EMPIKICx\L TOOLS AND EMPIRICISM 165 



mental evidence justified this identification, but it was powerfully 

 supported by theoretical considerations. The more extended qualita- 

 tive examination of the reaction products suggested in 1934, by Ida 

 Noddack, was dismissed as an utterly pointless waste of time and 

 eflFort. Only Rve years later did an adequate chemical characteriza- 

 tion discover the "radium" to be barium— and this discovery at once 

 evoked the wholly novel concept of nuclear fission. 



DRAWING CONCLUSIONS FROM EXPERIMENTS 



Postponing for later consideration the chimeras of methodical induc- 

 tion and crucial experiments, I venture here only a few remarks on 

 the obvious. And surely it is obvious that any harvest of the fruits of 

 empiricism will demand more than logic and empiricism can them- 

 selves supply. Like the facts themselves, a general conclusion yields 

 itself only to him who, instructed by his hypotheses, brings to his 

 study a particular query couched in particular conceptual terms. As- 

 sume all "errors" properly rejected, all "corrections" properly made: 

 even then what we will be able to find in our data is ordinarily de- 

 limited by just what our ideas have prompted us to seek. Possessed 

 by certain theoretic ideas, Dalton found the law of multiple propor- 

 tions in published data available for several years to all; in precisely 

 similar situations Gay-Lussac discovered his law of combining vol- 

 umes, Petit and Dulong the law of atomic heats, and Balmer. . . . 

 Hear Poincare: 



The isolated fact attracts all eyes, those of the layman as well as of the 

 scientist. But what the genuine physicist alone knows how to see is 

 the bond which unites many facts whose analogy is profound but 

 hidden. The story of Newton's apple is probably not true, but it is 

 symbolic; let us then speak of it as if it were tiiie. Well then, we must 

 believe that before Newton plenty of men had seen apples fall; not 

 one knew how to conclude anything therefrom. Facts would be sterile 

 were there not minds capable of choosing among them, discerning 

 those behind which something is hidden, and of recognizing what is 

 hiding, . . . 



. . . We are [then] no longer in the presence of a fact but of a 

 law. And upon that day the real discoverer will not be the workman 

 who has patiently built up certain of these combinations; it will be he 

 who brings to light their kinship. The first will have seen merely the 

 crude fact, only the other will have perceived the soul of the fact. 

 Often to fix this kinship it suffices him to make a new word, and this 



