Compared with art, film has a closer relation with truth. It was a spirit of scientific inquiry which drove the first experiments in taking a rapid succession of still photographs.
Perhaps the best known pioneer of moving image is Eadweard Muybridge, whose work can now be seen at Tate Britain. Around 1878, by using multiple cameras, he recorded how horses gallop.
Then there was Albert Londe who worked at the Salpêtrière Clinic in Paris. In 1893 he developed a 12 lens camera for recording fits of hysteria. His serial images were used in early psychiatry.
More than a century later, cinema is still obsessed with both subjects. The action movie is the most bankable Hollywood genre. Psychoanalysis is still a mainstay for reading films.
Now artist Gillian Wearing has made a feature film which reveals as much truth as any other you are likely to see. Her documentary Self Made explores the psychology of seven non actors.
Members of the public were invited to participate in a method acting workshop. The demonstrations of rage, despair, sorrow and alienation are as real as any found in a clinical report.
Moments of action, which include a stabbing and an assault on a pregnant woman, are thankfully staged. But the film offers a real understanding of the emotional dynamic in such events.
Of course cinema has its share of artifice and fantasy. Yet Self Made takes us back to the origins of the medium. It is a project of discovery which just happens to entertain.
Self Made is showing at Vue West End, London, until 21 October: a few more details here. You can read an interview with Gillian Wearing in Time Out here.