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There is something about a poet which leads us to believe that he died, in many cases, as long as 20 years before his birth.
— James Thurber · Selected Letters of James Thurber

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The joke imagines a poet dying before being born, pushing an impression of remoteness into an impossible chronology. The precise span of twenty years makes the absurdity sound considered. One reading concerns the way poets can seem detached from ordinary, present-day life.
Context reviewed