Her is set in a neat and tidy near-future where folks shamble around in comfortable earth-tone clothing, carrying satchels and little personal electronic devices. Joaquin Phoenix is Jonze's protagonist - Theodore, a quiet gent with a prominent mustache who scripts deeply personal cards and eloquent epistles for customers logging onto beautifulhandwrittenletters.com.
Separated from his wife ( Rooney Mara) and accustomed to a solitary life in his high-rise apartment, Theodore goes out and buys a new operating system for his computer. It's called OS1, and it advertises itself as the first sentient system - the tagline: "It's not just an operating system, it's a consciousness."
And then Theodore falls in love with that consciousness. Her name is Samantha, and she is voiced by Scarlett Johansson.
"It's an exploration about relationships and intimacy," says Jonze, on the phone recently from Washington. He argues that his movie isn't necessarily a cautionary tale about our increasing dependence on technology. (Although it's perfectly OK if you see it that way.)
"I wasn't trying to make a message movie, or a satire. With those kinds of things, you're maybe more focused on wanting the audience to take X away from it, something specific. I was more interested in just thinking about exploring things in terms of technology, and the way we live today, or just in terms of relationships, or in terms of how much we need intimacy and how much we prevent ourselves from finding intimacy.
"As well as questions about what is consciousness, and what is love, and what fears we bring into love that prevent us from making connections. I was thinking about all those different things and trying to put them into the film - all these thoughts that sometimes seem contradictory."
If that sounds like Jonze has made a sprawling, talky, thumbsucker of a picture, one of the remarkable things about Her is that, for all the directions it takes off in - and with a supporting cast that includes Amy Adams, Chris Pratt, Kristen Wiig, and Olivia Wilde - it feels streamlined, fleet. Even the (virtual) presence of Alan Watts, the late British philosopher and espouser of Eastern spiritualism, doesn't throw the movie off its rails.
"The reason Alan Watts ended up in the movie," Jonze says, "besides just me liking him, and thinking it would be fun to bring him back as an artificial hyperintelligent version of himself, is that one of the themes he writes a lot about is change, and where pain comes from, in terms of resisting change - whether it's in a relationship, or in life, or in society. . . . And that's one of the themes of the movie as well."
Jonze says he has been kicking around all these ideas for a decade. He started seriously applying himself to Her about five years ago, filling notebooks, mulling plot permutations. And then a couple of years ago, Apple came out with its iPhone Siri commercials - celebrities talking to their phones and their phones talking back.
Including one with a very lonely looking John Malkovich.
Did Jonze think Uh-oh, it's already been done?
"No, I loved that," he says, chuckling. "I mean, anything John Malkovich does, I love.
"And Siri really is a totally different thing. Siri is a voice-command program. I was trying to write a being, write a person, write somebody who was having this experience, who was trying to figure out who she is.
"Yes, she was created artificially, but her feelings feel real to her - and to him.
"And I guess the other reaction I had was that it just seemed exciting. I was like, 'OK, I guess what I've been thinking about for all these years and writing about, it's happening.'
"And that seemed to make the movie even more relevant in a way."