192 PART IV.- PREPARATORY STAGE. 



partiality in such a measure that it requires the utmost effort 

 of a generous intellect to mete out the barest justice to a new 

 truth, and not to forget almost instantly that such a truth had 

 been presented and sympathetically entertained. Darwin was 

 fully aware of this. He "remarked that so easy "is it to pass 

 over cases that oppose a favourite generalisation, that he had 

 made it a habit not merely to hunt for contrary instances, but 

 also to write down any exception he noted or thought of 

 otherwise it was almost sure to be forgotten". (John Dewey, 

 How We Think, 1910, p. 90.) 



In truly scientific enquiries psychical bias occasions little 

 havoc, because of the patent reason that trained men of science 

 love truth and hate error very much more than any particular 

 theory. (See, however, last paragraph of this Conclusion.) 

 Hence the psychological mechanism favours here a correct pro- 

 cedure. 1 But to counteract the commonly prevailing tendency, 

 several Conclusions have been suggested, such as 19, 23, 27, 

 and 28, and the objective nature of the Conclusions in the 

 aggregate is likely to defeat this partiality in all but the rarest 

 circumstances. The synthetic and progressive character of the 

 investigation will, moreover, generally veil the ultimate result 

 until the time when it manifests itself unequivocally and can 

 no longer be distorted with impunity. Furthermore, at the 

 service of an objective inquirer, the psychological principle 

 will perform destructive work as efficiently as constructive 

 work, inasmuch as modifying and contradictory evidence will 

 be searched for as zealously as evidence in support. In any 

 case, the thinker should presuppose the pan-human origin of 

 truth, and therefore take it for granted that, however satis- 

 factory his results, they are yet far from being exhaustive or 

 final. 2 



In the cultural sciences, philosophical, religious, economic, 

 .educational, sex, class, national, and racial prejudices and 

 interests, more often than not effectually impede scientific 

 advance, men undertaking to prove or to disprove certain 

 theories because these appeal to them or because they are 

 repelled by them. In industry and commerce the yoke of 

 mechanical routine and narrow self-interest equally obstructs 

 progress. In most of these instances, the brain-twisting bias 

 is unsuspected by the theoriser, and nothing almost will move 



1 " When once we have decided what we will think about, we must think 

 with perfect impartiality on both sides." (Mrs. Boole, Logic Taught by Love, 

 p. 71.) Darwin went even further, and always used the isolated phenomena 

 which were most difficult to explain as tests of the validity of his hypo- 

 theses. (Frank Cramer, op. cit., p. 230.) 



"The chief sources of prejudices are: Imitation, Custom, and Inclination." 

 (Kant, Introduction to Logic, p. 66.) Ribot discusses the relation of the 

 feelings to logic in his La logique des sentiments, Paris, 1905. See also 

 Victor Brochard, De I'erreur, 1879. 



