78 Presidential Address 



doubtedly it initiates processes and pro- 

 duces results that without it could not 

 have occurred, from a bird's nest to a 

 honeycomb, from a deal box to a warship. 

 The behaviour of a ship firing shot and 

 shell is explicable in terms of energy, but 

 the discrimination which it exercises be- 

 tween friend and foe is not so explicable. 

 There is plenty of physics and chemistry 

 and mechanics about every vital action, 

 but for a complete understanding of it 

 something beyond physics and chemistry 

 is needed. 



And life introduces an incalculable 

 element. The vagaries of a fire or a 

 cyclone could all be predicted by La- 

 place's Calculator, given the initial 

 positions, velocities, and the law of accel- 

 eration of the molecules; but no mathe- 

 matician could calculate the orbit of a 

 common house-fly. A physicist into whose 

 galvanometer a spider had crept would be 

 liable to get phenomena of a kind quite 

 inexplicable, until he discovered the super- 

 natural, i.e., literally superphysical, cause. 

 I will risk the assertion that Life intro- 



