INTRODUCTION ix✦

CHAPTER I✦

THE EVOLUTION OF LIFE--MECHANISM AND TELEOLOGY

Of duration in general--Unorganized bodies and abstract time--Organized bodies and real duration--Individuality and the process of growing old 1

Of transformism and the different ways of interpreting it--Radical mechanism and real duration: the relation of biology to physics and chemistry--Radical finalism and real duration: the relation of biology to philosophy 23

The quest of a criterion--Examination of the various theories with regard to a particular example--Darwin and insensible variation--De Vries and sudden variation--Eimer and orthogenesis--Neo-Lamarckism and the hereditability of acquired characters 59

Result of the inquiry--The vital impetus 87

CHAPTER II✦

THE DIVERGENT DIRECTIONS OF THE EVOLUTION OF LIFE--TORPOR, INTELLIGENCE, INSTINCT

General idea of the evolutionary process--Growth--Divergent and complementary tendencies--The meaning of progress and of adaptation 98

The relation of the animal to the plant--General tendency of animal life--The development of animal life 105

The main directions of the evolution of life: torpor, intelligence, instinct 135

The nature of the intellect 151

The nature of instinct 165

Life and consciousness--The apparent place of man in nature 176