1C LAY SERMONS, ESSAYS, AND REVIEWS. [i. 



that whenever lie chooses to bring these convictions into contact 

 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 faith, but by verification. 



Thus, without for a moment pretending to despise the practical 

 results of the improvement of natural knowledge, and its bene 

 ficial influence on material civilization, it must, I think, be 

 admitted that the great ideas, some of which I have indicated, 

 and the ethical spirit which I have endeavoured to sketch, in 

 the few moments which remained at my disposal, constitute the 

 real and permanent significance of natural knowledge. 



If these ideas be destined, as I believe they are, to be more 

 and more firmly established as the world grows older; if that 

 spirit be fated, as I believe it is, to extend itself into all depart 

 ments of human thought, and to become co-extensive with the 

 range of knowledge ; if, as our race approaches its maturity, it 

 discovers, as I believe it will, that there is but one kind of 

 knowledge and but one method of acquiring it ; then we, who 

 are still children, may justly feel it our highest duty to recognise 

 the advisableness of improving natural knowledge, and so to aid 

 ourselves and our successors in their course towards the noble 

 goal which lies before mankind. 



