The tendency of metaphysical poetry is toward psychological analysis of the emotions of love and religion. The poet's intent is to speak honestly yet unconventionally of life's complexities.
Dickinson takes the fearful event of dying and makes it seem almost charming and undaunting. He "kindly stops" for her. She put away her schedule--both work and leisure--for his gentile behavior.
He took his time with her, they passed by so many places and things, and then after what seemed a long time to her, the horses turned toward eternity and they rode off calmly, like friends, together with Immortality. The afterlife in heaven.
She takes the fear out of the experience and makes it seem more like an afternoon visit for tea.
A look at something that is considered a complexity of life which usually people react to with fear and anxiety--she has taken it apart and turned this from a psychologically frightening event to something much less daunting and more doable. From this viewpoint, this poem could be considered an example of metaphysical poetry.
The Encyclopedia Britannica defines metaphysical poetry as
Highly intellectualized poetry written chiefly in 17th-century England. Less concerned with expressing feeling than with analyzing it, Metaphysical poetry is marked by bold and ingenious conceits (e.g., metaphors drawing sometimes forced parallels between apparently dissimilar ideas or things), complex and subtle thought, frequent use of paradox, and a dramatic directness of language, the rhythm of which derives from living speech.
Dickinson was heavily influenced by the English Metaphysical poets. "Because I could not stop for death" is an example of directness of language and is written as if the speaker is talking directly to the listener. She sets up the impossible situation that she just doesn't have the time to die. She can't stop for death, so Death comes for her. Then we have a paradox: We usually think of death as something to fear, but she describes "him" as being civil, almost as if he is a suitor coming to woo her away.
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