32 THE METHOD OF SCIENCE 



times more radical. Exactly as in religion, it depends largely on 

 the fact that the schools, or some of them, value, or seem to their 

 opponents to value, evidence, not in proportion as it is authentic 

 and relevant, but in proportion as it has been gathered by this or 

 that process of inquiry. 



55. Now, of course, both the methods of thinking and the 

 evidence on which the opinions of any school are based may be 

 altogether wrong, and, therefore, their opponents may be right in 

 refusing to use them. But, in that case, the reasons for rejection 

 should be set out plainly and precisely. It is not enough to 

 ignore evidence, or stigmatize thinking as ' deductive,' or ' philo- 

 sophic,' or ' obsolete.' Epithets are very unconvincing to opponents. 

 A reasoned statement ought to justify what in its absence has 

 the appearance of mere prejudice. Otherwise, in the lack of 

 common criteria for facts and methods of thinking, differences of 

 opinion tend to become as irremovable and irrational as those of 

 religious sects. Scientific men, no matter how open-minded, are 

 sure, of course, to differ more or less in opinion, for they differ in 

 knowledge and reflective power ; but sectarian differences arise 

 only when evidence and modes of thought are accepted or rejected 

 on improper grounds. 



56. In the present chapter I shall discuss the question as to 

 what kinds of evidence and processes of thought are permissible 

 in science. Like other men, I belong, more or less exclusively, to 

 a particular school ; but, very naturally, like them, I believe I am 

 not a member of a sect. I recognize, however, the possibility that 

 I, not the people with whom I disagree, may be prejudiced ; at 

 any rate I recognize that my opinions may appear as prejudices to 

 opponents, unless I first demonstrate that the facts and thinking 

 on which they are founded are such as it is right to use. Hereafter, 

 since I shall not have begged the question by merely assuming 

 that certain classes of facts and processes of thought are par- 

 ticularly right or particularly wrong, but shall have stated explicitly 

 the grounds for my convictions, the reader, if he differs from me, 

 will at least have it in his power to indicate exactly and easily 

 where and how I am mistaken. If he finds I am wrong in the 

 present chapter, I am sure he will be wise not to proceed further ; 

 for it is not possible that reasoning that is based on initial inac- 

 curacies of fact or thought can contain anything of value. How- 

 ever, I do not believe he will think me mistaken. He may wonder, 

 indeed, why I have taken the trouble to write the chapter. I am 

 tolerably sure that all of it will seem obviously true and previously 



