The Grandfather Paradox: Experimentally Resolved?
A revised and improved version of this essay is in my book Sci-Ence! Justice Leak! – hardback, paperback, PDF
I am utterly astounded that I’d never seen this before today – an experiment that may have more profound implications for our worldview than… maybe any experiment since the Michelson-Morley experiment?
I’m going to assume here that everyone knows about the Grandfather Paradox. This is just the simple question “What happens if you have a time machine, and go back and kill your granddad so you can never be born?”, the staple of many TV science fiction shows.
Now the normal answer to that question is “You can’t, so don’t be daft”. But for physicists, that’s not good enough – apart from anything else, General Relativity allows for the existence of ‘closed timelike curves’. These are paths through space-time that act much like paths through space – you can go in at one end and pop out the other – except that the other end is somewhere else in time as well as space. So it’s theoretically possible that you *could* do that, and we’d quite like to know what would happen if you did before everyone’s granddad starts retroactively never-having-existed.
Now, the main hypothesis in physics up to now has been, in effect, that it doesn’t matter. David Deutsch, a quantum computing expert at Oxford University, demonstrated that in quantum-mechanical terms you could have an outcome that makes sense so long as you accepted the many-worlds version of reality. Essentially, the probability that you were ever born, and the probability that you killed your grandfather, would both be 1/2 – or in other words the ‘you’ in a universe where you were born would travel to a universe where you were never born, kill your grandfather there, then come back to one where you’d never killed your grandfather. Nice and simple.
However, Seth Lloyd, a quantum physicist at MIT, never liked the many-worlds hypothesis (for reasons which, I have to say, make no sense at all to me), and he and a team of colleagues came up with another, simpler, idea, which is just that if you go back in time and try to shoot your grandfather, something will stop you. Maybe the gun will misfire, maybe you’ll be arrested, maybe your grandma was having an affair with the milkman and you’re his biological grandchild – something will just make sure that you can’t do that, because it would be cheating.
Now, there are huge, huge, MASSIVE problems with this – it gets rid of causality, it allows information to come from nowhere, and it just seems like a gigantic handwave. It makes no sense at all, and just seems like a desperate attempt to try to get out of the obvious, blatant, truth that the Many-Worlds interpretation is the only one consistent with the experiments and maths. When I first read about it, I thought it was just a neat way of avoiding the truth.
Unfortunately, it appears to be true. What I hadn’t realised was that they’d *actually done the experiment*!
Lloyd and his colleagues came up with an ingenious experiment, which I’m not entirely sure I’m capable of explaining, as it’s not really sunk in yet. This will be a GROSS oversimplification, and is just designed to get the idea across – please don’t kill me for inaccuracies. The full description is in the linked PDF. This is what Pratchett, Stewart and Cohen call lies-to-adults – the story is right, but each individual fact is wrong.
Essentially, photons (light particles) can be polarised a couple of ways, and they’ll only go through stuff that’s polarised the same way. That’s why Polaroid sun-glasses work – they block all the photons that are polarised the wrong way, so only let some light through.
Now, until something detects it, a photon isn’t in any particular polarisation – it’s in all of the possible polarisations at once. But once something has detected what kind of polarisation a photon is in, it’s always been that way – quantum causality works both ways in time. So you can set up an experiment that only detects photons of one polarisation, and that way you can send a message back to the past, to the photon emitter (light source) saying “Only send photons of this type”. If you do this the right way, you can send a photon back in time (but you can’t look at the photon that’s been sent back in time until it’s come back to the time you sent it from, or the experiment can’t work). That might sound mad, but it’s the way things are – accept it for now.
Now, by doing this, you can set up a kind of quantum ‘gun’ – set it up so that the photon going back in time tries to cancel out itself coming forward in time – all you do is put something in the middle that tries to change the polarisation of the backwards-in-time photon to the opposite of the forwards-in-time one. Changing polarisation is easy, and works about 96% of the time.
It never worked on the backwards-in-time photons.
This means that if you went back in time and tried to kill your grandfather, the gun really *would* misfire! Every time.
Now, assuming their experimental design wasn’t flawed and their maths works – and it looks OK to me, but I’m not a quantum physicist – then that means a lot of things:
Firstly, it means the universe is completely deterministic. There’s no such thing as chance.
Secondly, it’s strong evidence *against* the many-worlds hypothesis – the first such evidence I’ve ever heard of. It almost certainly means there’s a single universe.
Most interestingly, it means we can say goodbye to cause-and-effect. Effects can cause their own cause. For science-fiction fans, we’re living in the universe of Bill & Ted, the Doctor Who story Blink, and By His Bootstraps, (EDIT or of this rather nice short-short story by Simon Bucher-Jones) rather than Back To The Future or Pyramids Of Mars.
This of course means that access to a closed timelike curve (something that has never been observed in the real universe, but is theoretically possible), gives you essentially godlike powers. Got a closed timelike curve and want a million quid? Just put two pence in the bank and say “tomorrow, if my account has two milion pounds or less in it, I’ll take half of the money out and bring it back today and stick it in the account.” So if tomorrow you’ve still got 2p, you’d go back and put an extra penny in, which means that actually tomorrow you’ve got 3p in, which means… and the only stable way that can work out (other than you dying or something over the next day) is for the million pounds just to appear in your bank account.
Want to write a bestselling novel? Decide to print out five hundred pages just covered with the letter “A” and send it to a publisher. If they publish it and it becomes a bestseller, you send that back to yourself. If they don’t, you print out all the letter “A” apart from one “B” at the end and send that back to yourself to try that, and repeat – the only stable outcome is that you have a novel arrive that you never actually wrote but that will be an instant bestseller. And so on.
The possibility of time-travel in a *single, consistent universe* has never been one that’s really been taken seriously before, because it was just so absurd. I’m still 90% sure that there must be a mistake somewhere – the many-worlds hypothesis, as odd as it may sound, is far, FAR less ridiculous than this. But this is one of those things where either in a few months we’ll have a very quiet paper by Lloyd saying “Oops, I was totally wrong about everything because I forgot to carry the one” or in a hundred years’ time we’ll have a totally new understanding of physics based around this paper. I really can’t see a middle ground here…
Linkblogging for 12/10/09
Just a few quick links today:
An app for (ptui!) iPhone that splits the universe for you.
Terence Eden suggests we should mutualise the post office.
Rick Veitch draws Harvey Pekar as Darkseid.
Peter Watts wonders what the drug companies are going to do about the apparent increased effectiveness of placebos.
Pillock saw Yoko Ono in a Corolla.
And Marc looks at his favourite solo Lennon.
Baby Baby Baby You’re Out Of Time – Hyperpost 4
A revised and improved version of this essay is in my book Sci-Ence! Justice Leak! – hardback, paperback, PDF
One possible path of the positions of three particles, from Julian Barbour's The End Of Time
What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know. – Saint Augustine
This post comes with a health warning – I am talking here about quantum physics. There is nothing more likely to produce wrongheaded drivel than this, of the “did you hear, right, there’s this cat and it’s in a box, and if you look into the box you go into another universe?” variety. Even most professional quantum physicists, once they start talking about what the equations actually *mean*, tend to start saying things which every other physicist will find ridiculous and unscientific.
So with that in mind, please assume that everything I say here is wrong. What I’m going to talk about here isn’t the truth, but rather a set of ideas put forward by a group of physicists including David Deutsch, Max Tegmark and Julian Barbour, as I understand them based on their explanations. These physicists are all people who are respected in their fields, but who are definitely in the minority as far as their explanations of reality go, so I’m not talking here about what reality ‘really is’.
But I *do* think that not only are these ideas interesting in themselves, they’re also an influence on the comics of Grant Morrison, which I’ve been talking about and will be talking about in this series. I suspect the idea of Hypertime has its origins in these ideas, which are expressed most fully in Barbour’s book The End Of Time, and most clearly in Deutsch’s The Fabric Of Reality. I’m going to oversimplify hugely here, but I’ll give a bibliography at the end of books which only oversimplify quite a lot…
One of the basic problems in physics over the last century or so has been an experiment that anyone can do at home, at least in its basics. If you shine a point source of light through a double slit onto a screen, you see fringes of light and darkness – interference patterns. These patterns are characteristic of things that exist as waves, like sound, but we know from other experiments that light comes in particles, which we call photons.
Now, when a lot of light is being shone through the slits, the explanation seems simple enough – all the photons travelling through the slits are interfering with each other – bouncing off the photons coming through the other slit, if you like – which is why we get the pattern. But this pattern also happens if we send *one photon at a time* through the slits – it builds up into exactly the same pattern as when we send lots through at once.
So how can a photon interfere with itself (no sniggering at the back there)?
Well, we have an equation – the Schrodinger equation – which lets us predict very accurately (but statistically) how many photons will land where. It doesn’t tell us where any given photon will land, but it does say that given x number of photons travelling through the slits, so many will land here, and so many there. The problem is trying to explain what this equation *means*.
There are several different explanations of it, but the two most popular are the Copenhagen Interpretation and the Many-Worlds hypothesis. The Copenhagen interpretation essentially says that when you send a photon through a bit of card with two slits, it sort of ‘smears out’ in space and time, and is everywhere it could possibly be until we look at it. When we look at it, it decides to be in just one place, and it’s never been in any of the others – it’s retrospectively only taken one of the paths it smeared out across.
The many worlds interpretation, on the other hand, says that in fact there are loads of different photons – as many as there are different paths the photon could take – but that we can only see one, the others being in separate universes. But the photons still bounce off each other, causing the interference patterns.
Now, as far as the maths goes, these two give exactly the same results – at present we have no way at all of distinguishing between them, so choosing between them is mostly a matter of aesthetics – whether you think it’s neater to say “if we look at something, it’s magically in just one place and we don’t know why” or “there are a near-infinity of actually-existing universes out there, most of which only differ by things like the position of one electron in a star fifteen galaxies away”. Neither of these seem especially neat or preferable to me…
But some of the physicists who favour the idea of a multiverse go further. They point out that, looking at these equations, there’s nothing to differ the past and the future from other universes. What we see as moving forward through time could just as easily be explained as a line ‘drawn’ through ‘neighbouring’ universes – those which are almost identical, except for small movements which are in line with the laws of physics.
So instead of time passing in a single universe, our experience of time could equally be put down to a contour that can be drawn through a near-infinite number of points in a multi-dimensional configuration space. That line wouldn’t have to go in any particular direction, so long as it was a continuous line – the laws of physics are (with a couple of possibly-explicable exceptions) time-reversible anyway.
So why do we have a sense of time going in one direction? Well, there are more ways of arranging things in a disordered manner than in an ordered manner, which means that there are more disordered universes than there are ordered ones. So if you draw a line from one universe (with enough order in it to have human beings who can think and write blog posts and so on) to another one very close to it (and therefore very similar), the chances are that the one next to it will be slightly less ordered. And the next one in the line will be less ordered again.
From this, then, we get a sense of direction – at any point, things are going to act in ways consistent with the laws of physics (because the universes next to us are those where particles have moved in ways it is possible for them to move), but overall disorder – entropy – is going to increase. So if we hit a cup with a hammer, we see it smash, but if we hit smashed crockery with a hammer, it doesn’t turn into a cup – because there are lots of ways to arrange those molecules into smashed crockery, but only one to arrange it into a cup.
But just because we’re experiencing one line, that doesn’t make it the ‘true’ line. There are a near-infinite number of ways to get to any universe, and a near-infinite number of directions it can go. That means there are a practically infinite number of those lines, all crossing each other. Every line that’s consistent with the laws of physics is a ‘universe’ just as real as our own – there is one ‘universe’ where every instant in its history up until the point at which I hit the next comma in this sentence is different from the instants in this universe, and where every instant going forward is different, but which overlapped with this universe at precisely that point and only that point. In fact (assuming this interpretation is true) there are an infinite number of such universes.
Now, doesn’t that sound to you like
Take a glass sphere studded all over with holes, and then drive a long stick right through the middle of it, passing exactly through the center of the volume. That’s the base DC timeline. Jab another stick through right next to it, but at a different angle, so that they’re touching at one point. That’s an Elseworlds story. Another stick, this one rippled, placed close in so that it touches the first stick at two or three points. That’s the base Marvel timeline. Perhaps others follow the line of the DC stick for a while before diverging, a slow diagonal collision along it before peeling off. This sphere contains the timeline of all comic-book realities, and they theoretically all have access to each other.
?
So for ‘comic-book science’, Hypertime is, if not actually true (remember, I’ve been throwing around metaphors, generalisations, and general fudging left, right and centre here), at least far less ridiculous than it sounds.
But there are some people out there who say that doesn’t actually go far enough – that it’s too conservative a picture of reality. Max Tegmark is one of them.
Tegmark wonders why the set of universes seems to be limited to those that are physically possible – those where the particles are in an arrangement that’s consistent with the laws of physics. He also wonders why it appears possible to describe the laws of physics mathematically, and he’s come to a conclusion that is unprovable – possibly even in theory – but is at the very least interesting.
Tegmark points out that if we can reduce the laws of physics to one equation (as some physicists hope) or a set of equations, then the multiverse described above is the set of all possible solutions to that equation. The multiverse is acting like what in mathematics is called a ‘formal system’ – in fact it *is* a formal system, from the point of view of mathematics (mathematically, if two things behave exactly the same way, they are the same thing) – it’s a set of rules, plus a starting point.
Tegmark wondered why that particular formal system would be the one that would be ‘real’, and he’s been unable to come up with any reason why our one would be ‘real’ but the others wouldn’t. Absent other explanation, he’s decided that our multiverse *isn’t* any more real than the others – that there are as many multiverses out there as there are consistent formal systems. So there’s a multiverse where the laws of physics are the same as our laws of arithmetic, and another one where the laws of physics are the rules of 2D Euclidian geometry. In Tegmark’s neo-Platonic (though he hates the term) view, numbers and triangles aren’t just abstract ideas – they’re things that physically exist, and are precisely as real as you or I.
And so if Tegmark is right, somewhere out there A. Square’s great-great-grandson is busily writing on his blog about these strange, bizarre ideas of Hyperspace that some geometers have been coming up with, where there’s a third spatial dimension…
A brief pop-science bibliography
Here’s a list of books on these subjects that should be comprehensible to people who don’t like looking at equations full of Greek letters. You can’t really grasp this stuff without serious study (and not even then, quite possibly – I’ve read original works by Dirac, Bell, Wheeler, Feynman and so on and still don’t have anything like a proper understanding) but these are all reasonable reads:
The End Of Time by Julian Barbour – a dense read, aimed equally at physicists and a lay audience.
The Fabric Of Reality by David Deutsch – gets far too speculative for my tastes, but a stimlating read.
The Universe Next Door by Marcus Chown – a good summary of the more extravagant ideas at the frontiers of research.
Quantum Reality by Nick Herbert – a very straightforward account of quantum physics.
New Theories Of Everything by John Barrow – a very dense read, on branes, M-Theory and all that stuff.
Programming The Universe by Seth Lloyd – a brief introduction to the field of quantum computing.
Timewarps by John Gribbin – a very 70s book (Gribbin, usually fairly hard-headed, talks here about stuff like past-life regression as a serious possibility) but my first exposure to these ideas. Gribbin’s later In Search Of Schrodinger’s Cat is the ‘canonical’ pop-science book on quantum strangeness.
Review : David Deutsch – The Fabric Of Reality
This is a science post…
I was going to write another post about Final Crisis, but then I realised that I would have to explain a lot of what I was talking about, so this is a “I’m saying this so I can say this” post. It’s a bit of a tangent really, but I hope that you’ll be able to see the connections to some of the Final Crisis posts. Tomorrow I’ll write more about FC, and then I’m going to leave the subject of comics for a bit to do some politics, Doctor Who and music posts…
The Fabric Of Reality is an attempt by Deutsch, a physicist who specialises in quantum cosmology and quantum computing, to explain for the layman the worldview he has come up with, sort of a unified theory of reality (not to be confused with the unified field theory which physicists have been searching for for decades). This worldview is based on four strands:
The multiversal interpretation of quantum theory
This view states that every time anything could happen, it does – there are a near-infinite number of universes which differ by the smallest possible measurable amount. In Deutsch’s formulation of the multiversal interpretation, these universes aren’t ‘created’ by the ‘choices’ at the quantum level, rather every instant of time is in effect one point in a giant multi-dimensional array, and what we perceive as time passing is merely one path through this array.
Popperian epistemology
The philosopher Karl Popper stated that scientific knowledge grows by a process in which hypotheses are created and tested to destruction, with the hypotheses either being disproved or surviving, in a clear parallel to Darwinian natural selection. This can be contrasted with Kuhn’s ideas of ‘paradigm shift’. (And see this, which Holly serendipitously sent me while I was writing this…)
Dawkins’ modifications of evolutionary theory
Richard Dawkins, in his bestseller The Selfish Gene, posited that evolution acts, not at the level of the organism or species, but rather at the level of the individual gene.
and the Church/Turing hypothesis
This states in effect that any operation that can be performed by any computer can be performed by any other computer, given enough time and storage capacity.
Deutsch states that all these are the ‘current best thinking’ in their relative domains. Here he is quite probably wrong. The many-worlds interpretation is a minority view among quantum physicists , although its predictive power is the same as any other interpretation and Deutsch makes a good case that it is the clearest explanation. Popper’s epistemology, while I think he’s right, is nowhere near as popular as Kuhn’s. Dawkins’ view, while popular with many biologists, is regarded with suspicion by others (see Jack Cohen’s writing for example, as well as obviously Stephen Jay Gould) though if one were to reword his ideas taking gene to mean ‘all means of transmissible information storage within the organism’ then it would work better. And the Church/Turing hypothesis has never been proven (it’s a mathematical statement so concepts of proof apply in a way they don’t for science) though it’s strong enough to be the basis of pretty much everything we do in computing today.
However, one *can* say that none of the explicit bases for Deutsch’s argument are provably wrong, and from them he builds a consistent view of reality. This view requires a lot of implicit extra assumptions, though, including that the universe is fundamentally understandable, that consciousness is a purely physical process, that the human brain is a computer of sorts, and so on. Most of these are justifiable using Occam’s razor (which Deutsch uses a *lot* and which I must post about soon – I was having an argument with Mat and Jennie about this the other day and they quite rightly said that William of Ockham used the original formulation to essentially say that God explains everything. However, it can be shown that a reformulation of Occam’s razor is necessary and sufficient as a basis for the scientific method when combined with some mathematical proofs…) but with each of them the probability of his worldview being the correct one becomes less – if any one of these is wrong, his whole argument falls down.
It’s also interesting which strands of scientific theory he’s chosen as ‘fundamental’ (in Deutsch’s view, which I think is correct, ‘fundamental’ should mean ‘has the most explanatory power’. All else being equal the best story wins. This will be important when I get back to comics eventually…). Were I to attempt something similar to Deutsch’s book (and I’ve been tempted to – only my lack of formal qualification has stopped me, for which the world should probably be eternally grateful) I would have chosen, say, quantum theory (without any particular interpretation being put on it), the second law of thermodynamics, Ashby’s Law of Requisite Variety (Gavin R, if you’ve never read Ashby, you should – he’s at least as important as Shannon) and Bayesian statistics. Oddly, I would have come up with a formulation that is not that dissimilar from what Deutsch comes up with…
Deutsch’s book is by turns fascinating and infuriating – he shares a lot of qualities with his Oxford colleagues Dawkins and Roger Penrose (with whom he fundamentally disagrees, but in an admiring way), making me at several points want to throw the book across the room screaming “You stupid, STUPID man!” (especially in the last chapter – I want a moratorium on anyone talking about ‘the singularity’ unless and until it actually happens, please) but occasionally coming up with something that makes me sit up and say “That’s actually very interesting…” (something Dawkins has never achieved). I also found his introduction (about the childhood horror at not knowing *everything*) very easy to relate to.
But his main insight is simply this – Information can, in this worldview, be described as “That which remains constant more often than not between universes”. I’ll explain why this is tomorrow, before talking about DC Comics and Grant Morrison some more…
Linkblogging for 06/02/09
Sorry for the temporary hiatus in Final Crisis Week yesterday – I discovered that the local IMAX was showing a double bill of both Batman films for nine quid, and so that was five hours of the day gone… I was going to make up for it this morning, but then realised I can’t write in the mornings.
(BTW, I’m building to something with those posts – the fact that the last couple have been sidetracks, as will the next one, shouldn’t let you think I don’t have a point…)
Anyway, linkage:
The Mindless Ones continue their group look at Final Crisis 7. Doctor K also has some thoughts on this.
(Does anyone else think that it’d be a really fun, if totally impractical, idea to do a ‘The Internet On Final Crisis’ (or even On Morrison) book collecting these things? There *must* be several books worth of stuff scattered over a dozen blogs, and some of it’s mind-blowingly good…)
Holly talks about her favourite interpretation of quantum physics.
Laurie Penny has declared the next ten days to be National Take A Photo Of A Policeman Day, which I would be joining in with if I wasn’t the only person I know to own *no* image recording devices at all…
Brian Hibbs has some stuff on Diamond’s recent decision not to stock comics below a fairly high level of expected sales (note for non-comics people, Diamond is the distributor that has an effective total monopoly on comics as individual issues, and a huge chunk of the collected edition market).
And from The Daily Mash – “CUTS in school music budgets could lead to a cataclysmic surge in Coldplay, Ofsted has warned.”
Linkblogging for 17/01/09
I’m still far busier than I expected this week, so I’m still behind on my email correspondence – apologies to those who’ve emailed me recently.
Anyway, in lieu of a longer post, here’s some links:
Debi writes about Thomas Hariot – the most pioneering scientist you’ve never heard of.
Bobsy shows us his pants.
Over on Lib Dem Voice they’re talking about what the ‘liberal attitude to immigration’ should be. Some of the comments there make sense, but some are horribly, nastily racist. Let them know what you think…
People buying tube tickets will soon be automatically giving their consent to be searched by transport police. Well, that’s one more reason for me to avoid That London…
An interesting post about the Einstein/Bohr dialogue about quantum physics.
Cerebus: A Diablog continue their reading of the greatest comic series in history.
Andy Partridge discussing how Jack Kirby influenced one of his songs. (Surprising, because Partridge has always struck me as more of a DC person, and here he’s talking about Ant-Man. Still, it’s another example of XTC and comics, two of my favourite things, overlapping).
Free comic stories by Rick Veitch and Mark Evanier and Tom Yeates and some others.
And pillock has an excellent post on From Hell.
Books You Should Read : Anathem
One of the better Xmas presents I got this year was Neal Stephenson’s latest novel, Anathem. I’m only around 500 pages into it (it’s 900 pages + long) but I can already enthusiastically recommend it as the best new book I’ve read all year.
Stephenson is someone whose work I admire intensely (although I’m ashamed to say I’ve still not finished his huge, 3000 page Baroque Cycle trilogy – it’s so dense that without reading it uninterrupted I can’t keep track of the many threads, and lose the plot somewhere around the 1800-page mark and have to go back to the beginning. I plan to take a week off next year and spend it just reading those books).
After the technothriller-of-sorts Cryptonomicon and the historical novel that is the Baroque Trilogy, Anathem sees Stephenson’s return to science fiction, the genre in which he made his early impact. But rather than the cyberpunk of The Diamond Age or Snow Crash, this is hard Campbellian SF with some slight fantasy-esque worldbuilding – it reminds me more than anything of Arthur C Clarke’s work, but with a much better prose style and more ideas.
Science fiction fans often defend SF as ‘the real literature of ideas’, and to an extent that’s true. Good science fiction relies more than any other genre on new ideas. Unfortunately, the ideas themselves are often relatively trivial ones – often solutions to hypothetical engineering problems. One could come up with a pretty good traditional SF plot by, for example, constructing a race that evolved on the outside of a Dyson sphere by feeding off the black body radiation it emits, working out their biology and society, then having them discover that their world has an inside.
Something like this happens in Stephenson’s novel – he has a meticulously worked out pseudo-monastical order of mathematicians (which reminded me of Logopolis, especially in their rejection of computers, but is far more well-conceived than the Doctor Who story) on a fairly detailed world coming into contact with aliens who (at the point I’ve reached) are unknowable in almost every way. So far, so ordinary.
But Stephenson is one of the few novelists I know of who is *really interested* in ideas of all sorts – cultural, political, economic, scientific and so on. Cryptonomicon and the Baroque Trilogy were linked not only by one recurring supporting character, but by the ideas Stephenson was working out (about information flow being the same as flow of value, about to what extent it is possible to represent the world symbolically, about truth and deception, about the creation of modern capitalism, and about looking at history not as a struggle between ‘great men’ but between great ideas). His other novels were similarly based around Big Ideas – and not just one per novel, but several interacting.
In this regard Stephenson reminds me of Grant Morrison, but Stephenson is the better prose stylist and has the space to work the ideas out more thoroughly (Stephenson also appears to be far more instinctually conservative than Morrison – while Morrison’s rebellion against Baby Boomer generation immediately before him tends to be in the form of fetishising youth and youth culture, Stephenson seems to wish the old hippies would just grow up and get over themselves). While Anathem presents itself as a science fiction story, the plot is merely a convenient hook on which to hang a complex net of ideas.
In this case, these start with a fairly simple neo-Platonist world view (that mathematical concepts have an existence separate from human perception, in some other level of existence), which Stephenson links with the many-worlds hypothesis in quantum physics, and with Penrose’s idea that the brain must work on a quantum level, and with mathematical concepts of phase space, to postulate a multiverse with information flow from ‘lower’ to ‘higher’ levels, and with brains acting as quantum computers. In this model, our understanding of what is within the range of the possible – our mapping of the phase space – (for example the way we ‘intuitively’ know that a lead weight is more likely to fall to the floor than float in the air) comes from interference with the copies of our brains in close parallel universes.
Now, I happen to think this world view is almost certainly wrong (Platonism makes little sense to me, and Penrose strikes me as the same kind of half-bright person as Dawkins, his argument being little more than “I don’t understand thought, and I don’t understand quantum physics, so they must be the same thing”), but the way Stephenson jams the ideas together – and the many, many other ideas he throws out – is beautiful. During the action sequences I keep finding myself thinking “Oh,enough with the being rescued from a lynch mob by shaolin monks – get back to the discussion of the objective reality of Plato’s forms!”
One common criticism of this book has been the large number of words Stephenson has made up, but this is completely invalid. In a world with no Socrates or William of Ockham or Pythagoras, you can hardly have characters talking about Socratic dialogue or Occam’s razor or Pythagoras’ theorem. Many of his new coinages are very, very witty, and there’s the additional fun of dictionary entries studded throughout the text (the entry for ‘bulshytt’ is particularly worth reading).
Not that the book is perfect – the sequences where the plot is advanced through action don’t work nearly as well as those where the plot is advanced through dialogue, and Stephenson also chooses to depart from his normal method of having several viewpoint characters in interweaving plot threads, instead giving us a single first-person narrator throughout the story. While the reasons for this make a lot of sense (the readers only get hints of the big picture in tiny drips, and this is accentuated by the fact that the main character is, while hugely intelligent, a 19 year-old who’s spent almost all his life in a monastery), one of Stephenson’s biggest strengths is his ability with character. He’s particularly good at writing about a few different masculine types of personality (very non-verbal military men and introverted, logical, mathematician types) and showing the commonalities in their perceptions of the world. By showing everyone through the lens of one character’s perception, he has removed this particular string from his bow, so there are (at least in the first half) no scenes like Randy’s Cap’n Crunch-eating techniques or Laurence’s ‘fucking Mary’ plan from Cryptonomicon – where in his earlier books one comes away thinking about the ideas and about individual character moments, here what sticks in the mind isn’t so much the characters as the world – I have only a dim idea of the characters of any of the individuals in the story, but a very clear mental picture of the great Clocks, and how the doors open for Apert, and of the spaceship with its geometrical proof.
If you’re at all interested in the nature of consciousness, the nature of reality, mathematics, the possibility of contact with alien life, the possibility of parallel universes or just a good story, Anathem will set your mind ablaze in a way very few novels will.
Linkblogging For 25/11/08
Just a few quick links today. Please note there will be no linkblogging tomorrow. The last issue of Batman RIP is out tomorrow in the US, but not til Thursday in the UK. While I don’t normally avoid spoilers – if something can be spoiled by knowing the ending, it’s usually not worth it – this is a bit different, as it’s a story that’s kept me on the edge of my seat for more than two years now, and I want to see how Morrison ties it up without hearing the ending somewhere else first. So I shall be avoiding most of my usual net haunts tomorrow, and unable to find anything to link to, until I can get my copy.
Anyway…
Gavin Burrows, who you may recognise from his comments here, has a good post up on Dylan’s John Wesley Harding.
Alex Wilcock has a post up about Labour’s disgraceful, criminal treatment of mental health services, as well as their attitude toward the poor. Wilcock doesn’t really go far enough – anyone who thinks that Labour have any concern at all for the disadvantaged, remember that Labour have cut, on average, two mental health beds per day since they came into power. I could rant for hours – days – about the disgraceful state of the mental health system in this country, about how it demoralises staff until they quit like I did, or until they become ill themselves, about how it fails patients, who get kicked out as soon as they’re semi-coherent in order to free up the bed, only to return a few weeks later, and about how it puts patients, staff (such as my wife) and the general public in danger to save a few pennies… Wilcock’s points about the current benefits system are entirely correct too…
An interesting thing at Scientific American about the converse of quantum tunneling…
And Tim O’Neill at the Hurting is doing a great series of posts on comics culture in the early 90s and the Death Of Superman storyline. I only have a URL for one of them in my buffer, but you should be able to get to the rest from there.
Quantum Physics and the DCU
A revised and improved version of this essay is in my book Sci-Ence! Justice Leak! – hardback, paperback, PDF
Sorry there’ve not been many comics-related posts recently, but with the exception of the last issue of Batman, which I’m waiting to review until the end of the RIP storyline, there’s not actually been a comic worth writing about since All-Star Superman ended. There’ve been plenty of decent comics, in a sort of “this is quite fun, I suppose” way, but nothing that I’ve had anything to say about. I miss 52 and Seven Soldiers…
Of course if/when the Final Crisis related things get back on schedule, I’ll have a lot to say…
So I thought I’d talk about the different interpretations of quantum physics, the extent to which each of them appears to apply in the DCU, and why that leaves Hypertime as the only *actually consistent* interpretation of DCU physics.
Incidentally, when I talk about the DCU here and in other posts, I’m not talking about what’s officially ‘canonical’ as much as I’m talking about what comics I personally bother remembering. In ‘my’ DCU, no Batman story told between Alan Grant leaving and Grant Morrison coming on happened, 52 happened but Infinite Crisis didn’t, Morrison’s Doom Patrol happened but Byrne’s didn’t, and so on…
There are three major interpretations of quantum physics, which I shall now grotesquely oversimplify. All these interpretations come from a single fact, which is that the results of some experiments change depending on the results people look for. Richard Feynman once said that all quantum physics can essentially be explained by saying “Remember the double-slit experiment? It’s like that”, so I’ll talk in terms of that experiment (or, more precisely, a variant called the quantum eraser experiment ).
To oversimplify this a lot (the details are all wrong but the ideas are right – look it up if you want precision) – if you shine a light through a piece of card with two very thin slits in it, onto a screen, you get an interference pattern which can only be caused by light acting like a wave. However, if you put equipment in the slits to detect individual particles, then you get a *different pattern* which can only be explained if light is made up of particles, not waves. If you leave the equipment there, but turned off, it acts like waves again. Weirdest of all, though, if you turn the equipment on, *but don’t record the results*, or delete the results before you can look at them, it still acts like waves. In other words, behaviour of the light *in the past* is dependent on the information you know *now*.
This has been interpreted in a number of ways, but there are three interpretations that have received most publicity . The ‘orthodox’ interpretation is called the Copenhagen interpretation, and essentially says that everything exists in a fuzzy state until something observes it, which makes the universe ‘choose’ what has happened. The reason that, say, the Moon is there, according to this interpretation, is because people keep looking at it (or looking at effects it causes, like the tides). If everyone ignored the moon long enough, by this interpretation, it would go away.
More accurately, it says it makes no sense to talk about anything unless we can actually measure it. The advantages of this interpretation are that it’s parsimonious – it doesn’t require any new entities being created – and that it just takes the equations and experimental results absolutely literally. The disadvantages are that it means we can never talk about an objectively existing universe – that it denies even the existence of such a thing – and some argue that it gives an undeserved primacy to consciousness, making the universe depend on the existence of minds (though some, such as Heisenberg, would argue with this). Its detractors have characterised it as nothing more than solipsism, and it is most popular among those who think of themselves as pragmatists, who care more about the results than about what the results mean.
The best-known interpretation among the general public is the many-worlds interpretation of Everett, Wheeler and Graham, which posits that any time anything could happen in two different ways, the universe itself splits into two, with each universe being identical except for the position of one photon (or whatever). The advantages of this interpretation are that it fits all the known facts, that it does not get rid of an objectively-existing universe, that it’s easily comprehensible, and that it doesn’t make the fact of observation especially important. The disadvantage – and it is a substantial disadvantage – is that it means that in the time it took me to write this sentence, a trillion to the power of a trillion new universes were created, all absolutely indistinguishable from each other except that somewhere three galaxies away a photon hit a helium nucleus which in this universe it missed. To say the least, this seems to go against Occam’s razor. This interpretation is most popular among science-fiction fans and those who want the universe to be a more exciting and interesting place.
The third main interpretation is the hidden variable hypothesis, specifically the version advanced by David Bohm. This states that all the quantum results that look like they’re probabilistic are in fact deterministic, but controlled by some factor we don’t yet know. For various reasons that factor would have to be something ‘nonlocal’, which means in effect it would be outside of normal space-time, and it would quite possibly be impossible to measure. The advantage of this hypothesis is that it preserves a single, objectively-existing universe which isn’t dependent on our measurement, and that it suggests there’s an underlying order to the universe (the implicit assumption of most people). The main disadvantage is that it involves invoking something outside the normal universe which we can’t measure yet. It also has the disadvantage, as I’ve linked to a couple of times recently, that John Conway and another mathematician whose name I can’t remember have recently proved that the only way this can be true is if we give up the concept of free will altogether.
This interpretation is most favoured by both ultra-fundamentalist materialists who are very convinced that a totally deterministic, objectively existing measurable universe must exist, and by religious/mystical people who see the implicit order or hidden variable as being a manifestation of the will of God (although the God being talked about is not usually the god of the Abrahamic religions but some more Eastern concept like the Tao, or the Deist Nature’s God). In fact this description is rather like the description in C.S. Lewis’ The Screwtape Letters of the universe as seen by God.
All of these interpretations (plus others such as the transactional and relational interpretations, which are very close to one or more of the above) seem equally valid in our world (I just typoed that as equally valis…) and make the same predictions for every experiment we’ve thought of. So which of these hypotheses appears to be correct within the DCU?
Firstly, we appear to be able to dismiss the Copenhagen interpretation out of hand – there’s never been any mention of it in any DCU story I’ve read. However, there is an ‘out of sight, out of mind’ thing going on in the DCU, where if a character stops appearing in comics, after a while they just stop existing (like all the recent Supergirls). But that’s stretching a metaphor. We’ve never seen any evidence of the DCU behaving in a Copenhagenist manner.
[EDIT - RAB in the comments (and read the comment in question, it's a good'un) has pointed out that Limbo from Animal Man could be interpreted in a Copenhagenist way. He’s also linked to this post, which is a rather good reaction to the reintroduction of the multiverse in 52 and ties in with a lot of this stuff).
So we now turn to the many-worlds interpretation. This *has* been brought up before, in things like Peter Milligan’s rather wonderful ‘Schrodinger’s Pizza’ storyline in Animal Man (which really needs reprinting at some point). But while the DCU does currently have multiple universes, these seem to be strictly limited, and the differences between them are macroscopic rather than microscopic in nature. And also, apart from the Hypertime stories (which I’m removing from consideration here because that would be to presuppose the conclusion) most stories involving alternate realities, such as the recent Booster Gold stories or Rock Of Ages have involved an ‘incorrect’ timeline being created which is then fixed. So there is more evidence of this than there is of the Copenhagen interpretation, but it still seems fundamentally wrong in the DCU, where timelines can be altered.
Finally, there’s the Hidden Variable hypothesis. This is the one used by Grant Morrison in Animal Man, and Matt Sturges has recently used it (very much in passing) in Blue Beetle. It also fits the facts in that there *is* something outside the DC Universe affecting it – namely the various writers, artists and editors who work on the stories (unless you consider the infant universe of Qwewq to be part of the DCU of course). It seems the best-fitting of the various interpretations in many ways, and is also the one (of those three) that would allow the intelligent universe that Grant Morrison seems to be pushing for (with the hidden variable here being the DCU’s own sentience). However, as I’ve explained before, in the context of the DCU this would ultimately mean that Darkseid wins, and we all know that Darkseid doesn’t win.
So that leaves a combination of elements from the different interpretations – especially the last two – as the only way forward. It is my contention that Hypertime fits the bill, and is thus the only way to actually make sense of the various different, conflicting stories that have taken place in the DCU. More of this later, including how this ties into information theory…
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