THE PLACE OF BIOLOGY. 51 



the absolute determination to conquer, cost what it may. 

 For we are fighting, not merely for our own advantage or 

 safety, but for a higher duty ; and the faith that this 

 higher duty is a real one, and that in following it we are 

 at one with that spiritual reality which is the only reality, 

 gives us a resolution, a courage and a confidence, which 

 could come from no other source. 



What is reality ? Does all the ghastly horror of the 

 battlefield, with its engines and organisation of destruc- 

 tion, represent it ? That is reality no more than the 

 appearance of the physical universe as interpreted by 

 science is reality. But the dying soldier or sailor who 

 thinks not of himself, but cheerily bids his comrades 

 carry on with their duty, has seen and is one with reality. 



The conception of duty itself implies that the spiritual 

 world is a world of imperfection, and yet a world of which 

 the very essence is in the fight with imperfection. We 

 have to tackle the imperfection where we can, and how 

 we can. For this purpose we must study our imperfect 

 world, and act on the best practical knowledge we can 

 get of it. Without the power of predicting the results 

 of our actions we should be helpless. What enables us 

 to predict is science. There is no difference in principle 

 that I can see between the scattered maxims which we 

 call ordinary common sense and the more elementary 

 and far-reaching maxims which we call science. The 

 maxims of common sense vary with the occasions to 

 which they are applicable ; but so also do the maxims 

 of science. Common sense prides itself on being prac- 

 tical, and caring nothing for absolute truth, but only for 

 such truth as is practically sufficient for the occasion ; 

 whereas each of the sciences, as I remarked at the outset 



