The Limits of Physical Science. 37 



field, will involve disastrous consequences if it should 

 occur in fixing a base line for the survey of a kingdom. 

 Taking together in one view these five sources of 

 error, to each of which the observer is in every in- 

 stance liable, no one can accept as secure and well- 

 founded any world-embracing hypothesis based on the 

 sciences of observation. Everyone will recognize the 

 wisdom of the caution "We can seldom trust our 

 best established theories and most careful inferences 

 far from their data." * 



* Jevon's Principles of Science, Book VI. , Chap. XXVI. 



