Time Travel. A History

The universe just doesn’t put up with that. We aren’t important enough….There are too many factors, too many variables. Time isn’t an orderly stream. Time isn’t a placid lake recording each of our ripples. Time is viscous. Time is a massive flow. It is a self-healing substance, which is to say, almost everything will be lost.

Charles has learned some more rules. If you ever see yourself coming out of a time machine, run the other way as fast as you can. Nothing good can come of meeting yourself. Try not to have sex with anyone who could possibly be a relative. (“One guy I know ended up as his own sister.”) This is twenty-first-century metanarrative: loopy, recursive, self-referential to the nth degree. Real science (“real” science) mixes with science-fictional science, which is both a parody of real science and a real science of science fiction. If you see what I mean. Example: “A character within a story, or even a narrator, has, in general, no way of knowing whether or not he is in the past tense narration of a story, or is instead in the present tense (or some other tensed state of affairs) and merely reflecting upon the past.”

Above all he misses his father—the father who taught him everything about time travel, who used to say things like, “Today we will journey into Minkowski space,” whom he reveres and loves in his memory. So much of time travel is a search for parents, when you think about it. In the Back to the Future movies, Marty McFly needs to discover his parents’ pasts. His destiny is there. For that matter, the Terminator movies are all about finding (killing, protecting) the mother, though the characters don’t talk as much about their feelings. “Who wouldn’t want to travel back in time and encounter their parents before they become their parents?” asks William Boyd in his 2015 novel Sweet Caress. “Before ‘mother’ and ‘father’ turned them into figures of domestic myth.” We experience childhood one way when we’re living it and another way when we relive it in memory. And when we become parents ourselves, we may rediscover our own parents and our own childhoods, as if for the first time. That’s the closest we get to having a time machine.

“How can we tell present from past?” Charles’s father says this is the key question of time travel. “How do we move the infinitesimal window of the present through the viewfinder at such a constant rate?” It may also be the key question of consciousness. How do we construct the self? Can there be memory without consciousness? Obviously not. Or obviously. It depends what you mean by memory. A rat learns to run a maze—does it remember the maze? If memory is the perpetuation of information, then the least conscious of organisms possess it. So do computers, whose memory we measure in bytes. So does a gravestone. But if memory is the action of recollection, the act of remembrance, then it implies an ability to hold in the mind two constructs, one representing the present and another representing the past, and to compare them, one against the other. How did we learn to distinguish memory from experience? When something misfires and we experience the present as if it were a memory, we call that déjà vu. Considering déjà vu—an illusion or pathology—we might marvel at the ordinary business of remembering.

Can there be consciousness without memory? “We are our memory,” said Borges,

we are that chimerical museum of shifting shapes,

that pile of broken mirrors.

Our conscious brains invent the concept of time over and over again, inferring it from memory and extrapolating from change. And time is indispensable to our awareness of self. Just as an author does, we construct our own narrative, assemble the scenes in a plausible order, make inferences about cause and effect. Charles’s software companion explains, “The book, just like the concept of the ‘present,’ is a fiction. Which isn’t to say it’s not real. It’s as real as anything else in this science-fictional universe. As real as you are. It’s a staircase in a house built by the construction firm of Escher and Sons.”

You order the slices of your life. You edit the film even as it records. “Your brain has to trick itself to live in time,” she says. Time travel adds a high-octane upgrade to the usual process of creating consciousness.

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A HUNDRED YEARS EARLIER, when storytelling seemed simpler and E. M. Forster thought every novel embodied a clock, he invented a story about the future. “Imagine, if you can,” he wrote in 1909, “a small room, hexagonal in shape.” At its center rests an armchair. In the armchair sits a woman—“a swaddled lump of flesh…with a face as white as a fungus.” She is happily incarcerated, with every modern comfort: