Its origin: the craving for knowledge—Its evolution—Utilitarian period: surprise, astonishment, interrogation—Disinterested period: transition forms—Classification according to intellectual states—Classification according to emotional states: dynamic forms, static forms—Period of passion: its rarity—Pathology—Simple doubt—Dramatic doubt—_Folie du doute_—Mysticism in science: deviation comes, not from the object, but from the method of research. CHAPTER XII. NORMAL CHARACTERS 380 Necessity of the synthetic point of view in psychology—Historical summary of theories of character: physiological direction, psychological direction—Two marks of the real character: unity, stability—Elimination of acquired characters—Classificatory procedure: four degrees—Genera: the sensitive, the active, the apathetic—Species—Secondary function of the intellect: its mode of action—Sensitives: the humble, the contemplative, the analytical, the purely emotional—Active type: the medium, the superior—Apathetic type: pure type, intelligent type, calculators—Varieties: the sensitive-active, the apathetic-active, the apathetic-sensitive, the temperate—Substitutes for character: partial characters; (_a_) intellectual form, (_b_) emotional form. CHAPTER XIII. ABNORMAL AND MORBID CHARACTERS 405 Are all normal characters mutually equivalent?—Attempt at classification according to their value-Marks of abnormal character: absence of unity, impossibility of prevision—Class I. Successive contradictory characters: anomalies, conversions; their psychological mechanism. Alternating characters—Second class: Contradictory coexistent characters. Incomplete form: contradiction between principles and tendencies. Complete form. Contradiction between one tendency and another—Third class: Unstable characters. Their physiological and psychological characters—Psychological infantilism. CHAPTER XIV. THE DECAY OF THE AFFECTIVE LIFE 423 Law of Decay: its formula, and its general application in psychology—Difficulties where the affective life is concerned—Successive disappearance of the disinterested emotions (the æsthetic and intellectual), of the altruistic (moral and social), the ego-altruistic (religious feeling, ambition, etc.), and lastly, the egoistic—Converse proof: cases of arrested development—Theory of degeneration—Its relation to decay. CONCLUSION 438 The place of the feelings in psychic life—They come first—Physiological proofs—Psychological proofs.