life— who made those random choices.
It was not a new idea. Many researchers had already bandied about the
notion of replacing machines with humans. But nobody could figure out
how to make it work. The problem was that people were not fast enough.
They were capable of making choices only so often— a few times per second, maybe. But the experiments needed to flip their analyzers’ orientations at lightening speeds.
Abellán’s wonderful idea was to circumvent this limitation by using
large numbers of people. How to get in touch with them? Use social media.
And how to persuade them to make those random choices? Lure them in.
Invent something so attractive, so seductive and enticing, that vast numbers of people would be sucked into the project. How to do this? By inventing
a game.
It would be an online game. The researchers would create a network of
players, a vast agglomeration encompassing huge numbers of people from
across the globe, all playing the game at the very same time and each one of them making random choices. Out of this network of players an immense
storehouse of pure chance would accumulate. Accumulate, and drive the
course of experiments testing Bell’s Theorem.
They called their game “the BIG Bell Test.” It lived on a website.a
The test would ask people to make choices. It was actually very simple,
if truth be told: all a player had to do was enter a series of 0’s and 1’s into a smartphone. The hard part was that this had to be done randomly and
rapidly.
a. You can play this game yourself. See https://museum.thebigbelltest.org/#/home?
l=EN
Experimental … 89
The experimenters built into their app all the elements of modern gaming:
trendy animations and sound effects to cheer the gamers on their way, leaderboards, boss battles and power ups, the opportunity to form groups and compare their skill levels with those of fellow gamers. From time to time players would be reminded that their inputs were being used in actual experiments
underway at that very moment in laboratories across the globe. And as they refined their skills and graduated from one level of the game to the next, they might be rewarded with some interesting tidbit about the mathematics
of randomness, or by a prerecorded video from one of the experiments.
Meanwhile the Oracle would be watching.
The Oracle’s function was to tell the players how well they were doing—
how much randomness they were achieving. For it turns out that it is not
so easy to be random. Suppose for instance that, as you madly typed away,
you just happened to enter three 0’s in a row. Studies have shown that in
such a situation you are more likely to avoid 0 for your fourth step and
enter a 1 instead. This in spite of the fact that true randomness dictates that you should be equally likely to choose either. The Oracle was a “prediction engine” that studied your previous entries and tried to anticipate your next: if it succeeded, this was proof that you were not achieving true randomness. And the Oracle would tell you so. The Oracle was the enemy against which you were competing.
Having built their game, the next step was to recruit the players. (They
called them “Bellsters.”) A massive advertising campaign was launched— on
social media, in newspapers and TV ads and announcements to schools and
science museums. More than 230 headlines resulted. The game and accompanying information were made available on the group’s website in seven languages, making it accessible to over three billion people: that is nearly half the world’s population.
Of course, all this was only the first step. What about the experiments
that would use the data? The members of Mitchell’s group were planning
to run their own experiment. But they wanted others. They advertised their project to laboratories across the world, and ultimately assembled a group of researchers running fully 13 different experiments. They were situated in nations spanning the globe: Barcelona, China, the United States …
Everything would happen at the same time: experiments running, Bellsters gaming. The whole thing was a massive exercise in organization. Gaming day was set for November 30, 2016.
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Across the spinning globe daylight dawned. The experiments fired up
and got ready for the data. Meanwhile, the gamers got busy. They came
from most of the nations of the world: from Europe and the Americas, from
China, Australia— there were even some from Antarctica. Over the course
of the next 51 hours some 100,000 gamers entered their data: more than 97
million 0’s and 1’s. Over one 12 hour period the worldwide group reached
and sustained a rate of 1,000 random choices per second.
The 13 experiments, all running at the same time, used these data to
test Bell’s Theorem. Every one of them found that quantum mechanics was
valid and hidden variables were not.
It all rests on a conundrum, of course. For is it really true that we have free will? Were the gamers actually behaving randomly? I think it is fair to say that our brains are machines. and so cannot be truly random. But a brain—
the actual, physical object lying between our ears— is one thing, and a mind is another. Is it possible for our brains to be deterministic while at the same time we humans are not? As for myself, I have no idea.
So we can make of this project what we will. Perhaps it adds a vital element to the situation and perhaps not. But no matter: it was a wonderful project—
wonderful for the gamers and, I am willing to bet, for the scientists too.
Nowadays many groups of experimentalists are hard at work, closing loophole after loophole. There are certainly enough of them to be closed. Why only last week I came across an article listing fully ten. The task of closing all these loopholes is not yet complete. Indeed, it is not even a matter of closing first one and then another: best of all would be to close them all at once. So it’s a slow process.
But perhaps you feel that all this effort is just a little bit silly. After all—
aren’t these physicists being maybe just a little bit paranoid? Are they
perhaps starting to resemble some bunch of conspiracy theorists, hard at
work inventing one nutty idea after another? Who could possibly take
seriously the notions of “phone calls between particles” or “preordaining
influences”— notions without the slightest thing to recommend them
beyond my lame assertion that “maybe it is possible after all”?
I’ll tell you who would do all this: anybody who wants to be sure about
quantum theory— very sure, as sure as humanly possible about one of the
most important scientific discoveries of all time.
Experimental … 91
Scientists want their knowledge to be trustworthy. All of us want our
knowledge to be trustworthy. So much of life is uncertain. We want as much certainty as we can get. We want to be able to trust what little we do know.
I like to think in terms of the analogy of climbing a ladder. Suppose you
have propped a ladder up against a wall— a long ladder, one that will carry you way up into the heights. Would you be willing to start up that ladder
before making sure it is secure? As for me, I certainly wouldn’t. I would
shake it, swing it to and fro.
In doing so, my goal is not to knock the ladder down. It is to make sure
that nothing else can knock it down. That’s what these loophole chasers are doing. They are “shaking” quantum mechanics in every way they can. They
are probing f
or weaknesses in all the various experiments that purport to
confirm the theory— all in order to make sure that the experiments are trustworthy. And the results to date have shown that the ladder that is quantum mechanics is utterly trustworthy.
But I would not want to leave it at that. For in truth I believe that there is a further reason these people are spending so much time and effort on all these beautiful experiments. It is that the experiments really are beautiful.
It is that only now, now that the latest and sexiest gadget is available from that high tech corporation in Texas; and only now that those colleagues
down the hall have invented yet another brilliant technique for doing yet
another new thing— only now has it suddenly become possible to do what
yesterday was impossible. So you get down to cases and you do do it.
I love that about science: that great, windblown sense of openness about
the whole enterprise.
13 … Metaphysics
Clauser was not happy with the result of his experiment. He had been
thinking that his gadget would yield the opposite conclusion. Indeed,
he once told me that he had been so sure of things that he was willing to
place a bet that quantum mechanics would turn out to be wrong. Two to
one odds were the best that a colleague would give him, and he accepted
them. Unfortunately— or fortunately, if you prefer— Clauser lost the bet.
He mailed off a two dollar bill to his colleague: so far as he knows, that colleague still has it up on his office wall.
After all, Clauser had wanted to discredit quantum theory.
I was convinced that quantum mechanics had to be wrong. … I kept saying,
“Well, we did the experiment, what could be wrong?” Obviously we got the
“wrong” result. I had no choice but to report what we saw— You know, here’s the result. But it contradicts what I believed in my gut has to be true. The result, I didn’t expect. I hoped we would overthrow quantum mechanics.1
But it was not just a matter of youthful rebelliousness. It was not just a matter of wanting to overthrow a cherished theory. It was also a matter of having to figure out what his experiment was telling us.
Quantum mechanics predicts the impossible— we have known that for
decades. But what Clauser’s and Aspect’s and all the other metaphysical
experiments are telling us that the real world accomplishes the impossible. And how can that be? What have we learned from all the experiments testing Bell’s Theorem? Nature violates Bell’s restriction: what does this astonishing result tell us?
The question is hard to answer in any simple way, and there is no agreement among workers in the field. We are still sorting it all out.
One possible conclusion to be drawn is that there are no hidden variables. There is no real physical situation, no actual state of affairs. If this is
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so, it means that my Great Predictor is silent for a reason: that there is simply nothing to be said more than what he does say. It also means that quantum
mechanics is not a half theory at all, but a full theory, a theory perfectly suited to the strange new world on which we have inadvertently stumbled.
This conclusion is not airtight, for it rests on an assumption— the so
called “locality” assumption— which I will discuss later. But for now, let us ask what it could possibly mean.
It means that particles in the quantum realm do not possess certain
properties. But I would argue that properties are essential for our thinking.
They are built into the very way our minds work. How could we think of an
electron spinning but not spinning in a definite direction? How might we
imagine a particle with not zero speed, not with this speed or that speed, but with no particular speed … but nevertheless produced at a certain
moment at a certain place, and detected a certain amount of time later a
certain distance away? How could we hold in our mind’s eye the image of a
thing without a location? It all seems like a very violation of logic.
It is not like forgetting where you parked the car. You think that the car might be on this street or that street— but imbedded in this way of thinking is the conviction that the car is somewhere, at a place that exists but that you do not happen to recall. This is different. This would be a car without the property of location. Without location until you find the car, at which point its whereabouts become entirely real.
To say that hidden variables do not exist is to call into question the very meaning of what we mean by a thing. For surely, things have properties, and these properties have consequences. Consider:
• A living room has an open window. Stand inside the room, and toss a
ball in some random direction. Does the ball make it through the window, or clatter against the wall and remain inside? The property that determines the outcome is the direction the ball is moving. That property is a variable: if the lights are out and you can’t see the ball, it is a hidden variable.
• A ray of light is approaching a piece of red transparent glass. If the light is red it gets through the glass: if it isn’t, it is blocked. The property that determines whether the ray passes through the glass is its color.
• A woman is approaching a bar. On the door there is a sign: “No one under 18 admitted.” The property determining whether she gets in is her age.
… Metaphysics 95
• In chapter 2 I gave an analogy to radioactive decay: the analogy of a
maple tree in autumn. Some of the leaves fall sooner than others. But
why? When I questioned the Great Predictor, asking for the reason, he
would not answer. And now we know why he so adamantly refused to
speak: because there was no reason. A “reason,” after all, is a hidden variable … and hidden variables do not exist.
• An electron is approaching a detector oriented along the vertical direction. Will the detector find “up” or “down?” Here apparently there is no property belonging to the electron that determines what the detector
does. But nevertheless, the detector does something.
In many ways, electrons seem quite ordinary. An electron can be
produced— by an electron gun, say— at a certain place and time. It can be
detected— by the screen on a TV set, say— at another place and time. An electron has a perfectly definite mass and electric charge and magnitude of spin.
All this makes us think of an electron as being a thing in the ordinary sense of the term: sort of a tiny pebble. But nobody has ever seen an
electron— their presence is only inferred indirectly— and maybe we are a
little hasty in treating them so cavalierly. For consider good news. Good news can be produced at a certain time and place, it can be detected by a person at some other time and place, it has an effect on that person, and it travels quite rapidly. Nevertheless, nobody would think of it as a thing. Maybe an electron is more like news, and not so much like a pebble.
But it is only certain properties that the electron does not possess. The particle has a perfectly definite mass and charge, for instance. Furthermore, it is not only electrons that we are speaking of here: photons, neutrons,
atoms … every denizen of the microworld partakes of the same enigmatic quantum nature.
There are times when I think that what we really need is a new terminology. We speak of particles as things. We say that some thing left the electron gun and arrived at the detector. But when we speak in these terms, we are
naturally led to ask all sorts of questions about these particles. Why can’t we see them, for instance? And what shape are they— spheres, cubes, or
perhaps shaped like some Chinese ideogram? What is their color? Are they
>
cheerful or gloomy, sweet smelling or acrid? Carrying on in this way, we
can be easily led astray— led astray by the set of unconscious associations that the word “thing” raises within our minds. Our language forces on us a certain way of thinking, a way that apparently we must be careful to resist.
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Every time a quantum particle enters a detector, the detector responds
by doing something. Maybe it tells us that the particle’s spin is along some direction. Maybe it tells us that the particle is over there. Maybe it tells us that the particle is zipping along at such and such a velocity. But what do these responses mean? A measurement is supposed to reveal a property
of the thing studied— a thermometer tells us the temperature of the air, a barometer its pressure. These are not matters of opinion, not matters of taste, but facts: real properties of a real world. But if there is anything we have learned so far, it is that the microworld is different. We used to think that a particle has a spin that points in some direction, that it is at some place, and that it is moving with some speed. And we used to think that the detector
has merely found out these properties. But now … well, now we had better
be careful.
Because if things do not have these properties, then what has a measurement told us?
Quantum theory has an answer to this question. The answer is that a
measurement does not reveal a property of the microworld: rather, the measurement creates that property. Prior to the measurement the electron spin had no particular direction: after the measurement it does.
That is a gigantic shift in thinking. Do you like that shift? Is it congenial to you? Read what the brilliant physicist E. T. Jaynes has to say about it: From this, it is pretty clear why present quantum theory not only does not use— it does not even dare to mention— the notion of a “real physical situation.” Defenders of the theory say that this notion is philosophically naïve, a throwback to outmoded ways of thinking, and that recognition of this constitutes deep new wisdom about the nature of human knowledge. I say that it constitutes a violent irrationality, that somewhere in this theory the distinction between reality and our knowledge of reality has become lost, and the result has more the character of medieval necromancy than of science.2
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