The answer given above is very helpful. The idea of archetypes presumes that human nature is basically pretty much the same everywhere and always and that certain characters, themes, and symbols therefore tend to be fairly universal. Archetypes (it can be argued) are rooted in very deep-seated desires and fears. Thinking about archetypes is especially assocated with the psychologist Carl Jung, although archetypal thinking may be receiving new support thanks to the study of evolutionary psychology, which can help explain why archetypes arise and why thy tend to persist.
Archeypes are stock characters that have existed as long as humans have been telling stories. The most common archetypes are the hero and the villain. Most specifically, the callow youth hero and the supernatural villain. Others include the old man oracle/wizard and the damsel in distress.
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