Perception and ideation cannot be separated--Perception constituted by addition of image to sensation--Hallucinations--Objections anticipated and answered CHAPTER IV DEFINITION OF THE EMOTIONS Contrary opinions as to nature of emotions--Emotion a phenomenon _sui generis_--Intellectualist theory of emotion supported by Lange and James--Is emotion only a perception? Is effort?--Question left unanswered CHAPTER V DEFINITION OF THE CONSCIOUSNESS--THE RELATION SUBJECT-OBJECT Can thoughts be divided into subject and object?--This division cannot apply to the consciousness--Subject of cognition itself an object--James' opinion examined--Opinion that subject is spiritual substance and consciousness its faculty refuted CHAPTER VI DEFINITION OF THE CONSCIOUSNESS--CATEGORIES OF THE UNDERSTANDING Principle of relativity doubted--Tables of categories: Aristotle, Kant, and Renouvier--Kantian idealism--Phenomenism of Berkeley examined and rejected--Argument of _a priorists_--The intelligence only an inactive consciousness--Huxley's epiphenomenal consciousness--Is the consciousness necessary?--Impossibility of answering this question CHAPTER VII DEFINITION OF THE CONSCIOUSNESS--THE SEPARABILITY OF THE CONSCIOUSNESS FROM ITS OBJECT--DISCUSSION OF IDEALISM Can the consciousness be separated from its object?--Idealists consider the object a modality of the consciousness and thus inseparable, from it--Futility of this doctrine--Object can exist without consciousness CHAPTER VIII DEFINITION OF THE CONSCIOUSNESS--THE SEPARATION OF THE CONSCIOUSNESS FROM ITS OBJECT--THE UNCONSCIOUS Can ideas exist without consciousness?--No consciousness without an object--Can the consciousness die?--Enfeeblement of consciousness how accounted for--Doubling of consciousness in hysterics--Relations of physiological phenomena to consciousness--Consciousness cannot become unconscious and yet exist CHAPTER IX DEFINITIONS OF PSYCHOLOGY Difficulty of defining psychology--Definition by substance--Psychology not the science of the soul--Definition by enumeration: its error--Definition by method contradicts idea of consciousness--Externospection and introspection sometimes confused--Definition by content--Facts cannot be divided into those of consciousness and of unconsciousness--Descartes' definition of psychology insufficient--"Within and without" simile unanalogous--Definition by point of view--Inconsistencies of Ebbinghaus' contention--W. James' teleological theory--Definition by the peculiar nature of mental laws only one possible: why? BOOK III THE UNION OF THE SOUL AND THE BODY CHAPTER I THE MIND HAS AN INCOMPLETE LIFE Problem of union of mind and body stated--Axiom of heterogeneity must be rejected--Phenomena of consciousness incomplete--Aristotle's _relatum_ and _correlatum_ applied to the terms mind and matter CHAPTER II SPIRITUALISM AND IDEALISM