This is a companion piece to Issue #1, in which we discussed the nature of light and the (distressingly quite provable) quantum weirdness of particle/wave duality, which casts doubt on our intuitive preconceptions of reality, and has profound implications for the mental model of the universe typically conjured in the wee brains of we regular folk. If you’ve not read Issue #1, geez, why not? Oh, you must – it’s boffo stuff, here:
Many of the quantum theorists’ most prominent scientific contemporaries, most famously Albert Einstein, but others too, balked at the apparent absurdities that the radical new model forced one to accept, and noted that all you had to do was look around at how things worked in the real world to see that most of it couldn’t possibly be true. On Albert’s side was physicist Erwin Schrödinger, who, contrary to what you might think from only casual exposure to his famous thought experiment involving the cat, was not a big fan of quantum theory, and challenged the assumptions underpinning what’s become known as the “Copenhagen Interpertation”, the experimental evidence for which we discussed last time. To recap briefly, what the experimental results touted by the Quantum Crowd seemed to prove was that at the most fundamental level, the stuff that composed the universe was not, strictly speaking, anything real, and existed only in an amorphous, indeterminate, probabilistic state we lay folk might call “everything-at-once/neither-here-nor-there”, or what the theorists referred to as superposition. Essentially, something we might think of as tangible and measurable in its natural state, like a photon or an electron, was no such thing, but was better thought of as a mere set of probabilities which didn’t actually become what we assumed it had always been until the instant we measured it.
Maybe you need to think about that for a while, roll it around in your mind a bit, to fully grasp just how batshit crazy that is. What the Copenhagen Crew were saying, when you cut through the math and fancy talk, was that nothing really existed until you looked at it. Nothing was independently there, immutable, the way we liked to imagine it. On the contrary, it was only by observing the cloud of possibilities that you forced something in the quantum realm to pick a side, as it were, and resolve down to something that fit our conventional expectations of the Cosmos.
Oh, come on, said Schrödinger, who devised a simple thought experiment to illustrate just how stoned on Absinthe the proponents of the Copenhagen Interpretation had to be. Let’s examine something in the real world, he suggested. A cat, say. Now suppose we put a cat in a sealed box, poor thing, next to a vial of deadly poison. Suppose further that we could rig a mechanism such that the poison would be released, and extinguish the unfortunate kitty, only if something like a radioactive atom emitted a particle. Radioactive elements are unstable, and tend to shed bits of themselves until they can achieve a more stable state, in a process referred to as “decay”. If the Copenhagen Mafia was correct, whether or not an atom could be said to have decayed would depend entirely upon whether we’d taken a look to see, prior to which it both had and hadn’t. It followed, then, that if we rigged the cat-murdering poison to the random occurrence of radioactive decay, which might or might not happen in the time allotted, we could leave kitty in there all day long and the sad little feline would have to exist in there in an indeterminate state, neither alive nor dead, but both. If you believed what the Quantum Nutbar Squad was saying, the logic boxed you into a corner where it wasn’t just that we wouldn’t know whether the cat was dead until we popped the lid. In fact, the cat wouldn’t be dead – or alive either – until we opened the box, at which moment we might find him doing just fine, or stiff as a board. If the latter, the logical implication of quantum theory was that the cat, at the moment of the big reveal, instantly resolved himself into a state of having been been dead for hours and hours, ever since the decay happened – which it both already had and had not, because we hadn’t checked yet, but now that we’ve had a look, yup, sorry Felix, looks like the atom shed a particle earlier this morning. So, then, an action in the present retroactively put an end to a superposition in the past? Either that, or the cat couldn’t possibly be long dead when the box was opened, but of course it could, so how to resolve this paradox within the theory?
Just as an aside, did Schrödinger dislike cats or something? Why not “Schrödinger’s dog”? Or “Schrödinger’s ferret”? Nobody ever asks this.
OK, so right away you can see how this thought experiment proves his point. You and I know perfectly well that it won’t require anybody to take a look in the box to finally determine what state the cat’s been fated to occupy since many hours prior. It already happened, yes? If that atom decayed, it decayed, whether we were looking or not, and the cat either gave up the ghost or it didn’t, one way or another, maybe while we were off having lunch. If the critter bought the farm, we’d know soon enough even without opening the box – the cat corpse would start to rot and stink like a dead skunk in the middle of the road. If there’d been a happier outcome, and kitty was still alive in there, he’d be yowling to get out. Right? So there you go. Case closed. Obviously, things don’t become real only when somebody makes an observation. Reality is reality. If the quantum interpretations of the experiments were correct, why does the cat actually die and start to decompose even if we don’t pop the lid? Eh? Or extrapolate to other real world situations: does anyone really think that a room and its contents dissolve behind us into a mass of quantum indeterminate waves when we leave, and lock up for the night? Really Niels, that’s what you’re selling? As a baffled and somewhat aggravated Einstein asked of the quantum physicists, are you telling me the Moon only exists because a mouse happens to be looking at it?
To which Niels Bohr, Werner Heisenberg et al shrugged, and said you tell me. Who knew? Maybe, even if nobody on the experimental team checked up on the cat, there was somebody or something else that counted as an observer within the laws of nature. Maybe the microbes inside the box. Maybe God. Maybe the cat itself. In a way, they responded to the critiques of Einstein, Schrödinger, and others by throwing up their hands and saying look, we’re not trying to explain why things are the way they are, how it’s even possible, or how to reconcile any of it with what we think we’e perceiving up here in macro-land. We’re just telling you what we can prove. Which they could. Over and over again, oh boy, could they prove it.
It got to the point that Einstein started proposing actual experiments which, if the Quantum Kooks were right, would have to throw off results that were clearly impossible, which therefore wouldn’t happen, and that would finally settle the debate. The Quantum Kooks would then go off and run the experiment, and whaddayaknow, the clearly impossible result would indeed be the outcome. One of these ended up demonstrating quantum entanglement, a topic for another day, which Einstein knew absolutely couldn’t occur because the theoretical result violated relativity. Except it did happen. Every time. No doubt about it. Albert, baffled, began grumbling about “spooky action at a distance”, since the Quantum Mafia seemed to be demonstrating that subatomic particles were somehow communicating with each other instantaneously across time and space, no matter how distant from each other, which seemed to mean that the exchange of information between them was occurring faster than the speed of light. They can’t do that.
They can, though.
What can I tell you? This disconnect between what we see every day and what we can prove occurs down there at the level of atoms and sub-atomic particles is one of the great mysteries of modern science. Physicists are still debating what it means, and whether the Copenhagen Interpretation erroneously accounts for outcomes that can be reconciled with alternative models of reality, some of which don’t require a system composed of waves of probability that only collapse into reality when measured. One of these is the “many worlds” theory proposed by a fellow named Everett, who suggested that waves don’t collapse so much as things bifurcate at the moment of measurement into parallel universes – in which case we’d have one Cosmos in which Schrödinger’s cat is happily alive, and another in which it’s unfortunately stone dead. That’s just super, except: a) it’s an untestable idea, unless somebody comes up with a way to find all these alternate universes, and anything untestable is not a scientific hypothesis; and, b) holy humpin’ horny toads, do you realize how many simultaneous universes an idea like that requires us to posit? Billions, trillions, being generated every second, hell, ever nanosecond, every time a photon so much as hits a leaf.
Maybe Bohr and his pals were wrong to one degree or another. Maybe one day the Copenhagen Interpretation will have to be modified or replaced altogether on the basis of new experimental evidence, though God knows who can come up with the required experiments – thus far, no matter what you try, and how crazy the predictions of quantum theory would seem, you run it and yup, there it is. It’s fine to argue that what’s really happening isn’t what the quantum theorists suggest, but nobody’s been able to prove it, and anyway, any alternative explanation seems likely to be just as crazy-making and intuitively unsatisfactory as wave/particle duality. Inevitable conclusion: the Universe is nuts.
Meanwhile, we rubes in the laity can only sit here, convinced on the basis of everything we see every day that no matter what the propellor-heads claim, that damned table leg was there before I walked barefoot into the room, and didn’t just spring into being because I stubbed my frigging toe on it. Which hurt like hell, the way things do when they’re real.