In April 2013, Robert Black, a grad student at California State University, moved into a small apartment in South Pasadena. He and his wife of ten years had decided to split up, and he found himself spending much of that summer alone. He missed his kids: Hayley, Kieran, and Saer. “I needed something structured and regular in my life,” he recalled. On August 2, Black wrote a blog post entitled “On me in 3… 2… 1…” It was a line from the 1993 film Groundhog Day, which he had vowed to watch every day for a year.

The movie, if you’ve managed to miss it, follows a Pittsburgh weatherman named Phil Connors, played with impeccable sourness by Bill Murray. While reporting on the Groundhog Day festivities in Punxsutawney, Pennsylvania, Phil gets trapped in a mysterious time loop that forces him to relive the same day over and over again. By the end of the film, he has learned to embrace humanity and the charm of small-town life, and has won the affection of his producer, Rita (Andie MacDowell).

“Phil Connors,” Black wrote his first post, “is not only a great central character for a good comedy like this—not that there are many comedies like this—but he works as an everyman and he goes through all the emotions we all do every day of our lives. There is time in the film (not to mention the many parts of his journey we don’t see on screen) for joy, for sadness, for arrogance and humility, silliness and seriousness, flippancy and philosophy.”

As Black watched and rewatched the film, mirroring Phil’s repetitious existence, he found endless strands of interpretation. On August 11—day 10 of what he called “The Groundhog Day Project”—he presented a study of gender roles. On September 10 (day 40), he discussed Nietzsche’s concept of eternal recurrence. He offered disquisitions on Carl Jung, Phil as Christ figure, and the color blue. On December 2 (day 147), Black took an online dating quiz and concluded that he was in a relationship with Groundhog Day.

He’s not the only one. In the two decades since the movie was released, it has become a philosophical touchstone, dissected by comedy nerds and PhDs alike. Religious scholars have cast Phil’s predicament as a metaphor for Christian purgatory, or the Buddhist concept of samsara. Military theorists have used it as an analogy for endless war. An economist at the Ludwig von Mises Institute once posited that the film “illustrates the importance of the Mises-Hayek paradigm as an alternative to equilibrium economics.”

The title has become an idiom for futility, deployed on the evening news to describe the Middle East or Congressional gridlock. In 1996,...