262 SCIENCE AND IMMORTALITY 



* flash ' is an affair of consciousness, the (?) ob- 

 jective counterpart of which is a vibration. It 

 is a flash only by your interpretation. Ton are 

 the cause of the apparent incongruity, and you are 

 the thing that puzzles me." 



If the cells of the brain are the source of thought, 

 how do they produce it } We can hardly be 

 satisfied with the explanation of Karl Vogt and 

 Cabanis that the brain secretes thought just as the 

 liver secretes bile. 



All scientific explanation amounts to identifica- 

 tion of the unfamiliar with the familiar. Thus we 

 explain the moon's motion by identifying it with 

 the motion of a falling stone ; we explain the heat 

 of the body by identifying it with the heat of 

 ordinary exudation ; and we explain the aurora 

 borealis by identifying its colours with the colours 

 produced in a Crooke's tube by electrical dis- 

 charges through gases. 



But what identity can we detect between mo- 

 lecular motion and thought 1 " Are you likely," 

 asks Tyndall, " to extract Homer out of the rattling 

 of dice, or the Diff^erential Calculus out of the 

 clash of billiard-balls } " 



And, from another point of view, what is 

 molecular motion } Molecular motion is itself 

 thought, and exists only in thought ; it is really an 

 abstract idea — a concept, as much as height or 



