116 GENERAL VIEW AND BASIS OF SCIENTIFIC RESEARCH. 



phenomena a different observer, who has no special in- 

 terest in the results, is appointed to make the observa- 

 tions, in order to diminish the amount of personal error ; 

 and in other cases (as in that of chemical analysis above- 

 mentioned) the personal error has to be eliminated by 

 means of special contrivances, which are different in 

 almost every different case. Unconscious prejudices are 

 the most dangerous ones. But in some subjects, personal 

 bias cannot be excluded, because the questions treated of 

 act powerfully upon our feelings and emotions ; and if the 

 subjects are also of an un verifiable kind, a chief source of 

 their progress must lie in new truth from without, reflected 

 upon them by the progress of provable knowledge. In 

 this way science is continually purifying religion and other 

 branches of thought. 



Consciousness alsOj when uncorrected by intelligence 

 and reason, is often a great deceiver, not so frequently, 

 however, with regard to the simple fact of feeling (though 

 even in that simple matter it is not infallible) as with 

 respect to the true explanation of it ; it is also far from 

 being a true measure of magnitudes and distances, and in 

 face of the infinity of nature it almost entirely fails. Men, 

 through many centuries, trusting to the unrorrected evi- 

 dence of simple consciousness, believed that every sub- 

 stance was formed of four elements only, viz. earth, air, 

 fire, and water ; and subsequently that they were formed 

 of sulphur, salt, and mercury. Our memory also, or 

 revived consciousness of feelings and ideas, when not cor- 

 rected by the intellect, is even more inexact, and this 

 gives rise to a whole host of mistakes of testimony ,^&c. 



Perversion of consciousness exists not only in the 

 insane, but in a greater or less degree in all persons ; 

 therefore a knowledge of the fallacy of our senses is one of 

 the most important consequences of the study of nature. 



