146 NULLIUS IN VERBA 



no sodium exists in the sun. The American was 

 silent for some time, and then said, "But who the 

 'nation cares whether there is sodium in the sun or 

 not ? " He had not the scientific spirit which does 

 care about sodium in the sun. 



Scientific discovery is, as I said, made up of a 

 series of prophecies. You observe fact No. i, and 

 you say if this be so No. 2 ought to be true, and 

 on examination you find this is true, and No. 2 

 suggests No. 3. Or else you find 2 not to be true ; 

 this makes you suspect your original fact, and on 

 carefully going over your observation you find 

 No. I was a mistaken observation. The successful 

 man of science is one to whom familiar objects 

 suggest those prophecies generally known as 

 theories. My father was remarkable for not letting 

 what seem to be trifling facts pass without sug- 

 gesting to him a theory. The flies that are caught 

 on the sundew must have been seen by innumerable 

 people — ^but it remained for him to prove the 

 truth of his guess that some plants possess digestive 

 ferments like our own, and live on the insects they 

 catch and digest. 



The art of being guided by slight indications is 

 softietimes called the method of Zadig, which I 

 learn from Mr. Huxley's essay and not from 

 Voltaire. Mr. Huxley points out that it is not only 

 possible thus to prophecy what will happen, but also 

 to determine what has happened ; and he suggests 

 that there should be a word 'backtell' as well as 

 foretell. Zadig, who was an oriental philosopher, 

 met one day the King's servants in great trouble 

 about the loss of their master's favourite horse. 



