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Meaning of the title:
Aion was a Hellenistic god who represented time, particularly the concept of time itself rather than specific and segmented time. Aion later became associated with the concept of a supreme God, similar to the Egyptian god Amon-Ra. To Jung, Aion was useful to represent the idea of deep time, mystery, and the duality present in the psyche, such as in the form of the anima and animus.
Anima and Animus:
These are the male and female "components" of each person; that is to say, their internalized conceptions of what is male and what is female, based on their early interactions with their parents.
Ego, Shadow and Self:
These are complex and interactive components of the "active" mind, the deeper unconscious desires that resist moral control, and the summative personality.
Following these definitions, much of the work addresses the history of Christianity in terms of its reflections of these various psychological domains; for example, the Christian fish symbol as a representation of psychology, astrology, alchemy and religion. Jung perceives that the elements of the psyche are evident throughout the various domains and periods because they articulate part of the "collective unconscious" - organizational structures that everyone has in common. For example, the existence of Christ necessitates an Antichrist, because the Antichrist is an embodiment of the shadow.
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