LIFE AND SCIENCE 



to the universe. The force which the engine, or any 

 machine, uses up, reappears as work done, or as heat 

 or light or some other physical manifestation. But 

 the energy of foodstuffs which a man uses up in a 

 mental effort does not appear again in the circuit 

 of the law of the conservation of energy. A man 

 uses up more energy in his waking moments, though 

 his body be passive, than in his sleeping. What we 

 call mental force cannot be accounted for in terms 

 of physical force. The sun's energy goes into our 

 bodies through the food we eat, and so runs our 

 mental faculties, but how does it get back again 

 into the physical realm? Science does not know. 



It must be some sort of energy that lights the 

 lamps of the firefly and the glow-worm, and it must 

 be some sort or degree of energy that keeps con- 

 sciousness going. The brain of a Newton, or of a 

 Plato, must make a larger draft on the solar energy 

 latent in food-stuffs than the brain of a day laborer, 

 and his body less. The same amount of food-con- 

 sumption, or of oxidation, results in physical force 

 in the one case, and mental force in the other, but 

 the mental force escapes the great law of the equiv- 

 alence of the material forces. 



John Fiske solves the problem when he drops his 

 physical science and takes up his philosophy, de- 

 claring that the relation of the mind to the body is 

 that of a musician to his instrument, and this is 

 practically the position of Sir Oliver Lodge. 

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