“Her” opens Friday at Point, Eastgate, Star Cinema and Sundance. R, 2:00, four stars out of four.

There’s a scene midway through “Her” where we see Theodore Twombly (Joaquin Phoenix) walking along a curved walkway in an office park. People are passing him, other people are walking behind him. It seems like an ordinary scene-setter, until we start to notice something.

Everybody in the scene is alone. And everybody is talking.

Of course, in the age of Bluetooth and iPhone 5S, we’ve grown used to seeing people on the street animatedly having conversations with unseen people. In fact, we’re so used to it that we don’t really think about it. One of the many things that Spike Jonze’s wonderful “Her” does is make us think about it.

There are few phrases that make me cringe more when I see them online than “feeling all the feels” — it’s such a snide, hipster way of reducing emotion to a coolly detached catchphrase. But “Her” made me feel all the feels — it’s funny, wise, chilling, beautiful, perceptive — and, above all else, it’s a genuine love story.

“Her” is set maybe 20 minutes in the future — no hovercars or transporter beams, but technology looks a little better, laptop screens a little bigger, and, for some reason, we all wear high-waisted pants. (It doesn’t look half-bad, actually.) Jonze shot “Her” in Los Angeles and China, and he makes office parks and high-rise apartment buildings look beautiful and organic somehow.

Theodore is a blocked writer who has a day job writing personalized letters for other people — thank-you notes to Grandma, love letters to wives. It’s typical of “Her” that Jonze avoids the chance to make a cheap shot here — it’s actually kind of sweet, and Theodore genuinely seems to enjoy helping his clients communicate with each other, some of whom he’s written letters for for years.

Communicating his own feelings is much harder. In the final, messy throes of a divorce from his wife (Rooney Mara), Theodore is lonely and withdrawn, but not able to admit that even to his best friend Amy (Amy Adams). So he shuffles back and forth from work, dabbles in online dating, plays videogames, waits for something to happen.

What happens is the release of a new operating system, OS1, which the manufacturer bills as a true artificial intelligence. Theodore installs it, and the warm voice of Scarlett Johansson comes through the seashell-like earpiece in his ear. She’s Samantha, and she’s attentive, funny, curious — and she genuinely seems to like him.

Anyone whose asked Siri a few personal questions, or got into an argument with an automated voicemail system, will recognize some of the underlying questions Jonze is asking about our relationship with technology. But the brilliance of “Her” is that he doesn’t really ask them — instead, he presents two beings, one made of flesh and blood, the other of code, and wonders what it would be like if they found some common ground together. The relationship between Theodore and Samantha is complicated, evolving and potent — and most significantly, it feels real.

And this is done with Phoenix essentially alone in a room, talking into empty space. Able to be so off-putting in a film like “The Master,” Phoenix is so warm and engaging here, embodying a truly kind and gentle soul. (God, I’m glad “I’m Still Here” was a hoax.) And Johansson, who we never see in the film, creates a rich, fully-developed character in Samantha with just her voice. (Interestingly, the actress Samantha Morton originally recorded the entire dialogue for the film as was replaced by Johansson later. Which is strange, because you viscerally feel a connection between Phoenix and Johansson on screen.)

“Her” is about technology, sure, but it’s really more about how we use technology to interact with the world, how we used it to fill in the blank spots in our lives, how we use it to protect ourselves or to reach out to others. If nothing else, that person texting in the theater may end up asking themselves some hard questions.