In his short story “The Garden of Forking Paths,” the Argentinian writer Jorge Luis Borges describes a present that can, at any moment, bifurcate into different futures—an endless labyrinth of worlds. Taken together they form, he writes, “an infinite series of times, a growing, dizzying web of divergent, convergent, and parallel times. That fabric of times that approach one another, fork, are snipped off, or are simply unknown for centuries, contains all possibilities. In most of those times, we do not exist; in some, you exist, but I do not; in others, I do and you do not; in others still, we both do.”
Borges conceived of his garden in 1941, 11 years before the quantum physicist Erwin Schrödinger famously spoke in Dublin about the different results described by his equations and the possibility that parallel universes “be not alternatives but all really happen simultaneously.” It wasn’t until 1957 that the physicist Hugh Everett formally proposed the many-worlds interpretation of quantum physics, a theory that bears a striking resemblance to the forking temporal paths of Borges’s story—and it took more than a decade after that for the scientific community to start taking the idea seriously. (By then, Everett had abandoned further endeavors in theoretical physics. He ultimately drank himself to an early death in the summer of 1982.)
But while present renditions of the quantum multiverse are most often attributed to Everett’s work, they may instead be considered a product of Modernist thought, tracing their source back to the late 19th and early 20th centuries.
Historically, the multiverse was a religious concept, not a physical one—a way to prove God’s existence and benevolence, culminating in the work of the German philosopher and mathematician Gottfried Wilhelm Leibniz. That sentiment is also clear in the portrayal of the multiverse in earlier literature: The many worlds and branching stories of William Blake’s The Four Zoas, written in the late 1700s and early 1800s, for instance, form a multiverse of sorts—but the context is also spiritual in nature.
Schopenhauer turns Leibniz’s argument on its head, proposing we live in “the worst of all possible worlds.”
In fact, the word “multiverse,” first coined in 1895 by American psychologist William James, started as a way to describe human experience—and to, once again, give a reason for putting one’s faith in God. “Visible nature is all plasticity and indifference,” James wrote, “a multiverse, as one might call it, and not a universe.” But this multiverse referred to the overwhelming capriciousness and incomprehensibility posed by Mother Nature: The sum total of our existence in this world, then, is a multiverse; only when imbued with greater meaning can it be reduced to a coherent universe.
“Multiverse” does not mean “many worlds” for James, as it does for physicists, philosophers, and writers today. The modern multiverse is seen as an inevitable result—not a qualitative description or an artificial structure evoked to explain, but rather a consequence of established laws. “These ideas are part of regular physics,” says Andrei Linde, a physicist at Stanford University whose inflationary theory posits that as the universe expands exponentially it gives birth to new universes, making the multiverse as a whole something like an ever-expanding cosmological fractal. “They’re not a part of speculation.” Data, observation, and mathematics steer the way.
The multiverse is a natural outcome of modern philosophy, fiction, and physics. Traces of the idea are already visible in the work of German philosopher Arthur Schopenhauer, who turns Leibniz’s argument for “the best of all possible worlds” on its head by proposing that we instead live in “the worst of all possible worlds.” “For possible means not what we may picture in our imagination, but what can actually exist and last,” Schopenhauer wrote. “Now this world is arranged as it had to be if it were to be capable of continuing with great difficulty to exist; if it were even a little worse, it would be no longer capable of continuing to exist.”
Schopenhauer’s words contain the seed of the anthropic principle, which states that physical properties of the universe—values such as the cosmological constant or the force of gravity, which seem “finely tuned” to meet the needs required for life—must be compatible with the existence of observers who study those properties.
“On or about December 1910,” Virginia Woolf wrote, “human character changed.” And with it, so did the way we tell stories. After the horrors witnessed during World War I, this transformation only deepened. People became disillusioned with the promise of Enlightenment thinking, and the narrative forms that had until then been adequate—those that obeyed the laws of classical mechanics and Newtonian physics—would no longer reflect the reality of modernity. Language could no longer be an accurate means of representing the actual world; narratives were fragmented and disjointed, lacking linear structure (just think of the splintered and stream-of-consciousness styles employed by Woolf, James Joyce, T.S. Eliot); rationality and objectivity were impossible achievements in an absurd universe we could never truly understand.
Readers of the modern novel get lost following references that lead nowhere and spatiotemporal dimensions that make no sense. Textual multiverses arise from the fact that there is no such thing as Truth: They take shape as intertextual labyrinths, as stories within stories, as realities that multiply and proliferate.
Olaf Stapledon, a British philosopher who wrote several influential science-fiction works in the early 20th century (which Borges read and praised), describes a physical proliferation of universes in his 1937 novel Star Maker. The novel follows an unnamed narrator on his disembodied travels through the cosmos, which ultimately lead him to the Star Maker, the creator of the universe—or multiverse, since as it turns out, the narrator’s universe is not alone. Rather, it is one in a series of the Star Maker’s experiments: He began with an aspatial world consisting solely of music, and gradually moved on to more complex creations, the narrator’s universe (and our own) falling somewhere in the middle.
“In one inconceivably complex cosmos,” Stapledon wrote, “whenever a creature was faced with several possible courses of action, it took them all, thereby creating many distinct temporal dimensions and distinct histories of the cosmos. Since in every evolutionary sequence of the cosmos there were very many creatures, and each was constantly faced with many possible courses, and the combinations of all their courses were innumerable, an infinity of distinct universes exfoliated from every moment of every temporal sequence in this cosmos.”
Sound familiar? Both Borges and Stapledon bring us sickeningly close to the infinite. The effect can be disconcerting, bordering on the unpleasant. But since then, it has been revisited time and again, couched in Italo Calvino’s multiform characters and Philip Pullman’s parallel worlds, in C. S. Lewis’s mythology and Philip K. Dick’s alternative histories.
The literary form employed by Stapledon and Borges was, at least in part, informed by the advent of quantum mechanics. Even if the authors were not familiar with the details of quantum theory, they would have known about the revolution taking place in science at the time—particularly the general concepts underlying the measurement problem, Heisenberg’s uncertainty principle, and Schrödinger’s simultaneously-dead-and-alive cat. In any case: Traditional classical mechanics clearly did not provide the whole picture, and the uncertainty at the very foundation of quantum mechanics provided the perfect literary model for modernist ideas.
“In previous physics, if you used Newton’s laws to make a prediction—say, if you used Newton’s law of gravity to predict where Jupiter would be seen in the sky on a certain day—the law also predicts how it got there,” says David Deutsch, a physicist at the University of Oxford. “But in quantum theory, at least in the form it was first invented, consisted of equations where it wasn’t at all clear what happened to bring the results about.” This kind of chaos fell very much in line with the insights Borges and Stapledon wanted to impart after World War I.
And as it turns out, physics may have gotten its multiverse as early as 1927, when Schrödinger was first developing quantum theory, according to Sheldon Goldstein, a professor of mathematics at Rutgers University. In the initial formulation of his theory, which he himself later rejected, Schrödinger sought to interpret his recently-published wave equation as a distribution of matter or charge over space. Given n particles, the wave equation is a function in 3n-dimensional space (since each particle is defined in three dimensions); each point in the space describes a different configuration for those n particles—or, one might say, a different situation for the world. Careful mathematical analysis of how the field taken on that abstract, high-dimensional space relates to the evolution of matter or charge in physical space, in turn, suggests the presence of many worlds.
“It’s pretty subtle,” Goldstein says, “but when you look at it carefully, it seems like you’re dealing with many worlds existing independently in the same space-time.” Think of different kinds of particles that fall into one of two categories, Type 1 or Type 2, he adds. Suppose our world and everything in it, including us, consist of Type 1 particles. But say another world consists of Type 2 particles: It exists in the same space-time, but is an independent reality, one we can never know because it does not interact with our world. “That’s an artificial construction,” Goldstein says, “but in Schrödinger’s case it’s not artificial. You have this dynamic field [on a high-dimensional space] and when you analyze it, you say, wow, it looks like you have particles of Type 1 and Type 2 and Type 3 and so on, each undergoing their own more or less independent histories.”
Schrödinger had dismissed his interpretation because it did not seem to match up with empirical results: After all, it seemed to imply that whenever a scientist experiments, no single outcome obtains; instead, all the outcomes occur at once. That certainly didn’t seem to be happening in the actual world. But this was because Schrödinger’s first theory did not describe a single world at all, Goldstein argues; rather, it was the first scientific many-worlds formulation, arising quite literally from mathematical descriptions of the distribution of matter in space.
Even if Everett did not know of the history behind his idea, the general insights behind it would no doubt have influenced his work. The laws of quantum mechanics, even in the field’s earliest days, led physicists—just as it did authors and philosophers—right into the lap of the multiverse.
Lead image:/ Flickr / MC Escher