The Unforgetting Machine

The Unforgetting Machine
Illustration: Benjamin Currie (Gizmodo)

Five weeks before Theresa Greenwood vanished, the 64-year-old retiree invited me into her home, let me scratch her cat’s chin, and asked me if I wanted to see into the past. The question was only a courtesy: I had flown 4,500 kilometres to try out the machine she built in her dining room. Sitting down at Greenwood’s cluttered kitchen table, I slipped a wig cap clipped from an old pair of pantyhose onto my head. A jumble of multi-coloured wires dangled from my scalp to a stack of computers on the floor.

Editor’s Note: This article is a work of fiction.

“OK,” said Greenwood, making some final adjustments to my cybernetic hairdo. “Now picture your grandma.”

On the monitor in front of me, a cluster of fleshy blobs emerged from the darkness and congealed into a face. For the first time since I was seven years old, I could see my grandmother. It wasn’t the woman from old photographs or the dim memory I had of my mother’s mother wrapping presents on Christmas morning. With frightening fidelity, the screen showed Florence with sunken cheeks and waxy eyes, looking exactly as she did on the day she died. Seconds later, the face dissolved back into the void.

Greenwood did her best to reassure me as I started to cry. “Don’t worry,” she said, holding a digital camera in one hand. “I recorded it.”


Greenwood didn’t like to call her machine a mind-reading device. “It’s so much more than that,” she said. A patent she filed in 1992 is titled “Method for Transmitting Images From Brain Waves,” but in her first email to me she simply referred to it as her “project.”

“[I] think my project would be very interesting to a journalist like you who isn’t afraid of looking foolish,” said Greenwood, pointing to an article I wrote about exploding toilets. “You should see it.” In a followup email, she hinted that unnamed dark forces would prefer I did not. “Others have ‘caught wind’ of my work so to speak so if I were you I would be looking at plane tickets now.”

As a rule, I don’t respond to basement tinkerers who send me unsolicited emails about inventions that will change the world. (Venture capitalists give the delusional enough encouragement as it is.) Greenwood, however, included footage with her claims. A 15-second video attachment showed a figure sitting in front of a computer monitor as an off-screen voice—hers, I would later learn—shouted commands.

“Think of an elephant!” said the voice. A cartoon elephant appeared on the screen. “Picture your last meal!” A foil-wrapped burrito emerged from the black. “Now think about me!” After a few seconds, the screen flickered. Then the clip ended.

Even if it was just a hoax, I decided, it was too strange to ignore.

The first time we spoke on the phone, Greenwood assured me that her background was in computer science, not parlour tricks. She wouldn’t say where she retired from, but claimed her work with the tech firm left her “comfortable.” According to Greenwood, joining a big company before it took off wasn’t that impressive. “Anybody can do that,” she said. “The real trick is getting out when you still have something left to do.”

For Greenwood, that something was deciphering the hidden language of the human mind. She said she wanted to help people with paralysis communicate, citing “The Menagerie,” a two-part episode of the original Star Trek series, as inspiration.

“In it, there was this space captain who was in some terrible accident and the only way he could talk was by beeping. I said to myself, ‘Tess, put aside a little time and you can do a hell of a lot better than that!’”

After she started working on the project full-time, said Greenwood, progress came quickly. Soon she made a breakthrough: While her machine was impressive when used to visualise a person’s thoughts, it was downright eerie when used to visualise memories.

I observed that I could “visualise memories” pretty well without a machine. Isn’t that what remembering is? Greenwood corrected me.

“What is a memory? It’s just a story that you tell yourself. And each time you think you’re remembering the moment, you’re really just remembering the story—except you don’t know what the words to the story are so you have no idea what parts you’re really remembering and what parts you’re making up on the spot.”

What made her machine so powerful, said Greenwood, was its ability to filter the remembering mind’s dialogue with the past, separating the simply imagined from the truly recalled.

By then, my conversations with the chatty inventor were no longer just a diversion from real work—I needed to know if her claims were true. Greenwood refused to send me more proof. “If you want to learn more, you’ll just have to come here,” she told me.


A month later, I met Greenwood at her house in Everett, Washington, on a cool but clear September morning. Barely five feet tall, she wore her frost-white hair in pigtails and dressed in loose-fitting workwear that swished when she waved her expressive arms. Twice during our interview, she accidentally knocked over something that sent her tortoiseshell cat, Artemis, scurrying for cover. I was surprised the cat wasn’t used to it. There were no decorations on the walls of Greenwood’s home, but piles of electronics crowded every flat surface.

Alan Greenwood, Tess’s 58-year-old brother and housemate, told me her hair started going grey when she was still a teenager. “Anyone who talked to Tess could tell she was the genius of the family,” said Alan, a former sailor who bore an unnerving resemblance to the Austin Powers villain Goldmember. “It seemed only right that she should look it, too.”

If Tess was the mad scientist of the Greenwoods, then Alan was her Igor. He showed me a decades-old snapshot of Tess as a child wearing a red cape and holding a magic wand. At the bottom of the picture was little Alan in bunny ears, almost out of frame.

“For our grand finale, Tess would make me ‘disappear’ and I would run out of the room as fast as I could,” Alan said with a smile. “I don’t think we fooled anyone, but it always got a laugh.”

After Tess left to attend the University of Washington in Seattle, this partnership was put on hold for more than 40 years until Alan moved into the house last July. At first, he didn’t believe Tess’s story about a machine that could look into the past. It was harder to doubt his own eyes. Alan was the one I saw remembering a burrito.

After interviewing the Greenwoods for two hours, it was time to try the machine myself. I was prepared to either stifle laughter or mask my surprise. I didn’t expect to cry. In the video Tess sent me later, I saw the professional detachment I spent years cultivating wither away in seconds.

In short, I felt weird.

If there was anything left to say that day, I couldn’t think of it. I told the Greenwoods I’d be in touch and walked briskly to my car.


Folklore is filled with tales of fortune tellers, prophets, and clairvoyants. Fewer stories have been told about those who can see into the past. There’s not even an accepted word for such a person. (Paranormal researchers sometimes use the term “retrocognitive.”) And why would there be? For one, almost all of us can do it to some degree. For another, prescience is usually considered a mixed blessing. Perfect hindsight is more plainly a curse.

Alone in my motel room that night, I went over some reading material I printed out before my trip. In the 1874 essay “On the Use and Abuse of History for Life,” Friedrich Nietzsche imagines a “man without any power to forget.” He concludes that such a person would be locked in a sort of spiritual paralysis, unable to lift a finger as his distant present dissolves into “the stream of becoming.” It’s possible to live happily without remembering, says Nietzsche, animals do it every day. A life without forgetting, however, would be no life at all.

The Argentine writer Jorge Luis Borges later expanded on this concept with his 1942 story “Funes the Memorious.” After a fall from a horse, Funes finds he can learn Latin in a week, draw one flicker of a fire as easily as he might draw a circle, and recall the exact position of clouds in the sky years later. His nights, however, are sleepless, and words become meaningless to him. “My memory, sir, is like a garbage heap,” he tells the narrator.

Even without perfect recall, I, too, was having trouble sleeping. The loss of my maternal grandmother, who died of uterine cancer in 1994, was a painful memory, but the years had dulled its sharp edges like a river polishing a stone. When I knocked on Tess’s door, that part of my past felt as abstract as the far-off future, no more real than the year 2099. By the time I left her home, the old wound was as raw as a chemical burn.

If my goal was to approach Tess’s claims objectively, then my experience with the memory machine was a complete failure. I didn’t know if Tess’s machine worked how she said it did, but as I lay in bed that night, its results were real enough.

The next day, I drove to Tess’s alma mater to meet with Karl Schubert, a professor of computational neuroscience at the University of Washington. Asked (purely hypothetically, of course) if a mind-reading machine was possible, Schubert squinted and wiggled his bald head.

“I’m an optimist, I play the Powerball twice a week and sometimes I look for real estate on Google Mars,” he told me. “But 10 years ago, I would’ve said, ‘Good luck.’”

According to Schubert, it was advances in machine learning technology, not the hardware itself, that made neuroimaging promising again. With AI, algorithm training sessions that previously would’ve taken centuries could be simulated in an afternoon.

Could a team of, say, two industrious retirees use such an algorithm to turn memories into images, I asked. Schubert wiggled his head more slowly this time. “That is… a bit more Outer Limits,” he said. “If you believe that, then there’s a house on Mars I’d like to sell you.”


On the first day, I was happy to let Tess give me her demonstration without interruption. When I returned to her home, I came with a list of questions and some proposed tests in hand. Sadly, explained Tess, the machine wasn’t working that day. (It seemed pantyhose-based technology was sensitive to increased suspicion.) Another interview, however, would be fine.

After going over some minor details with Tess, I started asking basic technical questions about the machine. How did the headgear get useable data without calibration? Did her algorithm operate locally or in the cloud? With each answer, she became more evasive, citing a need to protect trade secrets. Eventually, everything I asked about was proprietary somehow.

“Look,” said Tess, leaning forward with a fist on her hip. “It’s one thing to check results. That’s only rational. But it seems like you’re trying to call me an idiot or a liar.”

It was an odd reaction from a woman who invited a stranger to check out her homemade mind machine. I explained that I spoke with an expert and just wanted to clear some things up.

“Wait, who did you talk to?” she demanded.

I told Tess about my meeting with Schubert, assuring her we only talked in hypotheticals. Was he, I asked, one of the people she believed had “caught wind” of her work?

At this, she stood up, using all five feet of her stature to tower over me. She was, a recording of the interview would later confirm, pissed. “I didn’t invite you here to tell everybody my business,” she said. “I think you should leave.”

I just had one more question. If she didn’t want anyone asking questions, why contact a reporter at all?

“Well, my son’s a writer and admires your work. I always said he should reach out and thought I’d do it instead but maybe that was a mistake. Goodbye!”

Driving away from the Greenwood’s, I tried to decide which visit had gone worse. (A tie, I concluded.) I expected Tess to be defensive, but her anger surprised me—and she definitely never mentioned a son before. As I merged onto the highway, my phone buzzed. It was a text from Alan, Tess’s brother.

“We should meet,” he wrote.


Sitting between a bathroom pagoda and a huddle of evergreen trees at a Washington State Safety Rest Area, Alan told me a different version of Tess’s life. It sounded more like an apology than a biography—one he had clearly given many times before.

Tess’s early years were happy, yes, but the farther she excelled, said Alan, the lonelier she was. She expected to meet likeminds when she left home. Instead she discovered she was one of a kind. Alan recalled a visit to his sister’s apartment in the late 1970s.

“It was shocking, to be frank,” said Alan. “She lived in this little apartment on Capitol Hill that was almost completely bare. I asked why she didn’t get some nice curtains or something. She said, ‘For who?’”

Tess’s professional success did little to ease her family’s worries. The Greenwood’s mad scientist seemed destined to be alone. That all changed when she became pregnant at the age of 36. The father was a mystery—Tess never even had a boyfriend.

Like Mary, I joked. Alan kindly ignored me. “She called Max her ‘miracle baby.’ I just wish the miracle could’ve lasted a little longer.”

Raising a son as a single mum is hard enough, said Alan, but Tess, while loving, was ill-suited to parenthood. As a sibling, she was charmingly passionate about her interests. As a mother, she was just aloof. Over time, Max began to rebel—what Alan called “looking to be noticed”—engaging in petty vandalism and theft. By 17, he had dropped out of school and gotten into drugs.

A passing semi truck made it hard to hear what Alan said next. I asked him to repeat himself. “I said he died,” he shouted. “Overdosed in a parked car. I don’t think Tess accepted it, really. She was more of a solution-oriented person.” Tess didn’t build the machine to help the infirm, said Alan, she built it to scan and record her best memories of her son.

But why show me, I asked. Alan sighed. “You should really talk to Rebecca,” he said, patting his pockets for a pen as another semi roared by.


“Oh my god,” said Rebecca Chiang over the phone. “I was wondering when someone would ask me about Theresa.”

Chiang was eager to talk, but insisted we do it in person. She suggested a Seattle bar called Purgatory and—with spy novel flair—said she’d be the woman with long dark hair in a blue dress. She didn’t need to be that specific. Purgatory’s mid-day crowd mostly had bald or shaved heads. Chaing was the only one who could pass for a morning show host.

“This place sucks but they have the best taco special,” said Chaing, who declined to give her age. “You’re buying, right?”

Chiang explained that she was still in graduate school when she heard that Tess was looking for an assistant four years ago. While known as being eccentric, Tess also had a reputation for brilliance in the local tech community—a genius that was substantiated by the machine Chiang watched read her own mind. Eager to be part of the next Seattle success story, Chiang dropped out to make it big with Tess.

“I bet she gave you that Star Trek line. You know that’s bullshit, right?”

According to Chiang, the memory machine worked beyond all expectations, but it only represented half of Tess’s plans. No matter how good it was, Chiang realised, it would never go to market. Her boss’s real obsession wasn’t making money—it was reversing fate.

“Theresa had this insane idea that people were just your memories of them,” said Chiang, stopping to cough up a bite of carnitas. “Like if you could copy those somehow, you would have a clone. I was like, ‘Um, no, I’m pretty sure I’m more than just the girl who works in your fucked-up house.’”

While Tess tried to keep the big picture hidden from Chiang, she eventually discovered a computer file about “memory transference” that helped explain her boss’s behaviour. Created shortly after Max’s death, the document described a method for erasing someone’s memories and implanting new ones. Chiang said when she confronted Tess about it she was accused of spying and fired.

“You know she was experimenting on fucking animals, right? No way is that her first cat.” Chiang pulled up a photo of Artemis on her phone, who she said she still worried about. “It was like Tess was just waiting for the right ‘host’ or something.” Chiang paused to grin at what seemed like a wicked thought. “Did she ever tell you her son wanted to be a writer?”


I only planned to spend a week in Washington, but Tess stopped answering my calls after our confrontation. I considered coming back to the house uninvited. Alan advised me to let his sister cool off. I spent the next few days trying to confirm what I’d been told, the inventor now as big a puzzle as her invention.

Chiang’s stated background checked out. She was 28 years old, I learned, and her former faculty advisor expressed disappointment that such a promising student didn’t complete her Ph.D. A visit to the state office of vital statistics verified the date Alan said Max was born. (No father was listed on the birth certificate.) A newspaper obituary confirmed his death.

After earning her master’s degree in 1982, however, Tess’s life went unrecorded. Her working years were a mystery. Amazon, Microsoft, and RealNetworks could find no evidence of employment. She had clearly improved her disappearing act since childhood. Other than a brief news segment in 2009—which focussed on her volunteer work at a local high school—Tess Greenwood moved through the world without leaving so much as a shadow.

Over the phone, Tess cast herself as a spritely genius who stumbled upon a kind of magic. Her brother and former assistant suggested a different role: the Faustian sorcerer who thinks knowledge can conquer death. I wasn’t convinced she fit either part, but without another interview I’d never really know.

The night before I was scheduled to return to New York, the story of Tess and her memory machine had hit a dead end. My outline for the article was mostly gaps. My research thin and goopy. I was drafting a shrugging explanation to my editors when Tess finally emailed me back. In the message, she said she was ready to tell me everything. But first I had to meet her son.


Tess was apologetic as she led me down her basement stairs. Not everyone gets it, she explained, and she was tired of being dismissed as crazy. “I’ve always had this bad habit of getting worked up,” she added. I asked where Alan was (he hadn’t responded to my texts) and Tess told me he was out fishing. It may not have been my brightest idea to follow a stranger from the internet underground, but I needed to see where this path ended.

At the bottom of the stairs, Tess opened the basement door and placed a hand on the wall. “Well,” she said, “here he is. Here’s Max.”

If the rest of her house was an e-waste dump, the basement was a library in a doomsday bunker. The walls were covered in rows of data cassettes labelled sequentially by date. Tess pulled one from a low shelf. She popped the tape into a computer station set up in the middle of the room. “Here,” she said, clicking play. “This is one of my favourites.”

Over the next few hours, I watched scenes from the entire life of a dead man as seen by his adoring mother. Here was Max catching a newt in a stream. Here he was on his last day of middle school. Here was Max learning how to play guitar. Here he was bringing home a wooden Christmas ornament that said “I LOVE YOU.” Each clip was shot with a clarity that was impossible for such old footage. It was obvious these weren’t just home movies.

Tess thought preserving her favourite memories would keep Max alive, but the person I saw on the tapes was a lie by omission. She didn’t show me the fights over curfew, or the totalled car, or the phone calls from police. I never knew Max, but he was surely more than that—not just the little boy Tess found it so easy to love, but also the one she struggled to.

“I hope you understand now,” said Tess, lowering her head. “I can’t let you leave.” At some point during the viewing, I realised, she locked the door behind me. At first, I felt more compassion than fear. Then I saw two stud-like electrodes glinting in the glow of the computer screen. Tess was gripping a stun gun on her lap.


Back in New York, I tried to forget what I saw in Washington. What did make sense was scarcely believable. Filing a story would make it easier to expense the trip, but I was still considering pressing charges.

After Tess tried to trap me, Alan, who was listening from outside the basement, broke down the door. Picking up splinters from the floor of Max’s digital crypt, Tess said that we needed to calm down, she was only teasing. I looked at the stun gun tucked in the back of her jeans and decided I had had enough of her games. It was time to head home.

In the weeks that followed, I chased other leads and wrote other stories. It was boring, honest work that never made me worried about getting kidnapped. Then, on a dreary Wednesday afternoon, I got a Facebook message from Chiang. “[L]ooks like you stirred something up ????,” she wrote. Linked below was a press release from the Department of Justice. Tess had been indicted.

On October 12th, a federal grand jury charged Theresa Greenwood with multiple counts of stealing trade secrets and unauthorised computer access. According to prosecutors, she improperly accessed an unnamed company’s servers on multiple occasions between September 2008 and April 2019, downloading millions of lines of source code and other electronic files. Court documents hinted at a possible sale to foreign nationals.

Tess, however, had not been arrested. She was a fugitive from the law. In a statement to reporters, the FBI asked anyone with information about her whereabouts to come forward. The agency also thanked an anonymous tipster for alerting the government to Tess’s alleged crimes.

Officials were reluctant to tell me anything that wasn’t publicly stated. When pressed, they implied that the name of the company would never be released. It was obvious I wouldn’t learn much over the phone. I had to head back to what was becoming my least favourite town in the world.


On my final visit to the Greenwood home, there was little sign Tess ever lived there. Her piles of electronics had been seized as evidence, leaving only the furniture, Artemis’s cat things, and the few possessions her brother brought when he moved in. Sitting with Alan in the living room, the house felt more crowded by Tess’s absence than it had by her clutter.

“It’s a shame,” said Alan. “It’s like she never existed.”

This time, Alan denied that the memory machine ever worked. She was making good progress, he said, but it wasn’t the kind of thing a person could do on their own, even somebody as smart as his sister. Alan’s reversal put me in an awkward position. I found myself arguing on behalf of the woman who tried to abduct me.

“Let me tell you a story about Tess,” said Alan. “When she was 16, she became obsessed—truly obsessed—with rockets. Read every book she could find on the subject. Decided she was going to build one herself… and nearly blew herself up. After that, she said she didn’t fail at making a rocket, she succeeded in making a bomb. Tess’s machine was like that: another one of her successful failures.”

What about the image of my grandmother? The videos of Max? “A magic trick,” he said. And what Chiang said about “memory transference” and experiments on cats, was any of that true? Alan’s eyes searched the room for Artemis. “I wouldn’t know anything about that.”

Finally, I asked Alan if he had any idea where Tess might be hiding. I couldn’t imagine her away from her home and her projects.

“I don’t think she’s on the run, really,” said Alan. “I suspect she’s dead.” His tone suggested he thought she was better off that way.


According to police, Alan didn’t need to guess if Tess was alive. Two days later, investigators found a blood-stained work shirt that belonged to her in a storage unit rented under Alan’s name. The raid also reportedly uncovered surgical instruments and a “suspicious quantity” of computer parts.

Police say Alan confessing to killing his sister during questioning. He was subsequently arrested and pleaded not guilty in court. As part of a deal with prosecutors, he later changed his plea to no contest. With the killer caught, local news outlets lost interest in the story. Alan now awaits sentencing for the murder of Theresa Greenwood in Snohomish County Jail. Her body was never found.

While I didn’t trust Alan any more than I trusted Tess, it was hard for me to believe he killed her. When he wasn’t idolising his sister, he was justifying her disturbing behaviour to others. Rebecca Chiang (who denied tipping off the FBI) doubted Tess was even dead.

“It just seems like another one of her schemes, y’know?” Chiang told me over the phone. “I wouldn’t be surprised if this was something she was planning forever in case she got caught. And Alan is such a sucker. The whole thing makes me mad, honestly. Theresa is out there laughing at us. I wanted to see her in jail.”

The episode didn’t leave me feeling much better. I had flown to Washington with a smirk, expecting a sideshow act. Instead, I was shown a one-woman tragedy—and forced to confront my own buried grief. Tess thought she could return to the past if she just remembered it well enough. In the process, she helped me recall my own life better, a gift I was struggling to accept.

Against the advice of his lawyer, Alan agreed to talk to me one last time shortly after his arraignment. For half an hour, he would answer any question as long as I kept his comments off the record—a stipulation I’m respecting. Alan also asked me for a favour. Artemis was put in an animal shelter after his arrest. Could I pick up his cat and find her a good home?

I passed the animal shelter twice before I found the right driveway. The grey building was easy to miss, looking more like a church than a kennel. You’d be surprised by how simple it is to pick up a suspected murderer’s pet. Sign here, said the woman at the front desk, handing me back the cat carrier I bought that morning.

Outside, I stopped in the parking lot to take a closer look at Artemis. It can be difficult to spot the spark of recognition in an animal’s eyes. I wondered if she remembered me, and I wondered if she was happy, and I wondered if I’d simply overlooked the patch of frost-white hair on her head before. Most of all, I wondered what my grandmother, a woman whose superlative kindness I barely remembered, would do if she were there.

With no witnesses left to interview, I called the closest thing to a friend. “Hey,” I asked Rebecca Chiang. “Does your building allow pets?”