A Dangerous Method is a genuinely interesting movie and, at the same time, a generally dull one. In a story about G.C. Jung, one of the foremost visionaries and interpreters of story archetypes, directed by David Cronenberg, a man who, in his long career, has proved himself more than capable of hallucinatory imagery, we get very little in the way of myth or visual panache.

Screenwriter Christopher Hampton (Dangerous Liasons, Atonement), working from 1993 non-fiction book A Most Dangerous Method by John Kerr and his own play The Talking Cure, does not manage to expand the story to fill the big screen. Like many modern stage plays, the plot is set up as a dialectic: in this case between Sigmund Freud, who believes sex is at the root of psychology and his would-be successor, Jung, who believes that there is more to life — mysticism, parapsychology, precognition, etc.

This is an interesting intellectual debate, and perhaps it bears on the main action, which has Jung struggling with and eventually succumbing to the temptation to sleep with a former patient. Apparently this caused a scandal, but you’d never know it from the effects on the character of Jung, who manages to keep his wife, his family, his job and his reputation; even if he suffers (mostly off-screen) from a broken heart.

What conflict Hampton has allowed into the script, Cronenberg and the cast — Michael Fassbender as Jung, Keira Knightly as the Russian patient-later-pyschiatrist-in-her-own-right Sabina Spielrein, Viggo Mortensen as Freud and Sarah Gadon as Jung’s wife Emma — do a fantastic job with. Certain scenes sizzle with tension. I loved the scene where Jung gives his wife a word-association test, and the ones with Vincent Cassell, as fellow psychiatrist Otto Gross, a man with an unrepressed id.

Freud, Jung, sexual betrayal, paranormal abilities — the elements are fascinating in their own right. I just felt that they were not exploited to their fullest potential. Psychologist Jonathan Haidt has written about a spiritual dimension that can only be perceived by some while others are wholly blind to it. Jung, with his sense of a collective unconscious as well as his moral disgust with his own behavior, is one who perceives that dimension. Freud, who chastises Spielrein’s inclusion of Christ in her paper on suffering, is one who does not perceive it or at least does not give it credence except when it presents him with a chance to strike at Jung, who is poised to tumble him from his perch.

Sadly, I guess the historical record shows their relationship dissolving in a few terse letters. The movie tries to have a confrontation scene before this, with Freud collapsing after being corrected on a point of Egyptian history. But that hardly satisfied the dialectic about mysticism’s place in psychology, nor did the love affair between Jung and Spielrein end in a dramatically gratifying way. As has been the wont of the film, we experience a Chekovian gap of two years, and Spielrein is pregnant and chatty with Jung’s wife. The rest of the story is filled in by title cards — including the dramatic information that Spielrein and her two daughters were murdered by the Nazis while Jung went on to great success and fame. Surely if this was relevant, it was worth filming.

Or maybe they couldn’t afford it. Period films are pricey, and it must have been attractive to confine it to gardens and drawing rooms for budgetary reasons. I wish the filmmakers had either opened up the story for the screen and given it the same lavish treatment as a historical epic like Doctor Zhivago or just kept it as a stage play. Watching Keira Knightly and Michael Fassbender simulate kinky sex might serve as a raison d’être to some audience members, but this audience member likes the foreplay of a well-told story.