C3lEATr\'E SCIENCE 325 



more subtle point is also here involved. Is it not perhaps only those 

 observations we can conceive as "for or against some view" that we 

 will at all recognize as facts? Consider, for example. Bernard's ap- 

 preciation of a significant episode in his own productive career. 



. . . without the original guiding hypothesis, the experimental fact 

 which contradicted it would never have been perceived. 



The reason we so generally overlook the primacy of hypothesis is 

 because very- often the hypothesis most concerned is not, like Ber- 

 nard's, an explicit "guiding hypothesis." But it would seem that the 

 primacy of hypothesis must still obtain even when it is not formu- 

 lated as such at the outset. As a case in point consider that the crude 

 technologic devices known to Galileo had many inadequacies. Of 

 these on^— the 34-foot limit on the action of lift pumps— particularly 

 attracted his attention. Why ? Galileo accepted the theory of horror 

 vacui. Though he may never have formed the hypothesis explicitly, 

 he doubtless supposed that the lifting capacity of a stoutly made 

 pump would be limited only by the powder available to drive it. Be- 

 cause it conflicted with this context of presupposition, the observ ed 

 limit became an observation of interest, a fact worth looking at "the 

 trigger of inquiry" ( Peirce j— a problem the solution of which yielded 

 to Galileo's disciple. Torricelli, the new science of aerostatics. 



The primacy of completely implicit hypotheses is a theme excel- 

 lently developed by \Miorf : 



The familiar saying that the exception proves the rule contains a 

 good deal of wisdom, though from the standpoint of formal logic it 

 became an absurdity as soon as "prove" no longer meant "put on 

 trial." The old saw began to be profound psy chology from the time it 

 ceased to have standing in logic. NVhat it might weU suggest to us to- 

 day is that, if a rule has absolutely no exc^eptions, it is not rec-ognized 

 as a rule or as anything else; it is then part of the background of ex- 

 j>erience of which we tend to remain unconscious. Never having ex- 

 perienced anything in contrast to it, we cannot isolate it and formu- 

 late it as a rule until we so enlarge our experience and expand our 

 base of reference that we encounter an interruption of its regularity. 

 The situation is somewhat analogous to that of not missing the water 

 until the weU runs dry, . . . 



We see now that the primacy of hypothesis can and must be main- 

 tained even as regards that important group of scientific events we 



