CHARACTER OF THE EXPERIMENTALIST. 233 



evidence ; indeed the more a man loves his theory, the 

 more scrupulous should be his attention to its faults. 

 Nothing is more common in life than to meet with some 

 theorist, who, by long cogitation over a single theory, has 

 allowed it to mould his mind, and render him incapable of 

 receiving anything but as a contribution to the truth of 

 his one theory. A narrow and intense course of thought 

 may sometimes lead to great results, but the adoption of 

 a wrong theory at the outset is in such a mind irretriev- 

 able. The man of one idea has but a single chance of 

 truth. The fertile discoverer, on the contrary, chooses 

 between many theories, and is never wedded to any one, 

 unless impartial and repeated comparison has convinced 

 him of its validity. He does not choose and then 

 compare ; but he compares time after time, and then 

 chooses. 



Having once deliberately chosen, the philosopher may 

 rightly entertain his theory with the strongest love and 

 fidelity. He will neglect no objection ; for he may chance 

 at any time to meet a fatal one ; but he will bear in mind 

 the inconsiderable powers of the human mind compared 

 with the tasks it has to undertake. He will see that no 

 theory can at first be reconciled with all possible objec- 

 tions, simply because there may be many interfering causes, 

 or the very consequences of the theory may have a com- 

 plexity which prolonged investigation by successive gene- 

 rations of men may not exhaust. If then, a theory exhibit 

 a number of very striking coincidences with fact, it must 

 not be thrown aside until at least one conclusive dis- 

 cordance is proved, regard being had to possible error in 

 establishing that discordance. In science and philosophy 

 something must be risked. He who quails at the least 

 difficulty will never establish a new truth, and it was 

 not unphilosophic in Leslie to remark concerning his 

 own experimental investigations into the nature of heat 



