In “Time Travel,’’ James Gleick has done a wonderful thing. The book delivers on the promise of its title: It dives deep into the science, the philosophy, and the imaginative writings that have explored whether human beings could journey into the future or the past — and what complications would follow if we could.
But this book shouldn’t be mistaken for a work of popular science; this is no “The Physics of Doctor Who.’’ Time-travel enthusiasts will certainly get the history, the basic physics, and a useful tour of the classic paradoxes of time travel and its implications. But the book pursues much greater ambitions as well.
Gleick — a preeminent science author and journalist for over four decades — has long explored some of this territory. Beginning with “Chaos,’’ published in 1987, and through six subsequent books, he’s played with heady ideas about determinism and free will, the pace of time, the physics of time, and more. Now in “Time Travel’’ those themes come to center stage as Gleick asks why, over the long century just past, we have so passionately pursued the idea of an escape from the relentless grip of time.
The book follows a loosely chronological approach, beginning at the moment when, Gleick argues, the concept of time travel first entered the popular imagination. In 1895 the young H. G. Wells published “The Time Machine’’ in which a traveler, equipped with a device that could carry him through what was just beginning to be called the fourth dimension, explored vast reaches of time.
From there Gleick examines what he terms the discovery of the future. That, in his hands, is a history that begins with Gutenberg’s press, an invention that allowed us to preserve “our cultural memory in something visible, tangible, and shareable.” The creation of a record of experience, Gleick argues, enabled people to see the past as different from the present — and imagine that the future might be more than just a repeat of current experience. That grasp of the future as an undiscovered country gained power, he writes, during the Industrial Revolution, to be expressed by “the first true futurist” — Jules Verne — and then, more powerfully by Wells, until, Gleick argues, “[w]e are all futurists now.”
“Time Travel’’ next limns the 20th century scientific revolutions that allowed researchers to ask seriously whether expeditions to the past or future might be possible, beginning in 1905, with Albert Einstein and his discovery that every observer measures his own time, that no two of us share the same moment. “When everything reaching our senses comes from the past,’’ Gleick writes, “when no observer lives in the now of any other observer, the distinction between past and future begins to decay.’’
Writers of speculative fiction eagerly picked up on such developments, even if they didn’t grasp the technical details. There was too much fun to be had: Could you go back and kill your grandfather? What then? How about marrying your mother: Would you become own father?
The book moves through the 20th century in similar, often dazzling moves between science and fiction — both high and low. Jorge Luis Borges published the English version of “The Garden of Forking Paths” in Ellery Queen’s Mystery Magazine and thus anticipated the many-worlds interpretation of quantum mechanics that came 15 years later. That notion in turn has become a staple of those science fictions in which every choice splits the universe into two — one in which, say, Spock is clean shaven, and another in which he rocks a fine goatee.
Gleick has a gift for the resonant line. “If we have only the one universe,” Gleick writes in a passage on the physics of determinism, “then time murders possibility. It erases the lives we might have had.” Sometimes, though, such aphorisms land with a thud, more quips than epiphanies: “What is time? Things change, and time is how we keep track.”
The reader is also occasionally asked to trust an assumption not entirely in evidence — as when Gleick declares that before the invention of clocks, humans experienced time as fluid. The long history of human measurement of time suggests that it was never that simple.
Mostly, though, Gleick leads us on a thrilling journey of ideas. Augustine talks to Robert Heinlein who talks to Kurt Gödel, all the while someone is trying to connect a call between Marcel Proust and the ever patient Sam Beckett. Alongside the big ideas come the odd facts too delicious to leave out, as when we learn that among the audio selections placed on the Voyager spacecraft is the Bulgarian folk song “Izlel je Delyo Hagdutin’’ or “Delyo the Hajduk Has Gone Outside.” Pity the alien trying to decipher that code!
The book ends as Gleick finally answers the question with which he began: “Why do we need time travel?” he asks. “All the answers come down to one. To elude death.”
Writers write, at least in part, to do the same. “Time Travel’’ adds its elegant and witty voice to the unending conversation of book with book. Doing so, it connects the history it documents with the future in which its readers will encounter it.
By James Gleick
Pantheon, 336 pp., illustrated, $26.95Thomas Levenson is a professor of science writing at MIT and the author of several science books. His latest is “The Hunt for Vulcan . . . And How Albert Einstein Destroyed a Planet, Discovered Relativity, and Deciphered the Universe.”