8 DEGENERA TION. 



antecedent is this appearance brought about?" In 

 scientific inquiry, as in every-day life, a hypothesis — 

 a provisional answer or guess — is the reply ; and the 

 truth of that guess or hypothesis is then tested. This 

 testing is an essential part of the process. '' If my 

 guess be true, then so-and-so as to which I can decide 

 by inspection or experiment, must be true also," is 

 the form which the argument takes, and the inquiry is 

 thus brought to a point where observation can decide 

 the truth of the hypothesis or first guess. In every- 

 day life we have often to be content without fully 

 testing the truth of our guesses, and hurry into action 

 based on such unverified suppositions. Science, on 

 the other hand, can always wait, and demands again 

 and again the testing and verification of guesses 

 before they are admitted as established truths fit to 

 be used in the testing of new guesses and the building 

 up of scientific doctrine. 



The delicately-reared imaginations of great inves- 

 tigators of natural things have from time to time 

 given birth to hypotheses — guesses at truth — which 

 have suddenly transformed a whole department of 

 knowledge, and made the causes of things quite 

 clear which before seemed likely to remain always 



