68 POPULAR SCIENCE MONTHLY. 



ments, much less the whole of all sets. His record will contain incom- 

 plete parts of different sets of significant elements, but no complete set 

 of any one. The obscure factors of each set are quite sure to be over- 

 looked and the obtrusive factors of several sets indiscriminately com- 

 mingled. The method of colorless observation is thus seriously defec- 

 tive in the completeness of its products, while it successfully guards 

 them from bias. 



Standing over against it, in strong contrast, is the method which 

 at once endeavors to seek out and put together the phenomena that are 

 thought to be significant. This leads promptly to the construction of 

 a theory or an explanation which soon comes to guide the work and 

 gives rise to 



The Method of the Ruling Theory. 



The chief effort here centers on an elucidation of phenomena, not 

 on an exhaustive determination of the facts. Properly enough the 

 crown of the work is the end, explanation is brought to the forefront 

 and eagerly made the immediate end of endeavor. As soon as a phe- 

 nomenon is presented, a theory of elucidation is framed. Laudable 

 enough in itself, the theory is liable to be framed before the phenom- 

 ena are fully and accurately observed. The elucidation is likely to 

 embrace only the more obtrusive phenomena, not the full complement 

 of the obtrusive and the unimpressive. The field is quite likely to 

 present many repetitions of the leading phenomena and a theory 

 framed to fit those that first arrest attention naturally fits the oft- 

 recurrent phenomena of the same class. While there may be really 

 no new evidence, nor any real test, nor any further inquiry into the 

 grounds of the theory, its repeated application with seeming success 

 leads insidiously to the delusion that it has been strengthened by addi- 

 tional investigation. Unconsciously then it begins to direct observa- 

 tion to the facts it so happily elucidates. Unconsciously the facts to 

 which it gives no meaning become less impressive and fall into neglect. 

 Selective observation creeps insidiously in and becomes a persistent 

 habit. Soon also affection is awakened with its blinding influence. 

 The authorship of an original explanation that seems successful easily 

 begets fondness for one's intellectual child. This affection adds its 

 alluring influence to the previous tendency toward an unconscious 

 selection. The mind lingers with pleasure upon the facts that fall 

 happily into the embrace of the theory, and feels a natural indif- 

 ference toward those that assume a refractory or meaningless attitude. 

 Instinctively, there is a special searching-out of phenomena that sup- 

 port the theory; unwittingly also there is a pressing of the theory to 

 make it fit the facts and a pressing of the facts to make them fit the 

 theory. When these biasing tendencies set in, the mind soon glides 

 into the partiality of paternalism, and the theory rapidly rises to a 

 position of control. Unless it happens to be the true one, all hope of the 

 best results is gone. The defects of this method are obvious and grave. 



