Improving Natural Knowledge 45 



nounced what is to be believed, and faith has accepted 

 it, reason has no further duty. There are many excellent 

 persons who yet hold by these principles, and it is not my 

 present business, or intention, to discuss their views. All 

 I wish to bring clearly before your minds is the unques- 5 

 tionable fact, that the improvement of natural knowledge 

 is effected by methods which directly give the lie to all 

 these convictions, and assume the exact reverse of each to 

 be true. 



The improver of natural knowledge absolutely refuses 10 

 to acknowledge authority, as such. For him, skepticism 

 is the highest of duties ; blind faith the one unpardon- 

 able sin. And it cannot be otherwise, for every great 

 advance in natural knowledge has involved the absolute 

 rejection of authority, the cherishing of the keenest 15 

 skepticism, the annihilation of the spirit of blind faith ; 

 and the most ardent votary of science holds his firmest 

 convictions, not because the men he most venerates hold 

 them; not because their verity is testified by portents and 

 wonders ; but because his experience teaches him that 20 

 whenever he chooses to bring these convictions into con- 

 tact with their primary source, Nature whenever he 

 thinks fit to test them by appealing to experiment and 

 to observation Nature will confirm them. The man of 

 science has learned to believe in justification, not by 25 

 faith, but by verification. 



Thus, without for a moment pretending to despise 

 the practical results of the improvement of natural knowl- 

 edge, and its beneficial influence on material civilization, 

 it must, I think, be admitted that the great ideas, some 30 

 of which I have indicated, and the ethical spirit which I 

 have endeavored to sketch, in the few moments which re- 

 mained at my disposal, constitute the real and permanent 

 significance of natural knowledge. 



