THE EVOLUTION OF SCIEXTIFIC THEORIES 295 



ciency of our laws, how much more Hkely are we to find limits to 

 the sufficiency of our theories! That science might be spared the later 

 discovery of error, Mach repudiated the atomic theory. But, as we 

 saw in Chapter VII, identification of the "good" in science with the 

 avoidance of error comes close to pure negativism. A "scientific revo- 

 lution" is not the catastrophic revelation of corruption in the body 

 scientific but, rather, the exuberant triumph of an undertaking that 

 cannot approach relative truth otherwise than through relatix e error. 

 Surely Popper is right in insisting that: 



The old scientific ideal of episteme—oi absolutely certain, demon- 

 strable knowledge— has proved to be an idol. . . . 



. . . Bold ideas, unjustified anticipations, and speculative thought, 

 are our only means for interpreting nature: our only organon, our only 

 instrument, for grasping her. And we must hazard them to win our 

 prize. Those among us who are unwilling to expose their ideas to the 

 hazard of refutation do not take part in the scientific game. 



Of those so declining, a few become logicians and epistemologists 

 apparently ill content with their own honorable traditional titles. Such 

 a "philosopher of science" may, quite understandably, still cherish the 

 logician's ideal of an analysis that is tidy, complete, and definitive. 

 Thus Reichenbach considered it quite proper that: 



The philosopher of science is not much interested in the thought 

 processes which lead to scientific discoveries; he. looks for a logical 

 analysis of the completed theory, . . . That is, he is not interested in 

 the context of discovery, but in the context of justification. 



In this chapter we have found heuristic power the focal criterion of 

 judgment of a scientific theory. The theory's eflPectiveness as instru- 

 ment of discovery is the supreme justification for its acceptance by 

 scientists. For them the "context of justification" is included icithin 

 and inseparable from the "context of discovery." If he accepts the 

 Reichenbachian dichotomy, the "philosopher of science" no longer 

 concerns himself with the science practiced by scientists. Sometimes 

 of course he proudly declares as much— as in the following statement 

 which, for me at least, has a ring ominously reminiscent of scholasti- 

 cism, in the most pejorative sense of the term. 



After all, this model [of scientific explanation] is not supposed to be a 

 model of actual scientific practice; it is an ideal to which scientific 

 practice is supposed to conform if it is to be satisfactory. Hence, if a 



