540 THE GRAMMAR OF SCIENCE 



disregarded Dr. Wallace's views on the inapplicability of natural 

 selection to the history of man. Such is far from being the fact, but 

 I hold that Dr. Wallace's views as expressed in the chapter (pp. 

 186-214) on The Limits of Natural Selectio7t as applied to Mafi in 

 the recently republished " Natural Selection," and in the chapter on 

 Darwinism applied to Alan in the " Darwinism," will appear 

 paralogistic enough to confute themselves if carefully studied. 



NOTE VII 



On the Reversibility of Natural Processes (p. 349) 



Irreversibility of natural processes is a purely relative conception. 

 History goes forward or backward according to the relative motion 

 of the events and their observer. Conceive a colleague of Clerk- 

 Maxwell's demon (p. 84), gifted with an immensely intensified acute- 

 ness of sight so that he could watch from enormous distances the 

 events of our earth. Now suppose him to travel away from our 

 earth with a velocity greater than that of light. Clearly all natural 

 processes and all history would for him be reversed. Men would 

 enter life by death, would grow younger and leave it finally by birth. 

 Complex types of life would grow simpler, evolution would be 

 reversed, and the earth, growing hotter and hotter, would at last 

 become nebulous. Shortly, by motion to or from the earth, our 

 demon could go forward or backward in history, or with one speed 

 — that of light — live in an eternal now. This conception of historical 

 change and of time as a problem in relative motion was suggested 

 to me by Mr. L. N. G. Filon, and is, I think, of much interest from 

 the standpoint of the pure relativity of all phenomena. 



