What do we learn about science from a controversy in physics?
By Adam Gopnik /The New Yorker/Blogger Ref http://www.p2pfoundation.net/Multi-Dimensional_Science
What makes science science? The pious answers are: its ceaseless curiosity in the face of mystery, its keen edge of experimental objectivity, its endless accumulation of new data, and the cool machines it uses. We stare, the scientists see; we gawk, they gaze. We guess; they know.
But there are revisionist scholars who question the role of scientists as magi. Think how much we take on faith, even with those wonders of science that seem open to the non-specialist’s eye. The proliferation of hominids—all those near-men and proto-men and half-apes found in the fossil record, exactly as Darwin predicted—rests on the interpretation of a few blackened Serengeti mandibles that it would take a lifetime’s training to really evaluate. (And those who have put in the time end up squabbling anyway.)
Worse, small hints of what seems like scamming reach even us believers. Every few weeks or so, in the Science Times, we find out that some basic question of the universe has now been answered—but why, we wonder, weren’t we told about the puzzle until after it was solved? Results announced as certain turn out to be hard to replicate. Triumphs look retrospectively engineered. This has led revisionist historians and philosophers to suggest that science is a kind of scam—a socially agreed-on fiction no more empirically grounded than any other socially agreed-on fiction, a faith like any other (as the defenders of faiths like any other like to say). Back when, people looked at old teeth and broken bones with the eye of faith and called them relics; we look at them with the eye of another faith and call them proof. What’s different?
The defense of science against this claim turns out to be complicated, for the simple reason that, as a social activity, science is vulnerable to all the comedy inherent in any social activity: group thinking, self-pleasing, and running down the competition in order to get the customer’s (or, in this case, the government’s) cash. Books about the history of science should therefore be about both science and scientists, about the things they found and the way they found them. A good science writer has to show us the fallible men and women who made the theory, and then show us why, after the human foibles are boiled off, the theory remains reliable.
No well-tested scientific concept is more astonishing than the one that gives its name to a new book by the Scientific American contributing editor George Musser, “Spooky Action at a Distance” (Scientific American/Farrar, Straus & Giroux). The ostensible subject is the mechanics of quantum entanglement; the actual subject is the entanglement of its observers. Musser presents the hard-to-grasp physics of “non-locality,” and his question isn’t so much how this weird thing can be true as why, given that this weird thing had been known about for so long, so many scientists were so reluctant to confront it. What keeps a scientific truth from spreading?
The story dates to the early decades of quantum theory, in the nineteen-twenties and thirties, when Albert Einstein was holding out against the “probabilistic” views about the identity of particles and waves held by a younger generation of theoretical physicists. He created what he thought of as a reductio ad absurdum. Suppose, he said, that particles like photons and electrons really do act like waves, as the new interpretations insisted, and that, as they also insisted, their properties can be determined only as they are being measured. Then, he pointed out, something else would have to be true: particles that were part of a single wave function would be permanently “entangled,” no matter how far from each other they migrated. If you have a box full of photons governed by one wave function, and one escapes, the escapee remains entangled in the fate of the particles it left behind—like the outer edges of the ripples spreading from a pebble thrown into a pond. An entangled particle, measured here in the Milky Way, would have to show the same spin—or the opposite spin, depending—or momentum as its partner, conjoined millions of light-years away, when measured at the same time. Like Paul Simon and Art Garfunkel, no matter how far they spread apart they would still be helplessly conjoined. Einstein’s point was that such a phenomenon could only mean that the particles were somehow communicating with each other instantaneously, at a speed faster than light, violating the laws of nature. This was what he condemned as “spooky action at a distance.”
John Donne, thou shouldst be living at this hour! One can only imagine what the science-loving Metaphysical poet would have made of a metaphor that had two lovers spinning in unison no matter how far apart they were. But Musser has a nice, if less exalted, analogy for the event: it is as if two magic coins, flipped at different corners of the cosmos, always came up heads or tails together. (The spooky action takes place only in the context of simultaneous measurement. The particles share states, but they don’t send signals.)
What started out as a reductio ad absurdum became proof that the cosmos is in certain ways absurd. What began as a bug became a feature and is now a fact. Musser takes us into the lab of the Colgate professor Enrique Galvez, who has constructed a simple apparatus that allows him to entangle photons and then show that “the photons are behaving like a pair of magic coins. . . .They are not in contact, and no known force links them, yet they act as one.” With near-quantum serendipity, the publication of Musser’s book has coincided with news of another breakthrough experiment, in which scientists at Delft University measured two hundred and forty-five pairs of entangled electrons and confirmed the phenomenon with greater rigor than before. The certainty that spooky action at a distance takes place, Musser says, challenges the very notion of “locality,” our intuitive sense that some stuff happens only here, and some stuff over there. What’s happening isn’t really spooky action at a distance; it’s spooky distance, revealed through an action.
Why, then, did Einstein’s question get excluded for so long from reputable theoretical physics? The reasons, unfolding through generations of physicists, have several notable social aspects, worthy of Trollope’s studies of how private feuds affect public decisions. Musser tells us that fashion, temperament, zeitgeist, and sheer tenacity affected the debate, along with evidence and argument. The “indeterminacy” of the atom was, for younger European physicists, “a lesson of modernity, an antidote to a misplaced Enlightenment trust in reason, which German intellectuals in the 1920’s widely held responsible for their country’s defeat in the First World War.” The tonal and temperamental difference between the scientists was as great as the evidence they called on.
Musser tracks the action at the “Solvay” meetings, scientific conferences held at an institute in Brussels in the twenties. (Ernest Solvay was a rich Belgian chemist with a taste for high science.) Einstein and Niels Bohr met and argued over breakfast and dinner there, talking past each other more than to each other. Musser writes, “Bohr punted on Einstein’s central concern about links between distant locations in space,” preferring to focus on the disputes about probability and randomness in nature. As Musser says, the “indeterminacy” questions of whether what you measured was actually indefinite or just unknowable until you measured it was an important point, but not this important point.
Musser explains that the big issue was settled mainly by being pushed aside. Generational imperatives trumped evidentiary ones. The things that made Einstein the lovable genius of popular imagination were also the things that made him an easy object of condescension. The hot younger theorists patronized him, one of Bohr’s colleagues sneering that if a student had raised Einstein’s objections “I would have considered him quite intelligent and promising.”
There was never a decisive debate, never a hallowed crucial experiment, never even a winning argument to settle the case, with one physicist admitting, “Most physicists (including me) accept that Bohr won the debate, although like most physicists I am hard pressed to put into words just how it was done.” Arguing about non-locality went out of fashion, in this account, almost the way “Rock Around the Clock” displaced Sinatra from the top of the charts.
The same pattern of avoidance and talking-past and taking on the temper of the times turns up in the contemporary science that has returned to the possibility of non-locality. Musser notes that Geoffrey Chew’s attack on the notion of underlying laws in physics “was radical, and radicalism went over well in ’60’s-era Berkeley.” The British mathematician Roger Penrose’s assaults on string theory in the nineties were intriguing but too intemperate and too inconclusive for the room: “Penrose didn’t help his cause with his outspoken skepticism. . . . Valid though his critiques might have been, they weren’t calculated to endear him to his colleagues.”
Indeed, Musser, though committed to empirical explanation, suggests that the revival of “non-locality” as a topic in physics may be due to our finding the metaphor of non-locality ever more palatable: “Modern communications technology may not technically be non-local but it sure feels that it is.” Living among distant connections, where what happens in Bangalore happens in Boston, we are more receptive to the idea of such a strange order in the universe. Musser sums it up in an enviable aphorism: “If poetry is emotion recollected in tranquility, then science is tranquility recollected in emotion.” The seemingly neutral order of the natural world becomes the sounding board for every passionate feeling the physicist possesses.
Is science, then, a club like any other, with fetishes and fashions, with schemers, dreamers, and blackballed applicants? Is there a real demarcation to be made between science and every other kind of social activity? One of Musser’s themes is that the boundary between inexplicable-seeming magical actions and explicable physical phenomena is a fuzzy one. The lunar theory of tides is an instance. Galileo’s objection to it was like Einstein’s to the quantum theory: that the moon working an occult influence on the oceans was obviously magical nonsense. This objection became Newton’s point: occult influences could be understood soberly and would explain the movement of the stars and planets. What was magic became mathematical and then mundane. “Magical” explanations, like spooky action, are constantly being revived and rebuffed, until, at last, they are reinterpreted and accepted. Instead of a neat line between science and magic, then, we see a jumpy, shifting boundary that keeps getting redrawn. It’s like the “Looney Tunes” cartoon where Bugs draws a line in the dirt and dares Yosemite Sam to “just cross over dis line”—and then, when Sam does, Bugs redraws it, over and over, ever backward, until, in the end, Sam steps over a cliff. Real-world demarcations between science and magic, Musser’s story suggests, are like Bugs’s: made on the move and as much a trap as a teaching aid.
In the past several decades, certainly, the old lines between the history of astrology and astronomy, and between alchemy and chemistry, have been blurred; historians of the scientific revolution no longer insist on a clean break between science and earlier forms of magic. Where once logical criteria between science and non-science (or pseudo-science) were sought and taken seriously—Karl Popper’s criterion of “falsifiability” was perhaps the most famous, insisting that a sound theory could, in principle, be proved wrong by one test or another—many historians and philosophers of science have come to think that this is a naïve view of how the scientific enterprise actually works. They see a muddle of coercion, old magical ideas, occasional experiment, hushed-up failures—all coming together in a social practice that gets results but rarely follows a definable logic.
Yet the old notion of a scientific revolution that was really a revolution is regaining some credibility. David Wootton, in his new, encyclopedic history, “The Invention of Science” (Harper), recognizes the blurred lines between magic and science but insists that the revolution lay in the public nature of the new approach. “What killed alchemy was not experimentation,” he writes. He goes on:
What killed alchemy was the insistence that experiments must be openly reported in publications which presented a clear account of what had happened, and they must then be replicated, preferably before independent witnesses. The alchemists had pursued a secret learning, convinced that only a few were fit to have knowledge of divine secrets and that the social order would collapse if gold ceased to be in short supply. . . . Esoteric knowledge was replaced by a new form of knowledge, which depended both on publication and on public or semi-public performance. A closed society was replaced by an open one.
In a piquant way, Wootton, while making little of Popper’s criterion of falsifiability, makes it up to him by borrowing a criterion from his political philosophy. Scientific societies are open societies. One day the lunar tides are occult, the next day they are science, and what changes is the way in which we choose to talk about them.
Wootton also insists, against the grain of contemporary academia, that single observed facts, what he calls “killer facts,” really did polish off antique authorities. Facts are not themselves obvious: the fact of the fact had to be invented, litigated, and re-litigated. But, once we agree that the facts are facts, they can do amazing work. Traditional Ptolemaic astronomy, in place for more than a millennium, was destroyed by what Galileo discovered about the phases of Venus. That killer fact “serves as a single, solid, and strong argument to establish its revolution around the Sun, such that no room whatsoever remains for doubt,” Galileo wrote, and Wootton adds, “No one was so foolish as to dispute these claims.” Observation was theory-soaked—Wootton shows a delightful drawing of a crater on the moon that does not actually exist, drawn by a dutiful English astronomer who had just been reading Galileo—and facts were, as always, tempered by our desires. But there they were, all the same, smiling fiendishly, like cartoon barracudas, as they ate up old orbits.
Several things flow from Wootton’s view. One is that “group think” in the sciences is often true think. Science has always been made in a cloud of social networks. But this power of assent is valuable only if there’s a willingness to look a killer fact in the eye. The Harvard theoretical physicist Lisa Randall’s new book, “Dark Matter and the Dinosaurs” (Ecco), has as its arresting central thesis the idea that a disk of dark matter might exist in the Milky Way, perturbing the orbits of comets and potentially sending them periodically toward Earth, where they are likely to produce large craters and extinctions. But the theory is plausible only because a single killer fact murdered an earlier theory—which held that an unseen star was out there, doing the perturbing and the extincting. Every newer orbiting telescope has scanned the skies, and the so-called Nemesis star hasn’t shown up. Disks of dark matter can now appear in the space left empty by the star’s absence.
A similar pattern is apparent in the case of the search for “Vulcan,” the hypothesized planet that, in the nineteenth century, sat between Mercury and the sun and explained perturbations in Mercury’s orbit. As Thomas Levenson explains in “The Hunt for Vulcan” (Random House), nineteenth-century astronomers were so in love with the idea of the missing planet that many of them, bewitched by random shadows, insisted they had seen it through their telescopes. Only in 1915, when Einstein emerged with a new interpretation of the perturbations (something to do with gravity as space-time curvature), could astronomers stop “seeing” what wasn’t there.
There has been much talk in the pop-sci world of “memes”—ideas that somehow manage to replicate themselves in our heads. But perhaps the real memes are not ideas or tunes or artifacts but ways of making them—habits of mind rather than products of mind. Science isn’t a slot machine, where you drop in facts and get out truths. But it is a special kind of social activity, one where lots of different human traits—obstinacy, curiosity, resentment of authority, sheer cussedness, and a grudging readiness to submit pet notions to popular scrutiny—end by producing reliable knowledge. The spread of Bill James’s ideas on baseball, from mimeographed sheets to the front offices of the Red Sox, is a nice instance of how a scientific turn of mind spread to a place where science hadn’t usually gone. (James himself knew it, remarking that if he was going to be Galileo someone had to be the Pope.)
One way or another, science really happens. The claim that basic research is valuable because it leads to applied technology may be true but perhaps is not at the heart of the social use of the enterprise. The way scientists do think makes us aware of how we can think. Samuel Johnson said that a performer riding on three horses may not accomplish anything, but he increases our respect for the faculties of man. The scientists who show that nature rides three horses at once—or even two horses, on opposite sides of the universe—also widen our respect for what we are capable of imagining, and it is this action, at its own spooky distance, that really entangles our minds. ♦
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