xxiv CONTENTS 



CHAPTER VII CAUSES OF VARIATION . . 123 



Amphimixis. Fission. Physiogenesis. Psycho- 

 genesis. 



CHAPTER VIII SELECTION 136 



Organic Selection. Natural Selection. Retro- 

 grade Development. Incompleteness of Natural 

 Selection. Preferential Selection. 



CHAPTER IX ISOLATION 168 



Useless characters. Positions of organic stability. 

 Physical Isolation. Physiological Isolation. 



CHAPTER X SUMMARY OF CHAPTERS V TO IX 187 



CHAPTER XI PSYCHOLOGICAL EVOLUTION . 194 



The growth of Natural Philosophy. Effects of the 

 new teaching. 



CHAPTER XII MENTAL PROCESSES . . .207 

 The origin of Mental Variations. The transmission 

 of Mental Variations. The preservation of 

 Mental Variations. iMotives. 



CHAPTER XIII VOLITION AND FREE-WILL . 215 



The three arguments for Determinism. The ex- 

 planation of Free-will. 



CHAPTER XIV MONISM AND DUALISM . . 226 



Our knowledge of Matter. Our knowledge of 

 Mind. Scientific Monism. D ifficultie s. 

 Dualism. 



CHAPTER XV DESIGN IN NATURE . . .246 

 Development of the Earth. The preliminary steps 

 towards Civilisation. 



CHAPTER XVI SECONDARY CAUSES . . .258 

 CHAPTER XVII THE PURPOSE OF EVOLUTION 264 

 CHAPTER XVIII CONCLUSION . . . .271 



APPENDIX I "WHAT IS LIFE?" . . . .283 

 Reprinted from the " Hibbert Journal." 



APPENDIX II LORD KELVIN ON THE DISSI- 

 PATION OF ENERGY 291 



INDEX . 295 



