XXIV CONTEXTS OF VOL. I. 



but they lessen with the advance of knowledge — No presumption against the 

 development theory — Arguments from experience against it are worthless — 

 The argument from experience is in its favour — Difficulties about man — Deve- 

 lopment theor)' applicable to man — Man's brain not essentially unlike the ape's 

 — The development of man from the lowest forms is paralleled in the life of 

 every individual — Man's spiritual nature may be a direct result of Creative 

 Power — The law of organic types explained by the theory of development — The 

 development theory does not answer the question of the cause of development 

 • — Geological evidence favours the belief in advance — Reptiles have given way 

 to warm-blooded animals — Geological argument against Darwin's theory — Im- 

 provement goes on most rapidly in the highest classes — Divergence of character 

 — Effect of isolation in producing change — The largest areas produce the most 

 dominant species — General effect of geological conditions — Tendency of geolo- 

 gical changes to constantly greater variation — Correlation of variations — Lowest 

 organisms are most plastic — Classes are usually united by their lowest members 

 — There may be exceptions to this — Apparent inconsistencies of my argument 

 — Life does not supersede, but works through, the properties of matter : so 

 intelligence with unintelligent forces — These relations are inexplicable — We 

 have mental experience of the action of intelligence — Self-adaptation is guided 

 by intelligence — Intelligence determines co-operating variations to occur to- 

 gether — Intelligence is most dominant in the highest life. 



Note A : The Operation of Natural Selection : — Why does natural selection 

 preserve the highest ? — Because the highest are most efficient — Exceptions — 

 Retrograde change — Suctorial j^arasites — Chance of leaving offspring partly 

 determined by fecundity — Rabbit and hare — High organization and fecundity 

 are opposed — Bearing of this law on natural selection — Algebraic statement. 



Note B : — The domestic and wild Guinea-pig do not breed together. Pp. 328 — 341 



CHAPTER XXVI. 



THE RATE OF VARIATION. 



Variation is slow : but I think not so slow as Darwin maintains — Possible sudden 

 origin of new species — Such has occurred under domestication — Poppy — Datura 

 tatula — Ancon sheep — Instinct will prevent crossing — Crossing might not pro- 

 duce a mixed race — Sudden origin of a wild race would not be discovered — 

 Geological time too short for the theory of sloiv variation — Age of the earth, 

 according to Sir W. Thomson — The greyhound an artificial species ; produced 

 in perhaps 500 years, by slow variation : how long would the production of the 

 highest forms from the lowest require, by the same process ? — Variation is slower 

 among wild than tame races — How selection will act in the wild state — Sum- 

 mary — How far I agree with Darwin. 



Note : — Sir William Thomson on the age of the earth . , . , Pp. 342 — 349 



