Why? It’s a question that almost every baffling minute of Sia’s profoundly ill-conceived “Music” inspires you to ask in some form or another, often with a different inflection but always with the same urgency. Why did a mega-talented pop star cash in all her chips to make a movie that plays like an unholy cross between Zach Braff’s “Wish I Was Here” and Lars von Trier’s “Dancer in the Dark”? Why, against the advice of virtually every living human and the last vestiges of whatever common sense modern civilization has left, did she cast her able-bodied, neurotypical teenage muse Maddie Ziegler as the nonverbal autistic girl whose name lends the story its title? Why does the script feel like an inspirational Instagram post that was brought to life by a witch’s curse? Why don’t any of the film’s stultifying dance sequences even try to advance the plot or allow its characters to meaningfully express how they feel inside? Why do all of them look like rejected Target commercials from a dystopian back-to-school campaign that was commissioned for the kids in “Logan’s Run”? Why is Music’s sister called “Zu,” why does Zu appear to have a religious objection to wearing shirts, and why did the Golden Globes see fit to nominate Kate Hudson’s blandly well-intentioned performance for Best Actress — Musical or Comedy, when the film around her is music-ish at most and tragic from start to finish?

The good news is that there are easy answers to most of these questions. For example: Zu doesn’t wear shirts because Sia clearly blew the entire makeup and wardrobe budget on Ben Schwartz’s cornrows (he plays a touchy-feely drug dealer),and the script probably feels like it was Human Centipeded together from 400 uplifting Instagram Stories because it was co-written by kid’s lit author and inspirational social media personality Dallas Clayton, whose first son with actress Shannyn Sossamon was famously named “Audio” (short for “Audio Science”). In light of new evidence, it’s safe to assume that name was his idea.

Another thing is apparent: Sia has always believed in magical thinking. It’s unclear if that’s a reason for her success, a direct result of it, or some combination of the two, but a shy girl from Adelaide doesn’t forge a path from Jamiroquai backup singer to global pop superstar and start worshipping a joke god called “Whatever Dude” because she sees the world for its supposed boundaries.

Her life and work have grown increasingly preoccupied with the transformative power of imagination; with the idea that we could all be infinite and loving if not for the bodies that keep holding us back. That explosive force is key to the inside-wants-out energy of bangers like “Breathe Me” and “Chandelier,” but it’s also baked into everything else. From the mega-hits she’s written for other stars, to her controversial decision to anoint a child as her pint-sized stand-in, to the face-obscuring wig she began to perform behind in order to preserve her privacy and buy some distance from her demons, Sia appears determined to dig a tunnel under the border wall that separates who we are and how other people hear us.