Manoel de Oliveira's The Uncertainty Principle is based, like several other of the director's films, on the writing of Agustina Bessa-Luís. The film opens with a long shot of an old cathedral in the rain, as a young woman, Camila (Leonor Baldaque, the granddaughter of Bessa-Luís), surreptitiously enters, presumably to pray, then emerges a short while later. Then the conversation of two brothers, Daniel (Luis Miguel Cintra) and Torcato Roper (José Manuel Mendes), Camila's former tutors, is heard as they describe the central characters of the film. Antonio (Ivo Canelas) is from a wealthy family; he's also the childhood friend of Jose (Ricardo Trêpa, de Oliveira's grandson), the son of his family's maid, Celsa (Isabel Ruth). Jose, who is known as "the Blue Bull" and has been in love with Camila since childhood, is engaged in some kind of shady business practice with Vanessa (de Oliveira stalwart Leonor Silveira), who runs a brothel and a dance club. Thanks to Celsa's machinations, Antonio proposes to Camila, whose family has fallen on hard times. The calculating Camila marries Antonio, who makes little effort to hide his affair with Vanessa. The Uncertainty Principle was shown in competition at the 2002 Cannes Film Festival. It was also selected for the 2002 New York Film Festival.
~ Josh Ralske, All Movie Guide