THE PRINCIPLES OF ENERGY 53 



them phenomena about which one hesitates to dogmatise. These 

 things may be, as William James said, " the wild beasts of the 

 philosophical desert," but still the^ are beasts ! We do not get 

 rid of them by saying that they are purely subjective, for we do 

 not seem to be quite clear as to what is subjective and what 

 objective, and whether there is any difference ! 



But this is quite clear : dreams, apparitions, spooks, telepathy, 

 and the like, are phenomena that are a nuisance, for they are 

 existences that are not conserved, and so we cannot investigate 

 them. They are not energy transformations, for if they Were 

 they would continue in some other form after they had dis- 

 appeared, and then we could count and measure, and describe and 

 weigh them. We cannot do so, of course, and so most scientific 

 men simply do not " believe " in spooks. They are existences, 

 but they are not real existences. Real things are the things that 

 are conserved. 



And so the law of conservation applies to some things and not 

 to others, and the things to which it does not apply are unreal. 

 That seems to be the best way out of the difficulty. 



Nothing that science can possibly do will disprove the law of 

 conservation. Energy seems to vanish, but, if so, we only say 

 that it has become potential. It may appear to come from 

 nothing, and then we say that potential energy becomes kinetic, 

 and we invent an ether of space to give us an abiding-place for 

 potentialities. The discovery of radio-activity is a good example, 

 and we may refer to it. A fragment of diamond can be made to 

 burn, giving off heat, and transforming almost immediately into 

 carbonic acid gas, which can no longer give off heat. A fragment 

 of radium of the same size, however, gives off heat spontaneously, 

 and continues to do so ; and a physicist who could observe it for 

 a thousand years would find that it was still giving off heat, but 

 that, like the bush that Moses saw, nee tamen consumebatur. To 

 a chemist of the middle of the nineteenth century such a pheno- 

 menon would have seemed to be almost miraculous, yet it is 

 doubtful if he would have distrusted the law of conservation. 

 He would, like Sir J. J. Thomson and Sir Ernest Rutherford, have 

 invented a new kind of " bound energy." 



He would, like the physicists of our own time, have been 

 justified in his faith. His ether and electrons and bizarre atomic 

 systems are pure inventions, but they are real; they continually 

 lead us back to order and not to chaos, and they are the means 



