Throughout “Rolling Thunder Revue,” the new film by Martin Scorsese chronicling Bob Dylan’s celebrated barnstorming tour in the fall of 1975, the participants struggle with how best to describe the event. It was like a “con man, carny, medicine show of old,” says Allen Ginsberg; “a circus atmosphere, dog and pony show,” says Sam Shepard; “an experiment in communal existence,” says Joni Mitchell.

In the movie, in theaters and on Netflix this week , Dylan himself starts to explain, saying that he wanted to do something “in the traditional form of a revue,” before cutting himself off.

“I don’t have a clue,” he says. “It’s about nothing, it’s just something that happened 40 years ago. I don’t remember a thing about Rolling Thunder — it happened so long ago, I wasn’t even born.”