When watching or reading The Goldfinch, you can make a pretty easy guess as to why Theo Decker (Ansel Elgort) picks up the small wooden panel after a bombing at the Metropolitan Museum of Art. He's confused by what's probably a major concussion, bewildered by his strange surroundings, and willing to follow the orders of the only other person in the room, a dying old man named Welty. Even though Welty was in a dreamlike state himself and didn't really intend for Theo to take the painting, it makes sense to him at the time.
The more pressing question, one that in part drives Donna Tartt's entire novel, is why Theo keeps "The Goldfinch" for all those years. Wouldn't his life have been easier had he handed the priceless 1654 masterpiece over to the authorities in the days after the explosion? Well, yeah, but then we wouldn't have a book or film to enjoy. But let's get a little more high school book report and give a better answer than that, since the movie is much less clear on this matter.
Grieving, Scared Theo
Theo has more than one chance at the beginning to return The Goldfinch to its rightful place. As adults looking in from the outside, we can assume that the Barbours, the police, or anyone else involved (save his strict school headmaster) would forgive him right away. They would understand that it was a weird impulse of the moment, not a malicious theft. A 13-year-old boy who's committed a serious crime, however, probably isn't inclined to think adults would be generous with him.
Since this is a work of literature we're talking about, there's also something deeper going on with Theo, even early on. Practically the last real conversation he has with his mother is about this painting.
"This is just about the first painting I ever reallyloved," she said.
By holding onto the painting, he feels like he's holding onto the last bit of his mother available to him. Unfortunately, this also means he misses the window in which he could have returned The Goldfinch without being prosecuted.
The Goldfinch Is All That Is Real
As Theo is shuffled from his home to the Barbours', and then to his father's empty house in Las Vegas, he's stripped of everything he thought was permanent and stable in his life. He becomes untethered, no longer an author of his own life. Stealing the painting, and then keeping it, are the only acts he has initiated himself. When he sneaks looks at it in his bedroom in Las Vegas, it's like he's reaching for a lifeline, something solid to keep him from washing away with events entirely.
"[E]ven when I couldn't see it I liked knowing it was there for the depth and solidity it gave things, the reinforcement to infrastructure, an invisible, bedrock rightness that reassured me just as it was reassuring to know that far away, whales swam untroubled in Baltic waters and monks in arcane time zones chanted ceaselessly for the salvation of the world," he says in the book. "[W]hen I'd looked at it long enough ... all space appeared to vanish between me and it so that when I looked up it was the painting and not me that was real."
But Theo Is Wrong
The irony is that once Boris steals the painting and replaces it with his civics textbook, the painting is not real at all. Theo has no idea that his touchstone is now completely theoretical. If you want to take this to another level of analysis, even the real painting isn't real — it's a collection of pigment on wood depicting the image of a bird. And when Boris and his associates begin to use the painting as collateral for their criminal transactions, it becomes even more abstract. As a stolen work of art, its "value" is much higher than anyone would pay for it on the black market.
In the end, when The Goldfinch is safe and returned to its rightful home, Theo is wrong one last time when he looks back on his actions and says he played a role in the painting's immortality by his actions.
"I add my own love to the history of people who have loved beautiful things, and looked out for them, and pulled them from the fire, and sought them when they were lost, and tried to preserve them and save them while passing them along literally from hand to hand, singing out brilliantly from the wreck of time to the next generation of lovers, and the next," he says in the novel's last sentence.
Um, nope. What he actually did was prevent anyone but hardenedcriminals from seeing the painting for several years and put it in danger ofbeing destroyed by the elements and by said criminals.
On the other hand, what if it's not Theo talking there? We could read this as author Donna Tartt herself describing what she's done for the painting by giving it a very new kind of fame among readers and now moviegoers. In that case, we'll go back to our very first answer: Theo stole and kept the painting so that we would have a story — and this work of art — to enjoy.