138 GENERAL VIEW AND BASIS OP SCIENTIFIC RESEARCH. 



statements or beliefs, one at least must be untrue, and 

 the other may be : and We may judge from this axiomatic 

 fact, and the number of contradictory statements that are 

 extensively believed and taught, the amount of error and- 

 uncertainty which occupies men's minds, and opposes the 

 entrance of verifiable truth. Even in some portions of 

 the physical sciences we still remain ' blind leaders of the 

 blind.' Whilst also there exists in all directions an abun- 

 dance of well-verified knowledge, and a sufficient number 

 of verifiable questions to occupy the thoughts and inves- 

 tigating powers of all mankind for an immense number 

 of ages to come, many persons neglect to improve their 

 intellects, and prefer contradictory beliefs to really true 

 ones. But our minds must be active, and if we do not 

 occupy them with verified truths, we must do so with 

 uncertain beliefs. 



Not only are contradiction and inaccuracy signs of 

 error, but even great exactitude in scientific results is 

 sometimes suspicious, and may indicate what are termed 

 ' cooked results,' because there are always minute errors 

 (different in magnitude in different cases), which we are 

 quite unable, even by the exercise of the greatest care, to 

 avoid. Too great uniformity is also suspicious, because 

 it indicates that extreme instances or exceptional cases 

 have, somehow or other, been missed ; probably in conse- 

 quence of insufficient variety or number of experiments. 

 An error may be proved to be such, directly, by proving the 

 opposite ; or indirectly by proving that it cannot be true. 



Unsuspected circumstances are very treacherous sources 

 of error, and are often due to a peculiarity of the appa- 

 ratus, or a uniform method of working. As they are of 

 very common occurrence, we should never, without suffi- 

 cient reason, assume their absence ; or that the different 

 circumstances of an experiment are independent of each 



