Through the conception of the _sub_conscious as resolvable, on the one hand, into the _un_conscious, passive or active physiological dispositions, and, on the other hand, into _co_active conscious states, the subconscious becomes simplified and intelligible. It offers a basis on which may be constructed comprehensible theories of memory, suggestibility, post-hypnotic phenomena, dreams, automatic writing and similar phenomena, artificial hallucinations, the protean phenomena of hysteria, and the psycho-neuroses, as well as the mechanism of thought. It enables us also to construct a rational concept of personality and self. As we shall see, when we take up the study of multiple personality in later lectures, out of the aggregate of the accumulated and varied experience of the past conserved in the unconscious may be constructed a number of different personalities, each depending upon a synthesis and rearrangement of life’s neurograms and innate dispositions and instincts. All dormant ideas with their feeling tones and conative tendencies belong to our personality, but they may be arranged with varying instincts and innate dispositions into a number of differentiated systems, each synthesized into a corresponding personality. In the unconscious may be conserved a vast number of life’s experiences ranging in time almost from the cradle to the grave. The hopes, the wishes, the anxieties of childhood may still be there, lying fallow, but capable of injecting themselves under favoring conditions into our personalities. Properly speaking, from this point of view, aside from certain artificial and pathological conditions, there is, _normally_, no distinct “subconscious _self_,” or “subliminal _self_,” or “secondary _self_,” or “hidden _self_.” In artificial and pathological conditions there may be, as has been frequently shown, a splitting of consciousness and the aggregation into a secondary coconscious system of large systems of ideas which have all the characteristics of personality. This secondary personality (of which the primary personality is not aware) may have its own memories, feelings, perceptions, and thoughts. It may appropriate to itself various complexes of neurograms deposited by the experiences of life which are not at the disposal of the principal personality. Such a coconscious system may properly be spoken of as a subconscious _self_. But there is no evidence that, _normally_, such systems exist. All that we are entitled to affirm is that every individual’s consciousness may include ideas of which he is not aware, and that he has at his disposal, to a greater or less extent, a large unconscious storehouse in which are neurographically conserved a large and varied mass of life’s experiences. These experiences may be arranged in systems, as we shall see in the next lecture, but they do not constitute a “self.” To speak of them as a subconscious, subliminal, secondary, or hidden self is to