Moonwalking with Einstein: The Art and Science of Remembering Everything - Joshua Foer 2012

The Most Forgetful Man in The World

Having met some of the best memories in the world, I decided that my next step would be to try to seek out the worst. What better way to try to begin to understand the nature and meaning of human memory than to investigate its absence? I went back to Google in search of Ben Pridmore’s counterpart in the record books of forgetfulness, and dug up an article in The Journal of Neuroscience about an eighty-four-year-old retired lab technician called EP, whose memory extended back only as far as his most recent thought. He had one of the most severe cases of amnesia ever documented.

A few weeks after returning from Tallahassee, I phoned a neuroscientist and memory researcher named Larry Squire at the University of California, San Diego, and the San Diego VA Medical Center. Squire had been studying EP for over a decade, and agreed to bring me along on one of his visits to the bright bungalow in suburban San Diego where EP lives with his wife. We traveled there with Jen Frascino, the research coordinator in Squire’s lab who visits EP regularly to administer cognitive tests. Even though Frascino has been to EP’s home some two hundred times, he greets her as a total stranger every time.

EP is six-foot-two, with perfectly parted white hair and unusually long ears. He’s personable, friendly, gracious. He laughs a lot. He seems at first like your average genial grandfather. Frascino, a tall, athletic blonde, sits down with me and Squire opposite EP at his dining room table and asks a series of questions that are meant to gauge his basic knowledge and common sense. She quizzes him about what continent Brazil is on, the number of weeks in a year, the boiling temperature of water. She wants to demonstrate what a battery of cognitive tests has already proved: EP has a working knowledge of the world. His IQ is 103, and his short-term memory is entirely unimpaired. He patiently answers the questions—all correctly—with roughly the same sense of bemusement I imagine I would have if a total stranger walked into my house and earnestly asked me if I knew the boiling point of water.

“What is the thing to do if you find an envelope in the street that is sealed, addressed, and has a stamp on it?” Frascino asks.

“Well, you’d put it in the mailbox. What else?” He chuckles and shoots me a knowing, sidelong glance, as if to say, “Do these people think I’m an idiot?” But sensing that the situation calls for politeness, he turns back to Frascino and adds, “But that’s a really interesting question you’ve got there. Really interesting.” He has no idea he’s heard it many times before.

“Why do we cook food?”

“Because it’s raw?” The word raw carries his voice clear across the tonal register, his bemusement giving way to incredulity.

I ask EP if he knows the name of the last president.

“I’m afraid it’s slipped my mind. How strange.”

“Does the name Bill Clinton sound familiar?”

“Of course I know Clinton! He’s an old friend of mine, a scientist, a good guy. I worked with him, you know.”

He sees my eyes widen in disbelief and stops himself.

“Unless, that is, there’s another Clinton around that you’re thinking of—”

“Well, you know, the last president was named Bill Clinton also.”

“He was? I’ll be—!” He slaps his thigh and chuckles, but doesn’t seem all that embarrassed.

“Who’s the last president you remember?”

He takes a moment to search his brain. “Let’s see. There was Franklin Roosevelt ...”

“Ever heard of John F. Kennedy?”

“Kennedy? Hmm, I’m afraid I don’t know him.”

Frascino interjects with another question. “Why do we study history?”

“Well, we study history to know what happened in the past.”

“But why do we want to know what happened in the past?”

“Because it’s just interesting, frankly.”

In November 1992, EP came down with what seemed like a mild case of the flu. For five days he lay in bed, feverish and lethargic, unsure of what was wrong, while inside his head a vicious virus known as herpes simplex was chewing its way through his brain, coring it like an apple. By the time the virus had run its course, two walnut-size chunks of brain matter in EP’s medial temporal lobes had disappeared, and with them most of his memory.

The virus struck with freakish precision. The medial temporal lobes—there’s one on each side of the brain—include the hippocampus and several adjacent regions that together perform the magical feat of turning our perceptions into long-term memories. Memories aren’t actually stored in the hippocampus—they reside elsewhere, in the brain’s corrugated outer layers, the neocortex—but the hippocampal area makes them stick. EP’s hippocampus was destroyed, and without it he is like a camcorder without a working tape head. He sees, but he doesn’t record.

EP has two types of amnesia—anterograde, which means he can’t form new memories, and retrograde, which means he can’t recall old memories either, at least not since about 1950. His childhood, his service in the merchant marine, World War II—all that is perfectly vivid. But as far as he knows, gas costs a quarter a gallon, and man never took that small step onto the moon.

Even though EP has been an amnesic for a decade and a half, and his condition has neither worsened nor improved, there’s still much that Squire and his team hope to learn from him. A case like his, in which nature performs a cruel but perfect experiment, is, to put it crassly, a major boon to science. In a field in which so many basic questions are still unanswered, there is a limitless number of tests that can be performed on a mind like EP’s. Indeed, there are only a handful of other individuals in the world in whom both hippocampi and the key adjacent structures have been so precisely notched out of an otherwise intact brain. Another severely amnesic case is Clive Wearing, a former music producer for the BBC who was struck by herpes encephalitis in 1985. Like EP’s, his mind has become a sieve. Each time he greets his wife, it’s as though he hasn’t seen her in twenty years. He leaves her agonizing phone messages begging to be picked up from the nursing home where he lives. He also keeps an exhaustive diary that has become a tangible record of his daily anguish. But even the diary he finds hard to trust since—like every other object in his life—it is completely unfamiliar. Every time he opens it, it must feel like confronting a past life. It is filled with entries like this one:

9:34 AM: Now I am superlatively, actually awake.

Those scratched-out entries suggest an awareness of his condition that EP, perhaps blissfully, lacks. From across the table, Squire asks EP how his memory is doing these days.

“It’s fair. Hard to say it’s real good or bad.”

EP wears a metal medical alert bracelet around his left wrist. Even though it’s obvious what it’s for, I ask him anyway. He turns his wrist over and casually reads it.

“Hmm. It says memory loss.”

EP doesn’t even remember that he has a memory problem. That is something he discovers anew every moment. And since he forgets that he always forgets, every lost thought seems like just a casual slip—an annoyance and nothing more—the same way it would to you or me.

“There’s nothing wrong with him in his mind. That’s a blessing,” his wife, Beverly, tells me later, while EP sits on the couch, out of earshot. “I suppose he must know something is wrong, but it doesn’t come out in conversation or in his way of life. But underneath he must know. He just must.”

When I hear those words, I’m stung by the realization of how much more than just memories have been lost. Even EP’s own wife can no longer access his most basic emotions and thoughts. Which is not to say that he doesn’t have emotions or thoughts. Moment to moment, he certainly does. When informed of the births of his grandchildren, EP’s eyes welled up each time—and then he promptly forgot that they existed. But without the ability to compare today’s feelings to yesterday’s, he cannot tell any cohesive narrative about himself, or about those around him, which makes him incapable of providing even the most basic psychological sustenance to his family and friends. After all, EP can only remain truly interested in anyone or anything for as long as he can maintain his attention. Any rogue thought that distracts him effectively resets conversation. A meaningful relationship between two people cannot sustain itself only in the present tense.

Ever since his sickness, space for EP has existed only as far as he can see it. His social universe is only as large as the people in the room. He lives under a narrow spotlight, surrounded by darkness. On a typical morning, EP wakes up, has breakfast, and returns to bed to listen to the radio. But back in bed, it’s not always clear whether he’s just had breakfast or just woken up. Often he’ll have breakfast again, and return to bed to listen to some more radio. Some mornings he’ll have breakfast for a third time. He watches TV, which can be very exciting from second to second, though shows with a clear beginning, middle, and end can pose a problem. He prefers the History Channel, or anything about World War II. He takes walks around the neighborhood, usually several times before lunch, and sometimes for as long as three quarters of an hour. He sits in the yard. He reads the newspaper, which must feel like stepping out of a time machine. Iraq? Internet? By the time EP gets to the end of a headline, he’s usually forgotten how it began. Most of the time, after reading the weather, he just doodles on the paper, drawing mustaches on the photographs or tracing his spoon. When he sees home prices in the real estate section, he invariably announces his shock.

Without a memory, EP has fallen completely out of time. He has no stream of consciousness, just droplets that immediately evaporate. If you were to take the watch off his wrist—or, more cruelly, change the time—he’d be completely lost. Trapped in this limbo of an eternal present, between a past he can’t remember and a future he can’t contemplate, he lives a sedentary life, completely free from worry. “He’s happy all the time. Very happy. I guess it’s because he doesn’t have any stress in his life,” says his daughter Carol, who lives nearby. In his chronic forgetfulness, EP has achieved a kind of pathological enlightenment, a perverted vision of the Buddhist ideal of living entirely in the present.

“How old are you now?” Squire asks him.

“Let’s see, fifty-nine or sixty. You got me,” he says, raising his eyebrow contemplatively, as if he were making a calculation and not a guess. “My memory is not that perfect. It’s pretty good, but sometimes people ask me questions that I just don’t get. I’m sure you have that sometimes.”

“Sure I do,” says Squire kindly, even though EP’s almost a quarter of a century off.

Without time, there would be no need for a memory. But without a memory, would there be such a thing as time? I don’t mean time in the sense that, say, physicists speak of it: the fourth dimension, the independent variable, the quantity that compresses when you approach the speed of light. I mean psychological time, the tempo at which we experience life’s passage. Time as a mental construct. Watching EP struggle to recount his own age, I recalled one of the stories Ed Cooke had told me about his research at the University of Paris when we met at the U.S. Memory Championship.

“I’m working on expanding subjective time so that it feels like I live longer,” Ed had mumbled to me on the sidewalk outside the Con Ed headquarters, a cigarette dangling from his mouth. “The idea is to avoid that feeling you have when you get to the end of the year and feel like, where the hell did that go?”

“And how are you going to do that?” I asked.

“By remembering more. By providing my life with more chronological landmarks. By making myself more aware of time’s passage.”

I told him that his plan reminded me of Dunbar, the pilot in Joseph Heller’s Catch-22 who reasons that since time flies when you’re having fun, the surest way to slow life’s passage is to make it as boring as possible.

Ed shrugged. “Quite the opposite. The more we pack our lives with memories, the slower time seems to fly.”

Our subjective experience of time is highly variable. We all know that days can pass like weeks and months can feel like years, and that the opposite can be just as true: A month or year can zoom by in what feels like no time at all.

Our lives are structured by our memories of events. Event X happened just before the big Paris vacation. I was doing Y in the first summer after I learned to drive. Z happened the weekend after I landed my first job. We remember events by positioning them in time relative to other events. Just as we accumulate memories of facts by integrating them into a network, we accumulate life experiences by integrating them into a web of other chronological memories. The denser the web, the denser the experience of time.

It’s a point well illustrated by Michel Siffre, a French chronobiologist (he studies the relationship between time and living organisms) who conducted one of the most extraordinary acts of self-experimentation in the history of science. In 1962, Siffre spent two months living in total isolation in a subterranean cave, without access to clock, calendar, or sun. Sleeping and eating only when his body told him to, he sought to discover how the natural rhythms of human life would be affected by living “beyond time.”

Very quickly Siffre’s memory deteriorated. In the dreary darkness, his days melded into one another and became one continuous, indistinguishable blob. Since there was nobody to talk to, and not much to do, there was nothing novel to impress itself upon his memory. There were no chronological landmarks by which he could measure the passage of time. At some point he stopped being able to remember what happened even the day before. His experience in isolation had turned him into EP. As time began to blur, he became effectively amnesic. Soon, his sleep patterns disintegrated. Some days he’d stay awake for thirty-six straight hours, other days for eight—without being able to tell the difference. When his support team on the surface finally called down to him on September 14, the day his experiment was scheduled to wrap up, it was only August 20 in his journal. He thought only a month had gone by. His experience of time’s passage had compressed by a factor of two.

Monotony collapses time; novelty unfolds it. You can exercise daily and eat healthily and live a long life, while experiencing a short one. If you spend your life sitting in a cubicle and passing papers, one day is bound to blend unmemorably into the next—and disappear. That’s why it’s important to change routines regularly, and take vacations to exotic locales, and have as many new experiences as possible that can serve to anchor our memories. Creating new memories stretches out psychological time, and lengthens our perception of our lives.

William James first wrote about the curious warping and foreshortening of psychological time in his Principles of Psychology in 1890: “In youth we may have an absolutely new experience, subjective or objective, every hour of the day. Apprehension is vivid, retentiveness strong, and our recollections of that time, like those of a time spent in rapid and interesting travel, are of something intricate, multitudinous and long-drawn-out,” he wrote. “But as each passing year converts some of this experience into automatic routine which we hardly note at all, the days and the weeks smooth themselves out in recollection to contentless units, and the years grow hollow and collapse.” Life seems to speed up as we get older because life gets less memorable as we get older. “If to remember is to be human, then remembering more means being more human,” said Ed.

There is perhaps a bit of Peter Pan to Ed’s quest to make his life maximally memorable, but of all the things one could be obsessive about collecting, memories of one’s own life don’t seem like the most unreasonable. There’s something even strangely rational about it. There’s an old philosophical conundrum that often gets bandied about in introductory philosophy courses: In the nineteenth century, doctors began to wonder whether the general anesthetic they had been administering to patients might not actually put the patients to sleep so much as freeze their muscles and erase their memories of the surgery. If that were the case, could the doctors be said to have done anything wrong? Like the proverbial tree that falls without anyone hearing it, can an experience that isn’t remembered be meaningfully said to have happened at all? Socrates thought the unexamined life was not worth living. How much more so the unremembered life?

Much of what science knows about memory was learned from a damaged brain remarkably similar to EP’s. It belonged to another amnesic named Henry Molaison, who went by the initials HM and spent most of his life in a nursing home in Connecticut before dying in 2008. (Individuals in the medical literature always go by initials to protect their identities. HM’s name was revealed after his death.) As a child, HM suffered from epilepsy, which began after a bike accident at age nine. By the time he was twenty-seven, he was blacking out several times a week and unable to do much of anything. A neurosurgeon named William Scoville thought he could relieve HM’s symptoms with an experimental surgery that would excise the part of the brain that he suspected was causing the problem.

In 1953, while HM lay awake on the operating table, his scalp anesthetized, Scoville drilled a pair of holes just above the patient’s eyes. The surgeon lifted the front of HM’s brain with a small metal spatula while a metal straw sucked out most of the hippocampus, along with much of the surrounding medial temporal lobes. The surgery reduced the number of HM’s seizures, but there was a tragic side effect: It soon became clear that he’d also been robbed of his memory.

Over the next five decades, HM was the subject of countless experiments and became the most studied patient in the history of brain science. Given the horrific outcome of Scoville’s surgery, everyone assumed HM would be a singular case study.

EP shattered that assumption. What Scoville did to HM with a metal straw, nature did to EP with herpes simplex. Side by side, the grainy black-and-white MRIs of their brains are uncannily similar, though EP’s damage is a bit more extensive. Even if you have no idea what a normal brain ought to look like, the two gaping symmetrical holes stare back at you like a pair of shadowy eyes.

Like EP, HM was able to hold on to memories just long enough to think about them, but once his brain moved on to something else, he could never bring them back. In one famous experiment conducted by the Canadian neuroscientist Brenda Milner, HM was asked to remember the number 584 for as long as possible. He spoke aloud as he was doing it:

It’s easy. You just remember 8. You see, 5, 8, and 4 add to 17. You remember 8, subtract it from 17 and it leaves 9. Divide 9 in half and you get 5 and 4 and there you are: 584. Easy.

He concentrated on this elaborate mantra for several minutes. But as soon as he was distracted, the number dissolved. He couldn’t even remember that he’d been asked to remember something. Though scientists had known that there was a difference between long- and short-term memory since the late nineteenth century, they now had evidence in HM that the two types of memory processes happened in different parts of the brain, and that without most of the hippocampal area, HM couldn’t turn a short-term memory into a long-term one.

Researchers also learned more about another kind of remembering from HM. Even though he couldn’t say what he’d had for breakfast or name the current president, there were some things that he could recall. Milner found that he could learn complicated tasks without even realizing it. In one landmark study in 1962, she showed that HM could learn how to trace inside a five-pointed star on a piece of paper while looking at its reflection in a mirror. Each time Milner gave HM the task, he claimed never to have tried it before. And yet, each day his brain got better at guiding his hand to work in reverse. Despite his amnesia, he was remembering.

Subsequent studies of amnesics, including tests conducted on EP, have found that people who lose their memories are still capable of yet other kinds of unremembered learning. In one experiment, Squire gave EP a list of twenty-four words to memorize. As expected, within a few minutes, EP had no recollection of any of the words, or even that the exercise had happened at all. When asked whether he’d seen a given word before, he answered correctly only half the time. But then Squire sat EP in front of a computer monitor and gave him a different test. This time, forty-eight words were flashed on the screen for twenty-five milliseconds each, just long enough for the eye to catch some, but not all, of them (an eye blink, by comparison, happens in 100 to 150 milliseconds). Half the words were from the list that EP had read over and forgotten, and half were new. Squire asked EP to read each word after it flashed on the screen. Surprisingly, EP was far better at reading the words he’d seen before than the ones that were new. Even though he had no conscious recollection of them, somewhere in the recesses of his brain they had left an impression.

This phenomenon of unconscious remembering, known as priming, is evidence of an entire shadowy underworld of memories lurking beneath the surface of our conscious reckoning. Though there is disagreement about just how many memory systems there are, scientists generally divide memories broadly into two types: declarative and nondeclarative (sometimes referred to as explicit and implicit). Declarative memories are things you know you remember, like the color of your car, or what happened yesterday afternoon. EP and HM had lost the ability to make new declarative memories. Nondeclarative memories are the things you know unconsciously, like how to ride a bike or how to draw a shape while looking at it in a mirror (or what a word flashed rapidly across a computer screen means). Those unconscious memories don’t seem to pass through the same short-term memory buffer as declarative memories, nor do they depend on the hippocampal region to be consolidated and stored. They rely primarily on different parts of the brain. Motor skill learning takes place largely in the cerebellum, perceptual learning in the neocortex, habit learning in the basal ganglia. As EP and HM have so strikingly demonstrated, you can damage one part of the brain, and the rest will keep on working. Indeed, most of who we are and how we think—the core material of our personalities—is bound up in implicit memories that are off-limits to the conscious brain.

Within the category of declarative memories, psychologists make a further distinction between semantic memories, or memories for facts and concepts, and episodic memories, or memories of the experiences of our own lives. Recalling that I had eggs for breakfast this morning would be an episodic memory. Knowing that breakfast is the first meal of the day is a semantic memory. Episodic memories are located in time and space: They have a where and a when attached to them. Semantic memories are located outside of time and space, as free-floating pieces of knowledge. These two different types of remembering seem to make use of different neural pathways, and rely on different regions of the brain, though both are critically dependent on the hippocampus and other structures within the medial temporal lobes. EP has lost both types of memory in equal measure, but curiously his forgetfulness extends back only for the last sixty or so years. His memories have faded along a gradient.

One of the many mysteries of memory is why an amnesic like EP should be able to remember when the atomic bomb fell on Hiroshima but not the much more recent fall of the Berlin Wall. For some unknown reason, it’s the most recent memories that blur first in most amnesics, while distant memories retain their clarity. This phenomenon is known as Ribot’s Law, after the nineteenth-century French psychologist who first noted it, and it’s a pattern found also in Alzheimer’s patients. It suggests something profound: that our memories are not static. Somehow, as memories age, their complexion changes. Each time we think about a memory, we integrate it more deeply into our web of other memories, and therefore make it more stable and less likely to be dislodged.

But in the process, we also transform the memory, and reshape it—sometimes to the point that our memories of events bear only a passing resemblance to what actually happened. Neuroscientists have only recently begun to observe this process happening inside the brain, but psychologists have understood for a long time that there are qualitative differences between old and new memories. Sigmund Freud first noted the curious fact that older memories are often remembered as if captured by a third person holding a camera, whereas more recent events tend to be remembered in the first person, as if through one’s own eyes. It’s as if things that happened to us become simply things that happened. Or as if, over time, the brain naturally turns episodes into facts.

How this process works at the level of neurons still remains a riddle. One well-supported hypothesis holds that our memories are nomadic. While the hippocampus is involved in their initial formation, their contents are ultimately held in long-term storage in the neocortex. Over time, as they are revisited and reinforced, memories are consolidated in a way that makes them impervious to erasure. They become entrenched in a network of cortical connections that allows them to exist independently of the hippocampus. All this raises a tantalizing question: Were EP’s memories since 1950 completely obliterated when the virus ate its way through his medial temporal lobes, or did those memories just become inaccessible? Did the virus burn down half the house, or did it just throw away the key? We don’t know.

It’s thought that sleep plays a critical role in this process of consolidating our memories and drawing meaning out of them. Rats that have spent an hour running around a track apparently run through the same track in their sleep, and exhibit the same patterns of neural firings with their eyes closed as when they were learning the mazes in the first place. It has been suggested that the reason our own dreams so often feel like a surreal recombination of elements plucked from real life is that they are just the by-product of experiences slowly hardening into long-term memories.

Sitting with EP on the couch in his living room, I wonder if he still dreams. Of course, he can’t tell, but I ask him anyway, just to see what he’ll say. “From time to time,” he tells me matter-of-factly, though his response is most certainly a confabulation. “But dreams are hard to remember.”

We all come into the world as amnesics, and quite a few of us exit just the same. The other day, I was quizzing my three-year-old nephew about his second birthday party. Though the event took place more than a third of a lifetime ago, his recollections were surprisingly exact. He remembered the name of the young guitarist who had entertained him and his friends, and could recite some of the songs they had sung. He remembered the miniature drum set I’d given him as a gift. He remembered eating ice cream with cake. And yet, ten years from now, it is almost certain that he will remember none of this.

Until the age of three or four, almost nothing that happens to us leaves the sort of lasting impression that can be consciously recalled as an adult. The average age that people report having their earliest memory is three and a half, and those tend to be just blurry, fragmentary snapshots that are often false. How strange that during the period when a person is learning more rapidly than at any other point in his life—when one is learning to walk and talk and make sense of the world—so little of that learning is of the kind that is explicitly memorable.

Freud thought that infantile amnesia was a matter of adults repressing the hypersexualized fantasies of early childhood, which only become shameful in later life. I’m not sure you could find too many psychologists who still cling to that interpretation. The more likely explanation for this strange early forgetting lies in the fact that our brains are maturing rapidly during the first couple years of life, with unused neural connections getting pruned back, and new connections constantly forming. The neocortex is not fully developed until about the third or fourth year, around the time that children start laying down permanent memories. Anatomy, however, may only tell part of the story. As infants, we also lack schema for interpreting the world and relating the present to the past. Without experience—and perhaps most important, without the essential organizing tool of language—infants lack the capacity to embed their memories in a web of meaning that will make them accessible later in life. Those structures only develop over time, through exposure to the world. The vital learning that we do during the first years of life is virtually entirely of the implicit, nondeclarative kind. In other words, everyone on earth has had some taste of EP’s condition. And like EP, we’ve all forgotten what it’s like.

I’m curious to see EP’s unconscious, nondeclarative memory at work, so I ask him if he’s interested in taking me on a walk around his neighborhood. He says, “Not really,” so I wait and ask him again a couple minutes later. This time he agrees. We walk out the front door into the high afternoon sun and turn right—his decision, not mine. I ask EP why we’re not turning to the left instead.

“I’d just rather not go that way. This is just the way I go. I don’t know why,” he says.

If I asked him to draw a map of the route he takes at least three times a day, he’d never be able to do it. He doesn’t even know his own address, or (almost as improbably for someone from San Diego) which way the ocean is. But after so many years of taking the same walk, the journey has etched itself on his unconscious. His wife, Beverly, now lets him go out alone, even though a single wrong turn would leave him completely lost. Sometimes he comes back from his walks with objects he’s picked up along the way: a stack of round stones, a puppy, somebody’s wallet. He can never explain how they came into his possession.

“Our neighbors love him because he’ll come up to them and just start talking to them,” Beverly tells me. Even though he thinks he’s meeting them for the first time, he’s learned through force of habit that these are people he should feel comfortable with, and he interprets those unconscious feelings of comfort as a good reason to stop and say hello.

That EP has learned to like his neighbors without ever learning who they are points to how many of our basic day-to-day actions are guided by implicit values and judgments, independent of declarative memory. I wonder what other things EP has learned through force of habit. What other nondeclarative memories have continued to shape him over the decade and a half since he lost his declarative memory? Surely, he must still have desires and fears, emotions, and cravings—even if his conscious recollection of those feelings is so fleeting that he cannot recognize them for long enough to verbalize them.

I thought of my own self fifteen years ago, and how much I’ve changed in the same period. The me who exists today and the me who existed then, if put side by side, would look more than vaguely similar. But we are a completely different collection of molecules, with different hairlines and waistlines, and, it sometimes seems, little in common besides our names. What binds that me to this me, and allows me to maintain the illusion that there is continuity from moment to moment and year to year, is some relatively stable but gradually evolving thing at the nucleus of my being. Call it a soul, or a self, or an emergent by-product of a neural network, but whatever you want to call it, that element of continuity is entirely dependent on memory.

But even if we are at the mercy of our memories in establishing our identities, it is clear that EP is much more than just a soulless golem. In spite of everything he’s lost, there is still a person there, and a personality—a charming personality, in fact—with a unique perspective on the world. Even if a virus wiped clean his memories, it didn’t completely wipe clean his personhood. It just left a hollow, static self that can never grow and can never change.

We cross the street and walk away from Beverly and Carol, leaving me alone with EP for the first time. He doesn’t know who I am, or what I’m doing at his side, although he seems to sense that I’m there for some good reason. He looks at me and purses his lips, and I can see that he’s searching for something to say. Rather than try to fill the empty silence, I let it linger for a moment to see where the discomfort might lead. I guess I’m hoping for some fleeting recognition of how odd it all must be, this scene without a prologue. But no such recognition comes, or if it does, EP never lets it surface. He is trapped, I realize, in the ultimate existential nightmare, utterly blind to the reality in which he lives. The impulse strikes me to help him escape, at least for a second. I want to take him by the arm and shake him. “You have a rare and debilitating memory disorder,” I want to tell him. “The last fifty years have been lost to you. In less than a minute, you’re going to forget that this conversation ever even happened.” I imagine the horror that would descend upon him, the momentary clarity, the gaping emptiness that would open up in front of him, and close just as quickly. And then the passing car or the singing bird that would snap him back into his oblivious bubble. But of course I don’t do it.

“We’ve gone far enough,” I tell him, and point him in the direction from which we came. We turn around and walk back down the street whose name he’s forgotten, past the waving neighbors he doesn’t recognize, to a home he doesn’t know. In front of the house sits a car with tinted windows. We turn to look at our reflections. I ask EP what he sees.

“An old man,” he says. “That’s all.”