SCIENTIFIC METHOD 45 



and even dig in the quarry for materials towards so 

 useful a structure than not assist in erecting it.' 



TJie extension of the field of science by logical inference 

 from known phenomena. 



It rarely, probably never, happens that all the members 

 of any causative sequence become known ; there remain 

 gaps in the chain, but the scientific method, with its 

 continual appeal to reason, not infrequently suggests the 

 character of the unknown links. The field of science 

 is thus extended and new methods of observation and 

 experiment are devised in the confident expectation that 

 hidden phenomena of the type inferred will be revealed 

 by their means. 



Sometimes, however, it happens that the known pheno- 

 mena are of so cogent a character that a generalization, 

 including those which are at the time unknown, can 

 be made with logical certainty, a deduction sure to be 

 verified when the appropriate means for further discovery 

 become available. 



It is at first sight curious that such convincing scientific 

 demonstrations, with logical certainty as their intellectual 

 guarantee, should arouse more intense if less general 

 opposition than scientific theories or hypotheses. 



But it must be remembered that this is, after all, 

 a characteristic of human nature. It is referred to by 

 Glanville in the Vanity of Dogmatising as ' men's 

 backwardness to acknowledge their own ignorance and 

 error though ready to find them in others '. So long 

 as an element of doubt is admissible an opponent will 

 suffer the inference to be drawn without a violent out- 

 burst ; but when the inference is logically certain and 

 the opponent is forced to admit his error or stultify 

 himself, then he may, it is true, maintain a magnanimous 



