70 WOODWARD 



The requirements of official position are remorseless, however, 

 and one must speak his thought although silence with respect 

 to science may appear to be the most urgent need of the hour. 

 In view of these circumstances, it seems best to avoid topics of 

 current interest and to invite your attention to a brief considera- 

 tion of the elements which lie at the basis of scientific investiga- 

 tion and scientific progress. A recurrence to the slow and pain- 

 ful beginnings of knowledge and the first principles evolved 

 therefrom is always instructive ; and it is especially fitting at a 

 time, like the present, when the ardor of research is somewhat 

 in danger of the sedative influences which spring from the 

 popular glorification of triumphant successes. 



The fundamental data from which all scientific knowledge 

 grows are furnished by observation and experiment. After 

 these come the higher steps of comparison, hypothesis, and 

 finally the correlation and unification of phenomena under 

 theory. Even pure mathematics, though long held apart from 

 the other sciences, must be founded, I think, in the last analysis, 

 on observation and experiment. 



Of the infinite variety of phenomena, which appeal to our 

 senses, some, like those of sidereal astronomy, are subject, in 

 the main, to observation only ; while others, like those of ter- 

 restrial physics, chemistry, and biology, are subject to both ob- 

 servation and experiment. All phenomena are more or less 

 entangled. They point backward and forward in time ; any one 

 of them appears and disappears only in connection with others ; 

 and the record any one of them leaves is known only by its 

 interaction with others. Out of this plexus of relations and in- 

 terrelations it is the business of science to discover the condi- 

 tions of occurrence and the laws of the continuity. Happily 

 for man, although the ultimate complexity of phenomena is 

 everywhere very great, it is frequently possible to discern those 

 conditions and occasionally possible to trace out those laws. 

 But the results we reach are essentially first approximations, 

 depending, in general, on the extent to which we may ignore 

 other phenomena than those specially considered. In fact, a 

 first step towards the solution of a problem in science consists 



