A sly joke is buried in an early scene in “Code 46,” and darned if it isn’t the key to the whole movie.

We’re in a Shanghai karaoke bar sometime in the near future, and the song is a Vegas-y version of the Clash’s “Should I Stay or Should I Go.” You might not notice it (if you’re not a fan of the Clash, you probably won’t), but the guy singing the karaoke song is, in fact, the Clash’s Mick Jones. The movie doesn’t mention that, but it’s important because it underlines the conundrum of the movie, which is that there are situations where, to paraphrase the Clash, if you stay there will be trouble, and if you leave there will be double.

Tim Robbins is damned if he does and damned if he doesn’t in “Code 46.” He plays a futuristic detective who has contracted an empathy virus that helps him read people’s minds and solve crimes. Early in the movie, he identifies a passport forger (the wondrous Samantha Morton, from “Minority Report”), but he falls in love with her and, very soon, he faces the Clash’s choice: trouble or double.

Watching “Code 46,” you have the uneasy feeling that it – or maybe wizardly director Michael Winterbottom (“Wonderland,” “24 Hour Party People”) – is reading your mind.

The dialogue is sharp (“Everybody’s children are special,” cracks Morton. “Makes you wonder where all the ordinary grown-ups come from.”). And it’s always a couple of steps ahead of us, moving swiftly, not in the car-chases-and-smashups sense but in the throwing-lots-of-info-at-us-and-assuming-we-can-keep-up sense. It’s bracing when a movie honors an audience’s intelligence, and “Code 46” rewards us with a story that asks fascinating questions without pretending to have all the answers.

“Code 46” is a love story, but it’s also about the emotional impact of cloning, which has been perfected in the movie’s time frame. And it’s about our out-of-control environment, which – in the virus-ridden world of the movie – can just barely support life. And it’s about the beautiful experience of feeling like you’re not in step with other people until you find another person who’s not in step in exactly the same way. Ironically, although we expect “futureworlds” to be cold and mechanized, the one in “Code 46” is a place where even clones recognize there is something strong in humanity that will always reach out and connect.

Or will it? It makes sense that the should-I-stay-or-should-I-go world of “Code 46” contains both the most sensual love scene of the year (all close-ups of faces) and the most wrenching love scene. This is a movie that recognizes how vibrant human beings are. And how fragile.