ABSTRACT
The first principle is one which has never ceased to be preached since the time of Bacon: it emphasises the truth that the methods of science are those of observation and experiment: and that as soon as the people travel outside these methods, they become involved in hopeless error and confusion. The second follows from the first: it enjoins upon the reader the principle, never to seek the explanation of some difficult problem by the manufacture of a new and unknown entity. Undoubtedly, however, too much stress on the philosophy or general principles is no less dangerous than too much application to the details. The unfortunate truth remains that either of these subjects—an apprehension of the essential principles on the one hand, and a mastery over the facts on the other hand—is in itself a sufficient task for any ordinary man.
