THE METHOD OF SCIENCE 57 



methods of mathematics, into a theory and, finally, he verifies 

 the theory by deriving from it new conclusions that can be 

 determined by observation. The evolution of the scientific 

 method has depended upon the realization of the importance 

 of these operations and, particularly, of the importance of 

 verification before any theory is allowed to fit into the exist- 

 ing pattern of scientific knowledge. 



When a set of scientific facts can be summarized by a simple 

 statement and, especially, when that statement can be ex- 

 pressed in a mathematical form, it is said to be a law. Physi- 

 cal observations generally are classified by means of laws that 

 can be expressed in mathematical form. 



When a set of observations is finally reduced to a law or 

 mathematical form, the scientist who succeeds in the effort 

 feels a sense of satisfaction and receives the approval of his 

 scientific colleagues, especially if the formula that he has 

 developed covers a wide field of previously unreduced ob- 

 servations. Sometimes, on the other hand, new observations 

 which would be expected to fit into a known formula do not 

 do so. This raises questions as to whether the observations 

 are erroneous, whether some factor has been ignored, or 

 whether the formula is not broad enough to include the new 

 observations. The discovery of facts that are fundamentally 

 new and that require a considerable revision of established 

 laws to represent them is an important event in the history 

 of science and one that is frequently misunderstood, particu- 

 larly by the layman. 



In the nontechnical interpretations of science, whether 

 written by laymen or by professional scientific w^orkers, the 

 nature of scientific theory and law is very rarely borne in 

 mind and made clear to the reader. In any case it is difficult 

 to make the layman understand the nature of a scientific law. 

 This is partly perhaps because of the unfortunate name that 

 has been given to it.* We speak of "laws" in various senses— 



* The origin of the term is discussed by E. Zilsel in his article, 'The 

 Genesis of the Concept of Physical Law," Philosophical Review, LI, 

 245 (May 1942). He points out that the roots of this concept go back 



