12 PROGRESS OF SCIENCE IN THE CENTURY. 



vancement of science ; they are said to stand far above 

 the average in the nineteenth century; perhaps this 

 is in part because they are so " canny," so unwilling 

 to commit themselves unless they are sure. It may 

 even be that the excessive changeableness of Scotch 

 weather has helped to engender the characteristic 

 mood of caution. Sometimes, indeed, the cautious- 

 ness becomes almost morbid, when three saving 

 clauses are inserted in a single sentence. One recalls 

 Stevenson^s story of the sailor : — '^ Bill, Bill,'^ says I, 

 " or words to that effect.^^ 



No doubt the scientific mood is continually making 

 hypotheses or guesses at truth; the scientific use of 

 the imagination is part of our method. But what 

 we have to guard against is the insidious tendency 

 to mistake provisional hypotheses for full-grown 

 theories, and, still worse, for dogmas. 



As Prof. W. K. Brooks says in his Foundations 

 of Zoology : " The hardest of intellectual virtues 

 is philosophic doubt, and the mental vice to which we 

 are most prone is our tendency to believe that lack of 

 evidence for an opinion is a reason for believing some- 

 thing else. . . . Suspended judgment is the greatest 

 triumph of intellectual discipline." As Huxley said 

 — and who has had the scientific mood more strongly 

 developed — " The assertion that outstrips the evi- 

 dence is not only a blunder but a crime." Just as 

 burnt bairns dread the fire, so the scientific mood, 

 often deceived by hearsay evidence, by incomplete 

 induction, by the will-o'-the-wisp glamour of a seduc- 

 tive idea, by inference mixed up with observation, 

 and even by wilful falsehood, becomes more and more 

 cautious, distrustful, " canny." 



Another aspect of the quality of cautiousness 

 which characterises the scientific mood is distrust of 



