Directed by Spike Jonze. Starring Joaquin Phoenix. Rated 14A.

Until now, former music-vid director Spike Jonze has been content to give wildly imaginative visual treatment to Charlie Kaufman, Maurice Sendak, and others in features like Where the Wild Things Are, Being John Malkovich, and Adaptation. In Her, he finally directs his own screenplay, and it’s a doozy.

Sticking to a glowing pastel palette, he explores the alternately seductive and repellent aura of the very near future. Our reluctant tour guide is Theodore Twombly, played by Joaquin Phoenix with all the gentle introspection absent from his volatile turn in The Master.

Theo makes his living writing letters for people without time or skills to express themselves. He doesn’t actually write; everything he creates is voice-activated, and actualizing thought is the film’s main theme. (Theo’s last name may refer to the late painter Cy Twombly, who specialized in graffiti-style markings on large, pale surfaces. Or not.)

The neatly mustachioed fellow is haunted by the loss of his marriage to a woman (Rooney Mara) who found him too self-absorbed, and this doesn’t help him connect with strangers—as we see during a disastrous first date (with Olivia Wilde, no less). His friendships are stiff, even with long-time pals like the couple played by Matt Letscher and Amy Adams (again flipping the Master switch). And he spends too much spare time with holographic computer games. So it’s no big surprise how quickly he gets attached to his new OS. Imagine Siri with the computing power of 10,000 iPads and the voice of Scarlett Johansson, and consider how close your thumb would stay to the On button.

Initially, Theo introduces his AI muse to the wonders of the tangible world, and the self-named Samantha bewitches him with her aptitude for learning, including in the sexual arena. But it’s only a matter of time before she outgrows his narrow mortality. The smoothly pulsating film has been criticized for finding a fairly conventional finish to such a cutting-edge story. For me, anyway, that’s a reminder that even tomorrow is too far away to call.