xxvi.] CHARACTER OF THE EXPERIMENTALIST. 587 



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 com- 

 pare ; but he compares time after time, and then chooses. 



Having once deliberately chosen, the philosopher may 

 rightly entertain his theory with the strongest 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 in- 

 considerable 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 objections, because there 

 may be many interfering causes, and the very consequences 

 of the theory may have a complexity which prolonged 

 investigation by successive generations of men may not 

 exhaust. If, then, a theory exhibit a number of striking 

 coincidences with fact, it must not be thrown aside until at 

 least one conclusive discordance 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 inquiries into the nature of heat 



" In the course of investigation, I have found myself 

 compelled to relinquish some preconceived notions ; but 

 I have not abandoned them hastily, nor, till after a 

 warm and obstinate defence, I was driven from every 

 post." * 



Faraday's life, again, furnishes most interesting illustra- 

 tions of this tenacity of the philosophic mind. Though so 

 candid in rejecting some theories, there were others to 

 which he clung through everything. One of his favourite 

 notions resulted in a brilliant discovery ; another remains 

 in doubt to the present day. 



The Philosophic Character of Faraday. 



In Faraday's researches concerning the connection of 

 magnetism and light, we find an excellent instance of the 

 pertinacity with which a favourite theory may be pursued, 



1 Experimental Inquiry into the Nature oj Heat. Preface, p. xv. 



