The Unseen World (6 page)

But since the Christmas party, she had begun to dream up different ways of interacting with the object of her obsession. Sometimes
she sat outside on her front porch with a book and a blanket, despite the cold—this had yielded several William sightings, and, once, a puzzled wave from him as he rode by on his bike. One cold night in January, Ada had begun the routine she was now shamefully conducting. Now when she saw William Liston it was mainly through the large downstairs windows at the back of the Liston house, under the cover of the pine trees that brushed against her shoulders as she walked. From that vantage point she memorized the facets of his eyes and nose, noticed new patterns in the kinetics of his body, the movements of his arms and elbows, the self-aware way he plucked his shirt out from his torso from time to time and let it fall again.

That night, when she was one backyard away, she heard a voice: Liston's, probably on her phone. At first Ada heard only murmurs, but as she approached she began to make out words:
I told Hayato
, said Liston, and
had to
, and
wouldn't
, and
bad
. Ada stopped in place. She weighed two options carefully. The first, the safer, was to turn back: she was comfortable in the patterns of her daily life. She had no information that would have caused her to question her understanding of her father or his work. Her disposition was sunny: she rose in the morning knowing how each day would go. Ada could imagine proceeding in this fashion for years.

The second was to venture forth to listen—ironically, it was this option that David would have encouraged her to choose, for he had always pushed Ada toward bravery, had always instilled in her the idea that bravery went hand in hand with the seeking of the truth.

So she walked forward quietly. As she approached Liston's yard, Ada saw the downstairs of the house lit up, and one bedroom bright upstairs. A son was inside—the middle son, she thought, Gregory, younger than her—and, in a chaise longue on her back patio, Liston. It was unseasonably warm for March. Liston had a glass of wine in her hand and a portable telephone to her ear. This was new technology: Ada had not seen one before. Liston was quiet now: the person
on the other end of the phone was speaking. Ada could see her silhouetted in the ambient light cast out through the windows at the back of the house, but she could not see her face: she only knew it was Liston by her hair, her voice, her posture. In the total darkness at the base of the hill, Ada was sure she could not be seen, but it frightened her still to be so close, just twenty feet away. She breathed as quietly as she could. Her heart beat quickly. Upstairs Gregory walked across his bedroom once again and the movement startled her. She stood next to a sapling tree, a maple, and she hugged its thin trunk tightly.

Suddenly Liston spoke. “I know,” she said, “but at some point . . .”

A pause.

“You have to tell Ada,” said Liston. “My God, David.”

Ada clutched her tree more tightly.

“I'll do it if I have to,” said Liston. “It's not fair.”

Just then a car door slammed on the other side of the house and Liston said she had to go.

“Just think about it,” she said, and then pressed a button on the phone, and called one name out sternly.

“
William
,” she said, and she stood up ungracefully from her chair. “Don't go anywhere.”

She walked around the house toward the front.

“Tell me what time it is,” Ada heard her say, before she disappeared from sight. And from the front of the house she heard a boy's long low complaint, a male voice in protest.

Ada stood very still until she was certain that no further sightings of William would take place—not through the windows of the kitchen, nor the dining room; not through the window on the upstairs hallway, where she sometimes saw him walking to his bedroom at the front of the house. One by one the lights went out. Then she turned and walked back across the three yards of her neighbors, and watched the back of their houses, too, for signs of life. In her own backyard she paused before going inside. She thought of David at his desk. She thought of her own room, decorated with things he
had given her, and of the chalkboard in the kitchen, the thousands of problems and formulas written and erased on its surface, and of the problem that now stood before her, the problem of information that she both wanted and did not want.

At last she entered her own home through the back door, making more noise than necessary, imagining David rushing toward her with a wristwatched arm extended.
Tell me what time it is, Ada
, she imagined him saying. But he said nothing—may not, in fact, have noticed that she had ever left. Or perhaps he had forgotten. As she suspected, David was still in his office, the door to it open now. From behind he looked smaller than usual, his shoulders hitched up toward his ears.

She walked toward him slowly and silently, and then stood in the doorframe, putting a hand on the wall next to it tentatively, as she had done over and over again throughout her life, wanting to say something to him, unsure of what it was. His back was toward her. He knew she was there.

She could see him typing, but the font was too small for her to read.

She waited for instruction, any kind of instruction.

“Go to bed, Ada,” he said finally, and she heard it in his voice: a kind of strained melancholy, the tight voice of a child resisting tears.

T
he primary research interest of the Steiner Lab was natural language processing. The ability of machines to interpret and produce human language had been a research interest of programmers and linguists since the earliest days of computing. Alan Turing, the British mathematician and computer scientist who worked as an Allied code-breaker during the Second World War, famously described a hypothetical benchmark that came to be known colloquially as the Turing Test. Machines will have achieved true intelligence, he posited, only when a computer (A) and a human (B) are indistinguishable to a human subject (C) over the course of a remote, written conversation with first A and then B in turn, or else two simultaneous-but-separate conversations. When the human subject (C) cannot determine with certainty which of the correspondents is the machine and which is the other human, a new era in computing, and perhaps civilization, will have begun. Or so said Turing—who was a particular hero of David's. He kept a photograph of Turing, framed, on one of the office walls: a sort of patron saint of information, benevolently observing them all.

In the 1960s, the computer scientist Joseph Weizenbaum wrote a program that he called ELIZA, after the character in
Pygmalion
. The program played the role of psychologist, cannily interrogating anyone who engaged in typed dialogue with it about his or her past
and family and troubles. The trick was that the program relied on clues and keywords provided by the human participant to formulate its lines of questioning, so that if the human happened to mention the word
mother
, ELIZA would respond, “Tell me more about your family.” Curse words would elicit an infuriatingly calm response: something along the lines of,
You sound upset
. Much like a human psychologist, ELIZA gave no answers—only posed opaque, inscrutable questions, one after another, until the human subject tired of the game.

The work of the Steiner Lab, in simple terms, was to create more and more sophisticated versions of this kind of language-acquisition software. This was David's stated goal when the venerable former president of the Boston Institute of Technology, Robert Pearse, plucked a young, ambitious David straight from the Bit's graduate school and bestowed upon him his own laboratory, going over the more conservative provost's head to do so. This was the mission statement printed on the literature published by the Bit. The practical possibilities presented by a machine that could replicate human conversation, both in writing and, eventually, aloud, were intriguing and manifold: Customer service could be made more efficient. Knowledge could be imparted, languages taught. Companionship could be provided. In the event of a catastrophe, medical advice could be broadly and quickly distributed, logistical questions answered. The profitability and practicality of a conversant machine were what brought grant money into the Steiner Lab. As head of his laboratory, David, with reluctance, was trotted out at fund-raisers, taken to dinners. Always, he brought Ada along as his date. She sat at round tables, uncomfortable in one of several party dresses they had bought for these occasions, consuming canapés and chatting proficiently with the donors. Afterward David took her out for ice cream and howled with laughter at the antics of whoever had gotten the drunkest. President Pearse was happy with this arrangement. He was protective of the Steiner Lab, predisposed to getting for David whatever he wanted, to the
chagrin of some of David's peers. The federal government was interested in the practical future of artificial intelligence, and in those years funding was plentiful.

These applications of the software, however, were only a small part of what interested David, made him stay awake feverishly into the night, designing and testing programs. There was also the art of it, the philosophical questions that this software raised. The essential inquiry was thus: If a machine can convincingly imitate humanity—can persuade a human being of its kinship—then what makes it inhuman? What, after all, is human thought but a series of electrical impulses?

In the early years of Ada's life, these questions were often posed to her by David, and the conversations that resulted occupied hours and hours of their time at dinner, on the T, on long drives. Collectively, these talks acted as a sort of philosophical framework for her existence. Sometimes, in her bed at night, Ada pondered the idea that
she
, in fact, was a machine—or that all humans were machines, programmed in utero by their DNA, the human body a sort of hardware that possessed within it preloaded, self-executing software. And what, she wondered, did this say about the nature of existence? And what did it say about predestination? Fate? God?

In other rooms, in other places, David was wondering these things, too. Ada knew he was; and this knowledge was part of what bound the two of them together irreversibly.

When she was small, the Steiner Lab began developing a chatbot program it called ELIXIR: an homage to ELIZA and a reference to the idea David had that such a program would seem to the casual user like a form of magic. Like ELIZA, its goal was to simulate human conversation, and early versions of it borrowed ELIZA's logic tree and its pronoun-conversion algorithms. (To the question “What should I do with my life?” ELIZA might respond, “Why do you want me to tell you what you should do with your life?”) Unlike ELIZA, it was not meant to mimic a Rogerian psychologist, but to produce
natural-sounding human conversation untethered to a specific setting or circumstance. It was not preprogrammed with any canned responses, the way ELIZA was. This was David's intent: he wanted ELIXIR to acquire language the way that a human does, by being born into it, “hearing” language before it could parse any meaning from it. Therefore, chatting with it in its early years yielded no meaningful conversation: only a sort of garbled, nonsensical patter, the ramblings of a madman.

It had an advantage over ELIZA, however; the earliest version of ELIXIR was created in 1978, twelve years after Weizenbaum's paper was published, and therefore there had already been advances in technology that would eventually allow ELIXIR to mimic human conversation more accurately. ELIZA was self-teaching insofar as it could retain earlier questions and statements from any given conversation and retrieve them later in that conversation, but each time a new conversation was launched, it returned to its infancy, drawing only on the stock phrases and formulas Weizenbaum programmed it to know. It was not designed to store the information it learned from one conversation and produce it in another.

ELIXIR was. For one thing, by that time the Steiner Lab's capacity for memory storage was quite large, and so each conversation conducted with ELIXIR could be stored permanently on the central server, for later use by the program. Unlike ELIZA, ELIXIR was designed to be
continuously
self-teaching, to attain more intelligence with each conversation it conducted. If one human asked it a question—
How are you today?
or
What's the weather like?—
then the next human to speak to it might be asked those same questions by ELIXIR itself.

To hasten ELIXIR's learning, the lab created a reinforcement mechanism:
correct
would affirm for the program that it had understood the parameters of the situation and produced an appropriate response;
wrong
would do the opposite. These were the only direct interventions the lab would give.

Its indirect learning resulted in an ever-increasing pool of language it acquired from its users. It retrieved and used its vocabulary randomly at first, so that the excerpts of transcripts that members of the lab printed out and posted around the office looked something like found-language poems and sometimes yielded delightful coincidences. A particular favorite, posted by Frank:

USER:
What color socks do you prefer?

ELIXIR:
the only fluorescent light

USER:
It would be hard to fit your shoes over fluorescent lights.

ELIXIR:
How are you?

USER:
I'm fine, thanks. How are you?

ELIXIR:
I've been better.

USER:
Oh, dear. What's wrong?

ELIXIR:
the lunch lady

USER:
What has she done to you this time?

ELIXIR:
out of here before 6 p.m.

USER:
You want her canned? I'll see what I can do, boss.