On what Ingmar Bergman's Persona (1966) does that no other film has done with identity.

Persona is usually summarized as a film about two women — a nurse and an actress who has stopped speaking — whose identities gradually merge. The summary is accurate and inadequate. It's like summarizing 2001 as a film about a space mission.

Bergman uses the material of cinema — the film strip, the projection, the celluloid frame — as part of the film's argument. The film breaks in the middle. The image burns. These are not mistakes. They are reminders that you are watching a film, that the identities you're observing are also performances, that the 'real' selves beneath the performances may not exist.

Liv Ullmann and Bibi Andersson give two performances that are among the most studied in cinema. Ullmann says almost nothing for the film's duration and her silence is as active as any spoken performance — it has texture, variation, weight. Andersson talks almost continuously and the talk is an excavation.

The film is Bergman asking whether the self is a performance or a substance, and then declining to answer.