ii TRUTH AND TESTIMONY 25 



A truthful mind is necessary for the discovery of 

 truth in Nature. There is often a vast difference 

 between the result an investigator expects to find and 

 what he does obtain, but he must put his hopes aside 

 and follow the new light if he is to be a worthy contributor 

 to scientific knowledge. By this method alone are the 

 conclusions and principles reached which form the 

 refined gold of science. Advance is made by the study 

 of cases which cannot be embraced by a general principle, 

 by the possession of an eye to detect exceptions and of 

 a mind willing to examine them instead of putting them 

 aside because they are not in harmony with pre-con- 

 ceived ideas. 



A particular characteristic of Charles Darwin was the 

 receptive mind with which he faced Nature, and the 

 power of seeing exactly how to deal with variations from 

 a general rule. Sir Francis Darwin relates that his 

 father had a favourite gardener, to whom he used to 

 predict the result of an experiment. When, as often 

 happened, the contrary result came out, it was only 

 natural that the gardener should be pleased. On the 

 other hand, Darwin, though he was disappointed, would 

 say as he left the green-house, " The little beasts are 

 doing just what I did not want them to do." He was 

 not the least upset and very often this type of failure 

 heralded quite a new discovery. His love of truth 

 enabled him immediately to abandon his own hypotheses 

 when they ceased to be supported by observation, and 

 to proceed to inquire into the cause of the unlooked-for 

 result. 



Exceptions to rules are welcomed by a scientific 

 investigator not only because the rules have been tested 

 by them and found wanting, but also because they show 

 that there is still further knowledge to be gained. In 



