Pixar’s upcoming feature film Soul, which will debut on Disney+ on December 25, poses big questions about who we are and what makes life special. The movie was directed by Pete Docter, who is responsible for some of the most beloved films of all time, including Monsters Inc., Up and Inside Out. Now, with Soul he examines deep, yet fundamental questions about the human experience. The movie centers on Joe Gardner (Jamie Foxx), a middle school band teacher who dreams of playing jazz for a living. However, on the eve of his big break, an accident lands him in the Great Before where souls are made before being sent to Earth. There he meets a reluctant soul, 22 (Tina Fey), who doesn’t see the appeal of life, and Joe takes it upon himself to show her what makes being human so great.

In an early press day to promote the movie, Docter, along with co-director and writer Kemp Powers and producer Dana Murray, spoke to outlets from around the world, including CBR, about the inspiration behind Soul’s story, how the team ensured the mature themes in this family film wouldn’t go over kids’ heads and the trial and error it took to animate something as ephemeral as a soul.

Docter confessed that the idea for Soul, which took almost five years to make, came from something he wondered every now and then about his own life. "I basically feel like making animated films is what I was born to do," he explained. "And yet there are some days where I find myself wondering, 'Really? Cartoons? Is this really what I'm supposed to be doing with my limited time on Earth?' In fact, in darker days, around now, I wonder sometimes is there any point to it. If I had a choice, would I decide to be born and come live? And so really, it's that thought, that struggle, that became the core of our film."

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"So the basic concept of the film," Docter continued, "became a soul who doesn't want to live meets a soul who doesn't want to die.

"In this case, that meant thinking about what makes us who we are. Where did we get our talents, our skills, our personalities and how are we using them? Given our limited time are we making the most of our lives, and are we using what we have to leave this place better than it was before we got here?"

Interestingly, when we meet Joe, he hasn't managed to attain the success he's hoped for in life; yet, when he lands in the Great Before, he never for a moment questions the value of his life or the purpose he sees in living. This was one of the things Powers said he liked best about the film.

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"There are just so many films, particularly family films, that come out with this idea of chasing your dreams," Powers pointed out, "which it's always kind of like the same kind of story. Like if you believe strong enough, you can accomplish your dreams. But we were really trying to thread a needle I've never seen anyone thread before, which is the people who achieve their dreams aren't the only ones whose lives are of value. Actually, everyone's life has equal value, whether they achieve those dreams or not. And it's about our willingness to be personally satisfied."

Heady stuff, for sure, but the team also noted that the concept is not only highly relatable, but that they were sure to pepper the movie with a lot of humor too. Given the complexities of the ideas driving the movie though, some adults expressed concerns about the ability of kids to grasp the story. Yet in test screenings, kids never had any trouble.

"Kids are super smart and I think a lot of times we underestimate what they're able to pick up on, especially when you make it visual." Docter noted. "If you took either [Soul or Inside Out] and tried to explain it to somebody, you probably would lose the kids. But if you show them and you can create the meaning visually, which is of course what we strive to do on all of our films at Pixar, then I think you get it, both in visuals and of course make it emotional."

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Murray concurred, saying, "I have two small children who've both seen the film, and I think the coolest thing about movies that Pete's made is he really asks big questions and it makes kids ask big questions. And that's really important. And I think shying away is a disservice to kids because they're a lot smarter than you would think."

Docter also added that kids would find plenty to enjoy in the film that would make the deeper concepts more fun, including "the unborn souls that goof around and bump into each other. There's a lot of slapstick in the film. The music was something that kids really leaned into."

When coming up with the visuals for the film, one of the biggest challenges the team encountered was determining how to animate a soul, something that we think of as formless and airy. As a reference, Murray explained, they examined something called aerogel, "the lightest solid material on Earth, and it's used by the aerospace industry. It seemed to suggest the non-physical stuff in our research that we were talking about, but in a way we could actually put it on screen."

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Many Pixar artists, including Jason Deamer who created the concept art seen above, then went to work to make the souls of Soul visual, but it was challenging to imbue them with humanity through things like facial expressions. As a result, Pixar "developed a whole new technique we'd never done before" Murray said. "We added line work to help to define the edges that might otherwise be too fuzzy or that you could see very clearly."

As a result, many of the characters in the Great Before are drawn as "living lines," Powers added, like the character seen in the above still from the movie. "They look simple and they, I think, were the single most complex thing to do in the entire film."

Directed by Pete Docter, Soul stars Jamie Foxx, Tina Fey, Questlove, Phylicia Rashad, Daveed Diggs and Angela Bassett. The film will debut on Disney+ on Dec. 25.

NEXT: Soul: Disney/Pixar Debuts Full Trailer for Film Exploring Life and Death