RATING A THEORY 27 



systematic experimentation was practically unknown 

 until about three hundred and fifty years ago. It 

 marks a very great epoch in human history." 



A theory, as such, is a thing of merely temporary 

 existence. All speculation — hypothesis and theory — 

 represents effort at interpretation of phenomena. In 

 the course of time, sooner or later, inevitably, the 

 "facts" (data of observation and experimentation) 

 tend to establish the correctness of the original or 

 modified interpretation or they invalidate and dis- 

 credit it. If the facts do not support a hypothesis 

 or a theory, it falls to pieces and is forgotten. This 

 has been the fate of numerous hypotheses and 

 theories. In the event that the facts substantiate 

 the interpretation, again a hypothesis or a theory 

 ceases to exist as such; for proof converts speculation 

 into knowledge, and hypothesis and theory into ac- 

 cepted fact. 



Thus, today, the nebular hypothesis, as developed 

 by Laplace, continues to command high admiration, 

 but merely as a brilliant speculation; since it has 

 been shown (particularly by Chamberlin and Moul- 

 ton) that pertinent facts and their mathematical 

 necessities discredit it. 



As Joseph Barrell, of Yale University, says, "A 

 hypothesis, to gain scientific credence, must emerge 

 successful from the test of observed fact and mathe- 



