EXPLANATORY SCIENCE 213 



But a genuine hypothesis explains also in a more far- 

 reaching sense. Every hypothesis is an instrument of dis- 

 covery. As such it must permit the deduction of propositions 

 not included in the list of known descriptive propositions, 

 but such as to be later verified. Every hypothesis must be 

 fruitful. It must direct the attention of the investigator to 

 realms of nature not yet explored, and it must suggest novel 

 experimental set-ups. This function of anticipation, as has 

 already been seen, is a result of acts of creative imagination. 

 The precise way in which it operates in science will be con- 

 sidered in the next chapter. 



REFERENCES 



C. J. Keyser, Thinking about Thinking (New York: Dutton, 1926). 

 Pastures of Wonder (New York: Columbia University, 



1929). 

 R. D. Carmichael, Logic of Discovery (Chicago: Open Court, 1930). 

 J. RuefF, From the Physical to the Social Sciences (Baltimore: Johns 



Hopkins, 1929). 

 Norman Campbell, What Is Science? (London: Methuen, 1921), 



Chap. V. 

 Physics, the Elements (Cambridge: Cambridge University, 



1920), Chap. V. 

 F. M. Chapman and Paul Henle, Fundamentals of Logic (New 



York: Scribners, 1933), Chap. IX. 

 J. W. Young, Fundamental Concepts of Algebra and Geometry 



(New York: Macmillan, 1927), Chaps. IV, V. 

 A. Wolf, Essentials of Scientific Method (New York: Macmillan, 



1925), Chap. IX. 

 A. C. Benjamin, The Logical Structure of Science (London: Kegan 



Paul, 1936), Chap. XIII. 



