CHAPTER III. 



QUALITIES OF THEORIES. 



BELIEVABILITY OF THEORIES. 



An examination of the theories, here studied, reveals that some 

 have a much greater probative force than others. This power which 

 a theory has to gain credit for its validity may be called the be- 

 lievability of the theory. To the writer, the theory of inorganic evo- 

 lution and Darwin's theory are the most convincing. A little less 

 so are the theories of ions and that matter is electrical ; while between 

 these four theories and the theories of Locke and Hyslop there seems 

 to be a considerable difference, the latter two theories being much 

 less believable. 



It is true that the confidence of our belief in a theory depends 

 somewhat upon our familiarity with it, the nature of our education, 

 and our general character; yet it is equally certain that there are 

 qualities inherent in the theories themselves which play by far the 

 largest part in determining whether the theory will be believed or not. 

 It is our purpose here, by an examination of the theories, to reveal 

 those qualities upon which believability depends. 



We are convinced by a brief survey, that it does not depend upon 

 the nature of the problem to be solved by the theory. Darwin's 

 theory was one of origin, and the theory of the electrical nature of 

 matter was one of definition. Both theories are strongly convincing. 

 While Hyslop's theory, like Darwin's, was one of origin ; and Locke's 

 like the theory of electrical matter, was one of definition, yet neither 

 Hyslop's nor Locke's theory is of a believable type. 



Believability seems to have much more dependence upon the \ 

 method of procedure by which the problem is solved. We have 

 found two distinct methods of procedure exhibited by the theories in 

 question, namely: the method of experiment, and that of assumption 

 and deduction. We found in the class using the method of experi- 

 mentation: Darwin's theory, the theory of ions, the theory of inor- 

 ganic evolutions, and the theory that matter is electrical ; while in the 

 class using the method of assumption and deduction, we found Hys- 

 lop's theory and John Locke's. Now all the theories of the first class 

 are of a convincing nature, while those of the second class are not. 

 The theories based upon experimental methods are the believable ones, 



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