August 25, 1905.] 



SCIENCE. 



229 



constitution of the ultimate parts of mat- 

 ter, and he desires further to piece to- 

 gether the past histories and the future 

 fates of planets, stars and nebula?. If 

 then the speculations of the physicist seem 

 in some respects less advanced than those 

 of the biologist, it is chiefly because he is 

 more ambitious in his aims. Physicists 

 and astronomers have not yet found their 

 Johannesburg or Kimberley ; but, although 

 we are still mere prospectors, I am pro- 

 posing to show you some of the dust and 

 diamonds Avhich we have already extracted 

 from our surface mines. 



The fundamental idea in the theory of 

 natural selection is the persistence of those 

 types of life which are adapted to their 

 surrounding conditions, and the elimina- 

 tion by extermination of ill-adapted types. 

 The struggle for life amongst forms pos- 

 sessing a greater or less degree of adapta- 

 tion to slowly varying conditions is held to 

 explain the gradual transmutation of spe- 

 cies. Although a different phraseology is 

 used when we speak of the physical world, 

 yet the idea is essentially the same. 



The point of view from which I wish 

 you to consider the. phenomena of the 

 world of matter may be best explained if, 

 in the first instance, I refer to political in- 

 stitutions, because we all understand, or 

 fancy we understand, something of 

 politics, whilst the problems of physics are 

 commonly far less familiar to us. This 

 illustration will have a further advantage 

 in that it will not be a mere parable, but 

 will involve the fundamental conception of 

 the nature of evolution. 



The complex interactions of man with 

 man in a community are usually described 

 by such comprehensive terms as the state, 

 the commonwealth, or the government. 

 Various states differ widely in their con- 

 stitution and in the degree of the complex- 

 ity of their organization, and we classify 



them by various general terms, such as 

 autocracy, aristocracy or democracy, which 

 express somewhat loosely their leading- 

 characteristics. But, for the purpose of 

 showing the analogy with physics, we need 

 terms of wider import than those habit- 

 ually used in politics. All forms of the 

 state imply inter-relationship in the actions 

 of men, and action implies movement. 

 Thus the state may be described as a con- 

 figuration or arrangement of a community 

 of men; or we may say that it implies a 

 definite mode of motion of man — that is 

 to say an organized scheme of action of 

 man on man. Political history gives an 

 account of the gradual changes in such 

 configurations or modes of motion of men 

 as have possessed the quality of persistence 

 or of stability to resist the disintegrating 

 influence of surrounding circumstances. 



In the world of life the naturalist de- 

 scribes those forms which persist as 

 species ; similarly the physicist speaks of 

 stable configurations or modes of motion 

 of matter; and the politician speaks of 

 states. The idea at the base of all these 

 conceptions is that of stability, or the 

 power of resisting disintegration. In other 

 words, the degree of persistence or per- 

 manence of a species, of a configuration of 

 matter or of a state depends on the perfec- 

 tion of its adaptation to its surrounding 

 conditions. 



If we trace the history of a state we 

 find the degree of its stability gradually 

 changing, slowly rising to a maximum, and 

 then slowly declining. When it falls to 

 nothing a revolution ensues, and a new 

 form of government is established. The 

 new mode of motion or government has at 

 first but slight stability, but it gradually 

 acquires strength and permanence, until 

 in its- turn the slow decay of stability leads 

 on to a new revolution. 



Such crises in political history may give 



