 

 terion can be more fundamental than our own convenience. Our laws 

 are but economic descriptions, and physical objects are "conceptu- 

 ally imported into the situation as convenient intermediaries," What 

 could be simpler? 



Suppose this were a logically impregnable position. Even then, as 

 Born notes, we would not be bound to accept it. 



Logical coherence is a purely negative criterion; no system can be 

 accepted without it, but no system is acceptable just because it is 

 logically tenable. 



Solipsism occupies a position far more easily defended than that of 

 any view granting the genuine existence of other people. Yet few 

 among us are convinced solipsists: we go on wrestling hopefully with 

 the difficult epistemological problems a solipsist would dismiss as 

 "meaningless." To this effort we may be further emboldened by rec- 

 ognition that the phenomenalist position is not free from its own 

 characteristic weaknesses. Consider, for example, the confidence with 

 which Mach writes : 



Sensations are not signs of things; but, on the contrary, a thing is a 

 thought-symbol for a compound sensation of relative fixedness. 



