I LEARNED about the possibility of the multiverse the same way lots of people did: from William Shatner.

It happened well before I was born, in October 1967. Captain Kirk was in trouble. He and his away team were trying to return to the USS Enterprise from a foreign planet, but a transporter accident causes Kirk and company to materialize on a ship that’s simultaneously the same and different. It’s an “Imperial” rather than “Federation” Starship, and it fights for a brutal, malevolent empire that has somehow replaced Rodenberry’s utopia. Torture substitutes for discipline and crew members ascend in rank by assassinating their superiors; worst of all, First Officer Spock has been replaced with a malevolent counterpart, sporting a neatly-trimmed Van Dyke beard. “It’s our Enterprise, but it isn’t,” Kirk mutters to his crewmates as they seek refuge in the corridors of his ship. “Not our universe, not our ship. Something … parallel. A parallel universe, coexisting with ours, on a parallel plane.” This is not the Enterprise Kirk was looking for.

The idea of the multiverse — a hypothetical set of multiple, even infinite, possible universes — was the territory of science fiction long before Kirk’s transporter accident. We can trace stories of backdoors into alternate dimensions, where the world looks the same but isn’t, back to Edwin Abbot’s seminal (and satirical) 1884 novella Flatland: A Romance in Many Dimensions. (Albert Einstein described a fourth dimension in his general theory of relativity — but he did it some 30 years after Abbot). A decade after Abbot, H.G. Wells appropriated and integrated mathematician Simon Newcomb’s concept of multiple worlds into The Time Machine. Newcomb had thought of time as the fourth dimension of space: “Add a fourth dimension to space,” he wrote, “and there is room for an indefinite number of universes, all alongside of each other, as there is for an indefinite number of sheets of paper when we pile them upon each other.” It’s perhaps appropriate (or, for those more invested in providence, a product of cosmic design) that Wells’s channeling of Newcomb coincided with the introduction of “multiverse” to modern English by William James, who coined the phrase in an 1895 address, grimly proposing that visible nature is “all plasticity and indifference, a multiverse, as one might call it, and not a universe.”

But in the past few decades, popular culture images of the multiverse have been accompanied by a dramatic shift in the actual science. “What is remarkable,” writes Wesleyan University religion professor Mary-Jane Rubenstein in Worlds Without End: The Many Lives of the Multiverse, “is that the ‘multiverse’ has suddenly and dramatically become scientifically thinkable.” The concept can no longer be ignored as a “scientific fantasy”; with innovations in quantum mechanics, string theory, and theoretical physics, the multiverse has become, in Lorraine Daston’s words, a “scientific object.” A century after James cast the natural universe as changing, cruel, and multiple, modern physicists have come to understand the universe as the 40 billion light year radius captured by the Hubble telescope, and the multiverse, as Rubenstein puts it, as “the greater ensemble of unseen worlds.” The theoretical physics underpinning the modern concept of the multiverse — the occurrence of the Big Bang, the existence of “dark matter,” evidence of electromagnetic ripples in space-time that signal the long-ago expansion of the cosmos — tell us that the structure of existence is far from discernable. The infinite is here, and it is much larger, older, and complex than we’ve ever imagined.

So what does the multiverse, that stuff of Star Trek and HG Wells, tell us about the nature of our world? The question isn’t just a scientific one, but a theological one as well. If there are a theoretically infinite number of universes, why do all of nature’s constants seem perfectly suited to allow conscious humans to grow and thrive? And where did all of those variable universes come from? And, on a more fundamental level: why are we here, in the vastness of space and time? “God and dumb luck seem to be the only options,” quips Rubenstein, “and dumb luck is not really an answer.”

But God, Rubenstein knows, isn’t really an answer, either. Physical and religious cosmology — the study of the origins, evolution, structure, and eventual fate of the universe — have enjoyed a complicated relationship for centuries, well before the Hubble telescope allowed humankind to peer into the depths of creation. But how did we get here, from “let there be light” to the multiple worlds we are being taught about by scientists like Alan Guth, Brian Greene, and Martin Rees? This is the question of Rubenstein’s Worlds Without End, which offers readers an intellectual history of the multiverse in “a historical account of the ebbs and flows of multiple-world cosmologies.” If the concept of multiple worlds has enthralled philosophers, mathematicians, and theologians for millennia, what makes the multiverse such an attractive cosmological hypothesis at this specific juncture in human history? And what, if anything, does its resonance mean for how we think about human existence?

The intellectual history of the universe may sound like a daunting topic for those not steeped in experimental physics, but Rubenstein expertly distills millennia of theology, philosophy, and religion into a crisp, engaging exploration. Rubenstein traces the conceptual seeds of the “multiverse” — the belief that space and time are essentially infinite — back to the Ancient Greeks, when cosmology began to challenge the notion of Godly intelligent design as the essential mover of creation. The so-called Atomists of 2500 BCE considered history to be a succession of accidental collisions between tiny units of matter (“atoms”, if you will), colliding and combining in the void of space. Human affairs were subject to the laws of matter and random chance, not the will of some deity, and everywhere and always the outcomes of events might have been otherwise. It’s with the Atomists that we get the first full-throated rejection of theistic creationism: for Lucretius, the Roman poet and philosopher and intellectual godfather of Epicurean atomism, theistic cosmologies aren’t just wrong but “morally treacherous,” giving rise to human conflict rather than offering a resolution to it. God may exist, Lucretius thought, but not at the center of all existence.

In contrast to the Atomists, Rubenstein explains, the Stoic school asserted that there is no such thing as a smallest unit of matter, or atoms. Rather, they followed Aristotle in arguing that matter is continuous, which is to say infinitely divisible. But even as the Stoics asserted the singularity of the cosmos, they rejected the imperishability of the matter that has traditionally secured it. It’s in Stoic cosmology, writes Rubenstein, where Nietzsche found Thus Spoke Zarathustra’s idea of “eternal recurrence”: the idea that the universe is an unconditional and repeated circular course of all things. It’s “Phoenix Theory”, where existence goes through periodic destruction and regeneration.

The cosmic multiplicity proposed by the Atomists and Stoics didn’t last long: the geocentric and heliocentric models of Ptolemy and Copernicus, respectively, enshrined the cosmos (with some difficulty) as singular and finite. And Augustine and Thomas Aquinas, centuries apart, would force many-world cosmologies from the intellectual stage, rejected as threats to the sovereignty of God at the center of Creation. The starkest martyr for the cause of the multiverse was Italian philosopher Giordano Bruno, who was burned alive by the Roman Inquisition just weeks after the turn of the 17th century for claiming the existence of a plurality of eternal worlds. The “allergic reactions” to many-world cosmology, as Rubenstein calls them, only helped to reinforce what eventually became “the usual Western philosophical privileges”: order over chaos, stasis over change, the intelligible over the sensible, the singular over the plural. And it’s the experiences of Bruno and his kin that defined the stark divide between science and theology and left the multiverse in the intellectual backwaters of cosmology for centuries.

But in the early part of the 20th century, the Big Bang and the inflationary model of the universe — the idea that the universe is rapidly expanding — changed all that. Using high-powered telescopes at the South Pole to look back across 13.8 billion years, a team of astronomers just recently detected ripples in the fabric of space-time, the sign of our universe being violently torn apart when it was roughly a trillionth of a trillionth of a trillionth of a second old. Those ripples, as The New York Times recently reported, are the “long-sought smoking-gun evidence” of cosmic inflation first envisioned in the 1980s by Alan Guth. While the “Big Bang” theory of the universe has been the prevailing cosmological model of the universe (and popular culture) since Edwin Hubble observed galaxies receding into the void of space, confirming its inflation would mean that the universe we see is “only an infinitesimal patch in a larger cosmos whose extent, architecture and fate are unknowable,” writes the Times’s Dennis Overbye. “Moreover, beyond our own universe there might be an endless number of other universes bubbling into frothy eternity, like a pot of pasta water boiling over.”

The theoretical physics related to the inflationary model of the universe — the presence of dark matter, the Higgs boson, and their ilk — have turned theology on its head. “Just as it was for the Atomist philosophers in the 5th Century BCE, the multiverse is a way to sidestep theology,” Rubenstein recently told Religion Dispatches. “If there are an infinite number of universes that take on all possible parameters throughout eternity, then we don’t have to appeal to a god to explain the bounty or harmony of the world around us.” In other words, it takes away God’s most significant role in creation through the twin powers of infinity and accident, and replaces intelligent design with an equally baffling article of faith: the actual existence of an infinite number of worlds, eternally generated yet forever inaccessible to us. The multiverse then becomes its own kind of theological postulate, something better than both God and dumb luck combined. “If you don’t want God,” said cosmologist Bernard Carr, “you’d better have a multiverse.”

But where, in this ever-expanding galaxy of cosmology and theoretical physics, do people fit? If the many-worlds interpretation of quantum mechanics has managed to collapse the boundaries between theology and physics, between faith and science, what does the multiverse tell us about livelihood, ethics, and our relationship to time and space? One answer is a rather dreary one. “If your evil twin is out there (which, in an infinite ‘flat’ universe, he or she certainly is), what does it matter what you do in your bit of eternity?” asks science journalist Michael Hanlon in Aeon. “For a half millennium, science has been chipping away at the idea that humanity is central and unique. The multiverse replaces the chisel with a wrecking ball.”

So there’s a faint hint of irony, perhaps, in the fact that the clearest representation of the “modern” scientific multiverse in contemporary culture comes not from science fiction or space opera, but from HBO’s genre-bending crime drama, True Detective. As nihilist savant Rustin Cohle, a mustachioed Matthew McConaughey ponders the emptiness of existence in a Louisiana interrogation room. “You ever heard of something called the M-Brane theory?” asks the disheveled Cohle, sipping beer through his unkempt mustache. Gazing past his inquisitors with a thousand-yard stare, Cohle explains the branch of string theory that posits 11 dimensions of space-time: “It’s like in this universe, we process time linearly forward, but outside of our space-time, from what would be a fourth-dimensional perspective, time wouldn’t exist, and from that vantage, could we attain it, we’d see our space-time would look flattened, like a single sculpture with matter in a superposition of every place it ever occupied, our sentience just cycling through our lives like carts on a track. See, everything outside our dimension that’s eternity, eternity looking down on us. Now, to us, it’s a sphere, but to them it’s a circle.” Cohle’s famed claim that “time is a flat circle” captures our scientific moment, but in it we’re hearing the Stoics whispering from millennia in the past.

How the multiverse has changed; from a narrative playground for the science-driven, optimistic space explorers of Kirk’s Enterprise to the gritty, gruesome, and amoral nothingness of Rust Cohle’s violent world. But this is the beauty of Rubenstein’s deep, nuanced intellectual history: she helps us see that interpretations of a multiverse appearing in Star Trek, or True Detective, or any other work of fiction are only the modern manifestations of the ongoing questions of the universe that have influenced cosmologists, scientists, and theologists for centuries, from the Atomists and Stoics, to Copernicus and Ptolemy, to Nicholas de Cusa and Immanuel Kant. The multiverse is a flat circle: everything old is new again.

In this sense, the theory of the multiverse represents not a closure of life, an infinite, all-consuming maw of meaninglessness, but a reaffirmation of faith, a reimagining of creation through the lens of science. “The endless backs-and-forth over ‘God’s existence’ prevent us from answering the far more interesting questions of what we mean by ‘God,’ and what this idea does in the world,” says Rubenstein. “If by ‘God,’ we mean a Father-figure outside the universe, then there is no way to prove ‘he’ exists or doesn’t exist, precisely because ‘he’ is outside the universe and all our methods of proof are stuck within it. So the more interesting question is how this idea works … What would it mean politically, ethically, and ecologically to say that the cosmo- and biodiversity that constantly brings forth new worlds and forms is what we mean by ‘God’?”

Writing in The New York Times in 2003, English physicist Paul Davies gives voice to the suspicion that modern breakthroughs in theoretical physics may in actuality be bringing that circle of cosmology to a close, with religion and science in conversation with one another. “All cosmologists accept that there are some regions of the universe that lie beyond the reach of our telescopes, but somewhere on the slippery slope between that and the idea that there are an infinite number of universes, credibility reaches a limit,” he muses. “As one slips down that slope, more and more must be accepted on faith, and less and less is open to scientific verification. Extreme multiverse explanations are therefore reminiscent of theological discussions.”

The certainty of the cosmological uncertainty that is the many-worlds interpretation yields an intriguing, almost obvious conclusion: if researchers and scientists explain the structure of the cosmos, why not let your priests and rabbis help you make sense of where you fit into it? “Indeed, invoking an infinity of unseen universes to explain the unusual features of the one we do see is just as ad hoc as invoking an unseen Creator,” writes Davies. “The multiverse theory may be dressed up in scientific language, but in essence it requires the same leap of faith.”

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Jared Keller is a journalist and social media specialist living in Brooklyn, New York.