MATTER, ENERGY AND LIFE 3 



accuracy to all living organisms, including 

 human beings. From this it may be inferred 

 that, however complex may be the changes 

 involved in organic activity, they are nothing 

 but changes in a material system. As yet ' 

 we are far from being able to trace this 

 system and its changes completely ; but the 

 main outlines are clear, and the gradual filling 

 in of details can only be a matter of time, 

 though we shall probably never succeed in 

 completely filling in all the details. 



It is true that, in the case of at least the 

 higher organisms, consciousness accompanies 

 some of the material changes in the living 

 body, whereas consciousness is not known 

 to accompany material changes in the in 

 organic world. Of this mysterious accom 

 paniment we can of course give no physical 

 account. Possibly consciousness accompanies 

 all material change ; but whether or not this 

 is the case, consciousness seems to make no 

 difference in the end to the physical and 

 chemical chain of events. It might, con 

 ceivably, be a form of energy, generated 

 under certain unknown conditions in active 

 protoplasm ; but, if so, it is only one form 



