26 ms·

Reality doesn’t exist until it is measured, quantum experiment finds

• dang 11y ago
  This experiment has been posted to HN a few times in recent weeks, but I'm not sure it's had a real discussion yet. The paper is at http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys3343.html http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys.... We changed the URL of this submission from http://www.independent.co.uk/life-style/gadgets-and-tech/news/reality-doesnt-exist-until-you-look-at-it-pioneering-quantum-physics-experiment-finds-10305047.html http://www.independent.co.uk/life-style/gadgets-and-tech/new....
• z5h 11y ago
  What does it mean to exist? A thing exists specifically when it affects something else. What is measurement? It's a reciprocal affecting. So does a thing which is not affecting anything else and not being measured exist? No! QED
  • anti-shill 11y ago
    depends on what the meaning of "is" is....
    • hellbanner 11y ago
      E Prime is English without the definition of the word is, precisely for the sake of exploring language.. see also: https://en.wikipedia.org/wiki/Quantum_Psychology https://en.wikipedia.org/wiki/Quantum_Psychology
  • themgt 11y ago
    Right. This way of describing it is much closer to "zero-worlds" or relational quantum mechanics, and to my mind is a far simpler, deeper way of understanding what's really going on - reality is simply all entanglement. What really still gets me is the way it's not simply that the atom wasn't interacted with, but that if the information about the interaction never leaks to the outside world - if it's "erased" after the interaction takes place - then the system still behaves as if the interaction never took place. It undermines not just the concept that matter really exists, but time as well.
    • dmvaldman 11y ago
      Do you have a source for this "information leaking" concept. I remember hearing about an experiment confirming such an idea, but I can't recall what it was.
      • themgt 11y ago
        I'm not sure the exact experiment performed in the article (which sounded similar), but I've always thought the delayed choice quantum eraser was about the best example of this, once you spend some time understanding the experiment and results: https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser https://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser
  • wtbob 11y ago
    > What does it mean to exist? A thing exists specifically when it affects something else. What is measurement? It's a reciprocal affecting. All that's starting to sound an awful lot like Orthodox Christian theology about the essence of God…
    • chadzawistowski 11y ago
      Can you elaborate on the similarities? I took a course on medieval philosophy and theology (Anselm, Aquinas, Avicenna, and so on) so I am earnestly interested, but the connection isn't jumping out at me.
      • superpatosainz 11y ago
        I think he means Aquinas' Quinque Viae
        • chadzawistowski 11y ago
          Hmm, it does bear resemblance to the argument from contingency, thanks!
• graycat 11y ago
  We know that light bends near a gravitational field with a big gradient before it is "measured". Sounds like that light existed and generated and responded to a gravitational field after it was emitted and before it was detected or measured.
  • tiatia 11y ago
    The light may be in a state of being bended and being not bended until you observe it...
    • graycat 11y ago
      I doubt it: What is bent is the wave function. There's no ambiguity there.
      • tiatia 11y ago
        It addresses the inability of the classical concepts "particle" or "wave" to fully describe the behavior of quantum-scale objects. As Einstein wrote: "It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do"
• westoncb 11y ago
  This is of course extremely interesting and probably important for understanding our universe—but how is it helping anyone to say something like, "...with scientists performing a famous experiment and proving that reality does not exist until it is measured." The statement is like a distraction at a magic show, drawing the reader to the glittery 'reality' and 'exist,' which are totally undefined so the reader's imagination can rove without limit. Maybe this is really just a fundamental challenge to our assumptions about motion of particles or information transfer in the universe. Isn't that interesting enough without these vague, human aggrandizing assertions about creating reality?
  • deleted 11y ago
    [deleted]
  • epitomix 11y ago
    "Maybe this is really just a fundamental challenge to our assumptions about motion of particles or information transfer in the universe." Check out this TED talk on just that subject. http://www.ted.com/talks/donald_hoffman_do_we_see_reality_as_it_is http://www.ted.com/talks/donald_hoffman_do_we_see_reality_as... Here's the punch line, space, time and matter are components of a user interface produced through evolution. We don't take the desktop and icons of our computer UI literally and we shouldn't take our evolved UI literally either.
    • westoncb 11y ago
      Cool. I'll check it out!
    • paxcoder 11y ago
      Fun to think about, but his argument is a non sequitur.
      • epitomix 11y ago
        Maybe, but my wording is not his argument. Here is a blog version of the same idea. https://edge.org/response-detail/25450 https://edge.org/response-detail/25450
• nosuchthing 11y ago
  Observation does not exist until observed, experiment finds.
  • nosuchthing 11y ago
    Reality is that which, when you stop measuring it, doesn’t cease to exist.
  • NeutronBoy 11y ago
    If a tree falls in the woods...
    • tarpherder 11y ago
      .. and nobody hears it, then is there even ground for it to fall onto?
      • iagooar 11y ago
        And is the tree really there?
• andyl 11y ago
  Lazy instantiation.
  • kiernan 11y ago
    realization
  • has2k1 11y ago
    Just like python generators.
    • andyl 11y ago
      reality must be dynamically typed.
      • lucozade 11y ago
        Could just be an ADT. photon :: (Wave | Particle)
  • sosuke 11y ago
    You made me remember a comment I made some months ago about the speed of light being a performance optimization on a post asking if reality was a computer simulation. https://news.ycombinator.com/item?id=8638150 https://news.ycombinator.com/item?id=8638150 Lazy loading makes perfect sense to me!
  • Strilanc 11y ago
    A lazily computed simulation would lazily compute entities not seeing the laziness. Laziness should have no measurable effect within the simulation, unlike quantum mechanics. As an analogy, consider Hashlife [1]. It works very differently than your typical game of life implementation... but it still agrees on all the intermediate states! The board won't behave normally for most implementations, but end up in states spelling out "we know we're being cached hierarchically!" when you simulate with hashlife. 1: https://en.wikipedia.org/wiki/Hashlife https://en.wikipedia.org/wiki/Hashlife
• hellbanner 11y ago
  How can you measure what doesn't exist?
  • photonic29 11y ago
    You can make an observation of a system whose state is undetermined. By interrogating the system for its state, a state becomes determined. Suppose, for example, that you have a flipped coin and sent it rotating in space, never hitting the floor. Is it heads or is it tails? Until it is looked at, the question doesn't really make sense. And for this case, we'll define "looking at it" to mean sticking out your hand and catching it. There is a probability that it's landed heads up in your hand, and a complimentary probability that it's landed tails up. Once it's in your hand though, you can confidently say which state it's in. Now, you could definitely take issue with this example, because you could argue that the rotation of the coin is well described, so with initial conditions, you can predict its position at any given moment. But imagine a microscopic quantum system, and, for the sake of this simple explanation, believe that its "rotating through the air" state really does not have any precise heads or tails definition. Until something gets in the way of that system, creating an interaction that exchanges information about its observable state, it's not meaningful to say that it's in one of the observable states at all. A superpositition of states, as such, is essentially the representation of a state in terms of a basis set of observables. In the case of the coin, heads and tails are the two observable states, they are orthogonal, and they fully represent the state space of the coin. You could flip the coin, and put its state vector into the form of sqrt(2)/2 * Heads + sqrt(2)/2 * Tails. This state isn't observable, but it can be described in terms of observable components, where the coefficients represent the probabilities that a given observable state will be measured upon observation.
    • pdonis 11y ago
      > You can make an observation of a system whose state is undetermined. By interrogating the system for its state, a state becomes determined. For QM, this is not correct, although it's a common misstatement. The correct statement is this: you can make an observation of a system which is not in an eigenstate of the measurement operator you are using. After the measurement, the system is now in an eigenstate of the measurement operator--i.e., the act of measurement changes the state. Note that this is only true on a collapse interpretation, like Copenhagen. On a no-collapse interpretation, like MWI, the "observation" is just an interaction that entangles the state of the measuring device with the state of the system being measured--it's all just unitary evolution. > You could flip the coin, and put its state vector into the form of sqrt(2)/2 Heads + sqrt(2)/2 * Tails. This state isn't observable* Yes, it is; but it isn't observable by a simple method like looking to see if the coin is heads or tails. But according to QM, every state is an eigenstate of some operator, so there will be some observation that will distinguish sqrt(2)/2 * Heads + sqrt(2)/2 * Tails from the state that is exactly orthogonal to it, which is sqrt(2)/2 * Heads - sqrt(2)/2 * Tails.
• bcheung 11y ago
  So that's why kids cover their eyes when they want to hide.
  • hypertexthero 11y ago
    Or put on completely opaque sunglasses.
  • EarthLaunch 11y ago
    HN doesn't appreciate when you concretize their epistemology.
    • DanWaterworth 11y ago
      HN doesn't appreciate when you use words they don't recognise. It makes them feel stupid and that is a Bad Thing™.
• davidrusu 11y ago
  Clever optimization by our simulators, Big up
  • marwatk 11y ago
    I've always wanted to read (or write?) a book about us determining we are in a simulation, but we find subtle flaws like this we're able to exploit in weird ways. Kind of like breaking out of a VM through register flaws or something. Anyone know of a story along those lines?
    • gall 11y ago
      Check out Greg Egan's Permutation City in which sort of the opposite happens.
      • nitrogen 11y ago
        I'm reading that book right now, and so far it's good. One can also read: Anathem, Snow Crash, http://qntm.org/ra http://qntm.org/ra, or (extremely NSFW) The Metamorphosis of Prime Intellect. All of them explore the nature of reality and consciousness in some way. To the parent commenter, please write your story. The world always needs good fiction.
        • mhink 11y ago
          The Metamorphosis of Prime Intellect is one of my favorite sci-fi novellas. But yes, extremely unsuitable for anyone with a weak stomach.
        • kale 11y ago
          Yahtzee (of Zero Punctuation) wrote a novel that used simulation as a plot device. It's called "Mogworld". I thought it was well done.
      • sdenton4 11y ago
        I just finished reading Permutation City a couple weeks ago. Good fun. The core conflict is between two different approaches to modeling, via mimicry of existing systems versus really interesting cellular automata. The automata version doesn't need to 'cheat' in the same way, and is thus a bit harder to find the edges of... (Hopefully that doesn't count as spoilers.)
• Moshe_Silnorin 11y ago
  Or, maybe, Everett was right.
  • deciplex 11y ago
    Most physicists or, depending on who you talk to, nearly half of physicists, would appear to agree with you. I'm convinced that the Copenhagen interpretation remains popular because by making observation itself an integral part of the theory, you allow us to postulate that there is something special about human brains. But 'mysterious observation' is the luminiferous aether of quantum mechanics. photonic29: I would like to continue our discussion, but HN has some kind of stupid rule where I can't make more than five posts within a (I think?) 12 hour period. I don't know if this is a general rule that applies to everyone, or simply one of the innumerable passive-aggressive account handicaps our gracious mods will afflict us with if we catch them on a bad day. At any rate, I can't post anymore for now, so our discussion about MWI and Copenhagen interpretation can't happen. Sorry.
    • photonic29 11y ago
      Is that really the case though? An observation collapses a wave function. The Copenhagen interpretation suggests that the collapsed state arises from a probability distribution, but it does not address the "fundamental" origin of that distribution. MW attempts to address it by suggesting that the rest of the reality just went elsewhere, rather than disappearing or never having existed at all, but it still does not explain why "we" get "this" reality. Both rely on observations to collapse the wave function, and neither specifically calls out a conscious agent as necessary for an observation to occur. Observation is a measurement, whether intended and registered by a brain or not.
      • pdonis 11y ago
        > An observation collapses a wave function. Not if the MWI is true. Talking about wave function collapse presupposes that the Copenhagen interpretation is true. In the MWI, there is no collapse; it's unitary evolution all the time.
    • 11y ago
• deleted 11y ago
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• deciplex 11y ago
  John Wheeler's delayed choice thought experiment was already confirmed in the lab over ten years ago. It's neat that they were able to get results with baryonic matter, and it was definitely worthwhile to try to do that, but this article seems to be implying that the results could have been anything else than what they were, or that there is new physics here, and is wrong on both counts. Also the deference to the Copenhagen interpretation is annoying - it's wrong. What they've observed is a consequence of how decoherence works, and 'observation' has nothing to do with it. Not faulting the researchers on this but seriously, it's time to stop talking about mythical 'observation' as though it's some integral part of quantum theory.
• sown 11y ago
  What does this mean? If there was a supernova eons ago in another galaxy and I'm the only human who had been hit by a cosmic ray, does that mean it didn't exist or happen until ... ? Does measurement have to include an agent? Could measurement mean interaction with other atoms?
  • photonic29 11y ago
    >Does measurement have to include an agent? Could measurement mean interaction with other atoms? Indeed it can. Roughly put, if information about the state left the undetermined system, a measurement has been made. One of the most frustrating interpretations of literature such as this is the idea that there is something spooky, special, and reality-making about a conscious mind. Lots to think about there philosophically, but the physics happens at lower levels of abstraction.
  • matt_kantor 11y ago
    The trouble with questions like yours is that we're the ones asking them. The results of an unobserved measurement cannot be known, so there's no way to completely remove agency from our experiments. Personally, I think the simpler and less egocentric view is that all measurements produce wavefunction collapse, even when there's nobody looking. See https://en.wikipedia.org/wiki/Von_Neumann–Wigner_interpretation https://en.wikipedia.org/wiki/Von_Neumann–Wigner_interpretat... and https://en.wikipedia.org/wiki/Measurement_problem https://en.wikipedia.org/wiki/Measurement_problem if you want to read more.
• Rapzid 11y ago
  Is it not possible that it could have been observed no other way? Is observation driving the behaviour or behaviour driving the observation(or an external factor driving both)?
• A_COMPUTER 11y ago
  If I'm standing here, all the stuff that the atoms in my body could conceivably interact with have to be backfilled for me to interact with them according to this experiment, but since I'm not special to the universe, atoms three billion light years over, they are still interacting with each other, just not with me. So am I decohered to them? Is this like a divergent timelines theory such that coherence is defined as when different possibilities converge while following possibilities, reducing them and then so must necessarily collapse as other possibilities drop off? So what's the difference between cohered and decohered reality then? It sounds then like it would just be one of those paths, the one that we happen to be on that we only notice because we're conscious so that's our arbitrary (to the universe) observation point. That's the only way I can make sense out of this without attaching significance to human observation.
  • mjfl 11y ago
    The philosophical interpretation of Quantum Mechanics is a very hard, unsolved problem. There are many reasons why quantum mechanics is theoretically good and philosophically terrible, and not just in a subtle, esoteric way. The reason is that in Quantum Mechanics there are 2 main types of entities: particles, "things" that evolve according to the Schrodinger equation, and "observers". Observers are what deliver to us the results of randomly sampling from the probability distribution defined by the squared amplitude of the wave function by "collapsing" it, according to the Copenhagen interpretation. However, there is no particle that acts as an observer, they all just follow the Schrodinger equation, but nothing that exists isn't a particle. How could "observers" exist and interact with particles then? The Copenhagen interpretation is philosophically terrible. And it really pisses me off that this article title seems to hint that they've really confirmed it. In a lab, an experimenter can just point to his apparatus and say, "that's the observer". Or, being more formal, they can say a thermodynamically irreversible process plays the role of an observer. But this is not really a satisfying explanation because how could it be possible to generate these large, discontinuous motions we call "collapse" on the macroscale if it is impossible on the microscale? There are the multiverse theories that you seem to describe, but they have their own problems. Rae's Quantum Physics: http://www.amazon.com/Quantum-Physics-Illusion-Reality-Classics/dp/1107604648/ref=pd_sim_14_1?ie=UTF8&refRID=1QMSE7ANN5CFTEC7XAEZ http://www.amazon.com/Quantum-Physics-Illusion-Reality-Class... goes over a lot of them without getting to messy in the math. Other interpretations of QM are in the book as well. There are many: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec...
• vectorpush 11y ago
  armchair musings of a layperson physicist/philosopher follow: the non-interference pattern is the optimized result of a deterministic universe that requires the observation to occur. The measurement didn't reach back in time, the results were specifically determined by the same causal chain that determined an experiment would be performed.
• javert 11y ago
  Or we just don't undestand the next level down. This "reality doesn't exist until it is measured" business is utterly reprehensible. It is masturbatory science/journalism.
• hackinthebochs 11y ago
  Let us not forget about Pilot-Wave theory, where it has both particle and wave-like properties simultaneously. In fact, I don't quite get why people are so enamored by these fanciful interpretations when Pilot-Wave is so much more down-to-earth.
  • madaxe_again 11y ago
    I came here to say the same thing - this behaviour is readily explained by a pilot wave formulation of QM, and requires no spookiness. Increasing number of physicists are re-evaluating Bohm and De Broglie's work - I for one think we've been down a 60 year dead-end, which has yielded models, but no plausible mechanism.
    • orbifold 11y ago
      I'm fairly certain that you would have a very hard time extending pilot wave theory to Quantum Field theory, although who kowns, maybe it is possible.
      • madaxe_again 11y ago
        It can be - did a graduate paper on the topic some years ago, looking at it through the Dirac sea - and appears others are taking an interest in the topic too - here's a nice paper which gives a good overview: http://iopscience.iop.org/1742-6596/306/1/012047/pdf/1742-6596_306_1_012047.pdf http://iopscience.iop.org/1742-6596/306/1/012047/pdf/1742-65...
  • ilitirit 11y ago
    I'm not really qualified to talk on a technical level about the matter, but besides the distaste some people have for Aether Theories, there are other reasons some scientists don't like PWT, especially as it's demonstrated by the behaviour of oil droplets. The physical, conceptual differences between any quantities describing droplets on one side and the wave function on the other side are clear. The former are observable – you may actually measure what the shape of the droplet looks like; you can't measure the wave function by any apparatus, at least not in a single repetition of the experiment. The former has an objective interpretation; the latter has a probabilistic interpretation, and so on. The wave function just encodes all the probability distributions for actual observables – but the wave function isn't and can't be one of them. http://motls.blogspot.com/2014/07/droplets-and-pilot-waves-vs-quantum.html http://motls.blogspot.com/2014/07/droplets-and-pilot-waves-v...
• hkailahi 11y ago
  In the time of Empiricism, the philosophers George Berkeley and John Locke proposed something similar. I believe it was called it immaterialism, or the idea that nothing exists without being perceived. Berkeley went further saying that objects only exist in the mind, or something like that.
  • fragsworth 11y ago
    They're not saying "nothing exists without being perceived", because the probabilities of things at the quantum level all do exist. It seems sort of unfortunate that physicists would call these quantum probabilistic behaviors "not reality", because they are just as real as anything else.
    • hkailahi 11y ago
      Right I'm aware of that. I just thought it was an interesting parallel. Locke based his works off of the physics known at the time (Newton, etc). His theories were later definitely refuted by advancements in physics. Though it wasn't his intended meaning, it is interesting at least to see similar language being brought back by physics.
  • a_e_k 11y ago
    One of my favorite authors, Jorge Luis Borges, wrote a short story, "Tlön, Uqbar, Orbis Tertius," based on Berkeleyan philosophy. I thought again of this passage when I read the headline: "Things duplicate themselves on Tlön; they also tend to grow vague or 'sketchy,' and to lose detail when they begin to be forgotten. The classic example is the doorway that continued to exist so long as a certain beggar frequented it, but which was lost to sight when he died. Sometimes a few birds, or a horse, have saved the ruins of an amphitheater."
  • _0ffh 11y ago
    There's a fun Limerick by one Robert Knox inspired by one of Berkeley's arguments about what happens to objects when they are not being perceived: There was a young man who said, "God Must think it exceedingly odd If he finds that this tree Continues to be When there's no one about in the Quad." REPLY Dear Sir: Your astonishment's odd: I am always about in the Quad. And that's why the tree Will continue to be, Since observed by Yours faithfully, GOD. Edit: Formatting (newlines)
• sosuke 11y ago
  If you could change how you measure it, could you change your reality?
  • deleted 11y ago
    [deleted]
• dazlari 11y ago
  So a bear doesn't sh*t in the woods.
  • ceejayoz 11y ago
    The bear itself is an observer, though.
• leeleelee 11y ago
  Most of these articles / experiments focus on the perspective of being the observer... What is the conclusion if you are the thing being observed?
• rasz_pl 11y ago
  maybe time is not a one way street
• hasenj 11y ago
  I'm not familiar with this particular experiment, but all my pondering on the subject - as a layman - leads me to a simple conclusion. The properties these experiments are measuring are simply bogus. They are not well defined. The answer that comes out is not some intrinsic property of the "particle", but the result of the environment in which the particle interacted with the "measurement" system, so to speak. The particle has some other properties, but what's being "measured" is not one of those properties. How can I explain? Imagine someone who has never tried any Korean food, and you try to ask him/her: what's your favorite Korean food? There's no answer. So you try to "measure" it by feeding him some Korean items and recording his facial expressions. He will like some items more than others, but it has nothing to do with "his favorite Korean food", and has more to do with how the items were prepared and his mood at the time. A "point" location for a photon is never defined; it's not a property of a photon that it exists in a point in space. When you fire a photon at a "wall" and see a "blip", you're not seeing the position of the photon at some point in time. You're seeing the rough position of the atom that had an electron that absorbed the photon's energy, and I'm not even sure the atom has a well defined point position either. The whole thing is an artifact (a side effect) of some interaction between several systems and doesn't really tell you anything fundamental about the photon (or the quantum object). At least that's how I understand it.
  • FranOntanaya 11y ago
    Intuition tells me this is like saying a droplet of water can both be a sphere and a single point because it'll pass through several holes on a net, but capillary action makes it collapse into a needle.
  • ilitirit 11y ago
    https://en.wikipedia.org/wiki/Hidden_variable_theory https://en.wikipedia.org/wiki/Hidden_variable_theory
    • hasenj 11y ago
      When people talk about hidden variable theories they still assume a definite answer exists. I'm saying the answer doesn't exist because the question is not really valid in some sense. Which kind of coincides with the idea that "the observable doesn't exist until measured", but I'm taking a little further and saying, it doesn't exist even when "measured" because you're not really measuring the thing you think you're measuring.
• zw123456 11y ago
  And perhaps someday we'll get to meet the great programmer in the sky the developed the simulation we are living in and we will ask him why he designed it that way and he will say something like "oh I just wanted to optimize the code so I simply excluded reality subroutines when there were no beings looking. I just never thought you guys would notice. As soon as I saw that you guys noticed the flaw, I was going to load a patch but then the confusion it was causing with the simulated beings became interesting and so I just left it in as an accidental feature of the game." Meh, but probably not.
  • yummybear 11y ago
    Reality frustrum culling?
    • paraiuspau 11y ago
      ^ This
      • hagmonk 11y ago
        I kind of love the idea that it's an optimization because the universe would have a shitty frame rate if light's quantum state wasn't lazily evaluated based on whether anyone's viewport was aimed at it.
  • stingraycharles 11y ago
    In other words, reality is lazily evaluated and is written in Haskell ?
    • reinhardt 11y ago
      Not really, most of it is just hacked together with perl: https://xkcd.com/224/ https://xkcd.com/224/
      • shiggerino 11y ago
        Perl 6 has lazy evaluation, doesn't it?
• jen729w 11y ago
  Deepak Chopra is going to have a field day with this one.
• sravfeyn 11y ago
  For us, Reality by definition, is what we perceive. Our mind/brain/consciousness interprets the perceptions, draws conclusions makes up reality by interfacing an Electromagnetic medium. When trying to explain Popular Quantum Physics, one should avoid using the word Reality loosely.
  • sooheon 11y ago
    I think most people's definition of reality would be precisely not that it "is what we perceive", in that two people can and often do perceive the same underlying reality differently. That there is an underlying reality at all may be an incorrect assumption, but it is the intuition most people have.
• facepalm 11y ago
  "If one chooses to believe that the atom really did take a particular path or paths then one has to accept that a future measurement is affecting the atom's past, said Truscott." Is that equivalent to "reality doesn't exist until it is measured"? Because I don't see the latter claim (which is the headline on HN) anywhere in the text? Also, didn't Feynman explain in q.e.d. that it's not either a wave or a particle, it's always a particle and the probabilities for the path the particle takes behave like waves? (Something like that, I am foggy on the details).
• omarchowdhury 11y ago
  Who or what is measuring all of the quantum building blocks that collectively sustain and comprise the total universe?
• ghosthamlet 11y ago
  There is no reality at all, like 3D cgi, if no man see it, it will not be calculated, so no exists. It means another experiment: we living in a computer-simulation, http://www.telegraph.co.uk/news/science/science-news/10451983/Do-we-live-in-the-Matrix-Scientists-believe-they-may-have-answered-the-question.html http://www.telegraph.co.uk/news/science/science-news/1045198... http://www.huffingtonpost.co.uk/2012/10/11/physicists-may-have-evide_n_1957777.html http://www.huffingtonpost.co.uk/2012/10/11/physicists-may-ha... http://news.discovery.com/space/are-we-living-in-a-computer-simulation-2-121216.htm http://news.discovery.com/space/are-we-living-in-a-computer-... http://listverse.com/2013/12/02/10-reasons-life-may-be-a-computer-simulation/ http://listverse.com/2013/12/02/10-reasons-life-may-be-a-com... http://io9.com/5799396/youre-living-in-a-computer-simulation-and-math-proves-it http://io9.com/5799396/youre-living-in-a-computer-simulation... http://www.nature.com/news/simulations-back-up-theory-that-universe-is-a-hologram-1.14328 http://www.nature.com/news/simulations-back-up-theory-that-u... http://thelaymansanswerstoeverything.com/2013/01/scientific-proof-we-live-in-a-simulation/ http://thelaymansanswerstoeverything.com/2013/01/scientific-...
• ghosthamlet 11y ago
  http://www.simulation-argument.com/simulation.html http://www.simulation-argument.com/simulation.html says: at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a “posthuman” stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation. It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation. A number of other consequences of this result are also discussed. COMPUTER SIMULATION vs HOLOGRAPHIC UNIVERSE http://www.crystalinks.com/holographic.html http://www.crystalinks.com/holographic.html http://thelaymansanswerstoeverything.com/2013/01/scientific-proof-we-live-in-a-simulation/ http://thelaymansanswerstoeverything.com/2013/01/scientific-...
  • exch 11y ago
    What does 'post human' mean? Unless we go extinct, we will always be humans, regardless of what species we evolve into. Our current species is "Homo Sapiens Sapiens", not "Human". Ergo, if we evolve into amorphous blobs of space goo, we will still be Human but not "Homo Sapiens Sapiens". Which means it is physically impossible for us to ever reach a "post-human" stage.
    • ceejayoz 11y ago
      I'd say you'd be posthuman if a current human wouldn't recognize you as being part of the same species. https://en.wikipedia.org/wiki/Posthuman https://en.wikipedia.org/wiki/Posthuman
  • eli_gottlieb 11y ago
    Proposition (2) is just flagrantly, blatantly bullshit. The amount of computational power needed to simulate even just the bits of the universe we conscious humans happen to be observing at any one time is so stupendously humongous that you'd get more utility out of repurposing your cosmic-scale computers to play video games.
• flowctrl 11y ago
  The press around this experiment uses misleading language that leads people like Deepak Chopra to think that we create reality through consciousness. It has nothing to do with consciousness. This article explains it: http://theness.com/neurologicablog/index.php/more-quantum-weirdness/ http://theness.com/neurologicablog/index.php/more-quantum-we...
• VonGuard 11y ago
  Reality is just a giant whirling layer of infinite View Master-like multidimensional slides, overlaid one upon the other. Every slide locks into place to be seen as we are looking in whichever direction, at whatever time. I'd wager time travel is never discovered by humanity, but that some sort of time or dimensional goggles are created, eventually. Essentially, we're all watching our own multi-dimensional, multilayer, composite TV channels and seeing shadows of each other across our screens. Allegory of the Cave meets 3D Ray Tracing and such. That's nothing, though. Not compared to the realization that every face is a mirror, and we're all stuck here until we can treat each other as ourselves. Maybe it's not true, maybe it's insane ramblings. But it does explain the crazy doods muttering to themselves on the corner and those people in your life who "just aren't watching the same channel as the rest of us." Like me!
  • brador 11y ago
    But time may just be a human construct.
    • VonGuard 11y ago
      Absolutely! As is perspective. Time just translates to a whole series of indexes for which planes of existence, in which dimensions are aligning into the measuring perspective. It's the pointer for some such reflection, and angle to see it. Those planes of existence are these slides I mention. Whirling in time and subject, but always a representation of some spherical center whole that is the perspective of another. We're all just holes looking into this swirling miasma of time/space/parallel-dimensions/etc, seeing shadows of holes.
      • brador 11y ago
        You are assuming a multidimensional universe. There may just be a single dimension, with just a now, a single state solution, t=1, d=1. But physicists like to ignore that solution because it doesn't get the juicy book deals.
  • jules 11y ago
    > it's insane ramblings Exactly. I'd recommend the other 100 commenters or so who posted a similar reply to learn some basic quantum mechanics. Contrary to popular belief it's not that hard if you have a grasp of math.
• rrodriguez89 11y ago
  But , who was measuring before the big bang , and the millions of year before we appear ? what is so special about measurement? I thought that our brain was merely a quantum computer ?
• OscarCunningham 11y ago
  The jokes above that say that this was done by our simulators to save on computation are amusing but wrong. Quantum computation is famously harder than classical computation.
  • LoSboccacc 11y ago
    unless you have a quantum computer then it's still hard but you can evaluate all states concurrently and trick them to collapse into the result
  • AgentME 11y ago
    That's assuming that the simulation is running on classical computers. The simulation could be running on quantum computers or who-knows-what. Quantum computers might not be so inconvenient to build to make in the host world's physics.
• scotty79 11y ago
  For me the only way I can make wave-particle duality and associated observations believable is to think that light and similar entities always travel as a wave, but sometimes interact like particles. This understanding is in line with this experiment without believing that future affects the past. It's just that atom is never a particle until it reaches detector at the end. Only there it displays ability to exchange momentum with one other single atom as if two billiard balls hit. Throughout the whole experiment it travels as a wave, both paths, grating or no grating. It just either interferes if there was second grating or not if there was no second grating.
• amelius 11y ago
  QM explained by a software engineer: https://m.youtube.com/watch?v=dEaecUuEqfc https://m.youtube.com/watch?v=dEaecUuEqfc
• obstbraende 11y ago
  Quantum Bayesianism [0] treats such effects explicitely as Bayesian belief updates of the experimenter. This leads to an interpretation of quantum mechanics free of such paradoxical/counterintuitive statements about reality. I'd like to hear other physicists' opinions on minority interpretations like this. [0] layman-friendly article / interview: https://www.quantamagazine.org/20150604-quantum-bayesianism-qbism/ https://www.quantamagazine.org/20150604-quantum-bayesianism-...
• davej 11y ago
  I find it fascinating how the speed of light, quantum indeterminacy and Planck's length could all be seen as allegories for computational optimisations in a simulated universe. This is something that I've thought about for some time, I posted a question about this a number of years ago on Reddit: http://www.reddit.com/r/Physics/comments/g287k/quantum_indeterminacy_a_computational/ http://www.reddit.com/r/Physics/comments/g287k/quantum_indet...
• DavidPlumpton 11y ago
  The Many Worlds Interpretation explains all of this quite intuitively http://lesswrong.com/lw/r8/and_the_winner_is_manyworlds/ http://lesswrong.com/lw/r8/and_the_winner_is_manyworlds/
• db48x 11y ago
  Just remember that in quantum physics, any interaction between two particles is a measurement.
  • Gravityloss 11y ago
    Something like this should be the top reply for every "quantum weirdness" Hacker News link. Schrödinger's cat thought experiment was meant to highlight the absurdity of stochastic thinking by taking it to the extreme, not as a description of reality. https://en.wikipedia.org/wiki/Quantum_decoherence https://en.wikipedia.org/wiki/Quantum_decoherence
• agd 11y ago
  > "At the quantum level, reality does not exist if you are not looking at it" So much physics reporting mistakes science for philosophy. It leads to so much confusion among laypeople.
• azinman2 11y ago
  Best headline ever.
• wanda 11y ago
  > Reality is a computer program I'd like to issue a pull request..
• dschiptsov 11y ago
  So, the Sun doesn't exist when experimenter is unconscious? I see. It seems like at least Philosophy 101 should be mandatory to quantum physicists.) Reality doesn't depend on an observer (who distorts it by his observation). Reality just is. There are light and other temporary states of what we call "energy". That's it. Time, space, relativity are human concepts - the hard-wired modes of perception which conditions our experience. From a Photon's perspective none of these exist.
  • jimhefferon 11y ago
    > at least Philosophy 101 should be mandatory to quantum physicists Or perhaps quantum physics should be mandatory for Philosophy 101?
  • phaemon 11y ago
    Photons can't have "temporary states" because photons don't experience time. That's where the word "temporary" comes from, the Latin "tempus" meaning "time".
• Ygg2 11y ago
  Um, this doesn't prove reality doesn't exist until it is measured. It just proves that measuring and "decision" which state to appear in happens simultaneously. It could mean that time on quantum scale doesn't differentiate past/future.
  • david927 11y ago
    Sure it does because, while certainly quantum scale doesn't carry the same sense of time, we do. Everything we see, what we call reality, is made up of the Lego blocks of electrons, protons and neutrons, and yet even at that level it makes no sense to talk in concrete terms about, say, an electron's spin. We would expect that the spin exists and we find out what it is when we measure it, but it's not that. It's that talking about its spin is meaningless until you measure it. What you can reason about the Lego blocks of everything we see, smell, touch and taste, what gave birth to us and what will kill us, is indescribable until it's asked to be described. Whether that's because it's locked-in to time or not is irrelevant because it means the same thing: reality is not there until it's there.
    • Ygg2 11y ago
      You can only conclude that "Physical reality doesn't exist until observed", if you imply nothing can move faster than light. Also hidden variable theory aren't yet categorically disproven. A fractal theory could explain why we keep getting different results when measuring reality in different ways.
      • david927 11y ago
        I will happily imply that energy/mass cannot move faster than light. You know, I think a hidden variable theory is a crutch. To me, there's simply a Planck's constant foundation that prevents infinite regression just as much in terms of information as it does with radiation, etc.
        • Ygg2 11y ago
          What you imply is besides the point. It's what the finding implies. Interpreting that as "physical reality doesn't exist" is far fetched.
• codeshaman 11y ago
  Which is another way of saying that reality is invented. "Measuring" is applying our sensors onto the external reality and producing a map of what is observed in the form of thoughts, ideas, imagery - 'perception'. But since the sensors are also part of reality, which does not exist before sensing it, it can be postulated that what is perceived is not a consequence of reality hitting the sensors, but the result of a new thought about reality being perceived, or simply - an invention. That is, reality (including your body, brain and you) is the product of a thought process, but (here's the interesting part) the thinker is you and not you at the same time, or rather - the thinker is you and every other being. That thinker is called God. Or Universe or whatever you want to call the thing or being that is the eternal recursive loop of self-invention / self-perception. Of course very hard to put into language, but easily grokked under psychedelics. It's interesting that science (and math) is slowly pointing towards this conclusion too, a thing that many great scientists arrived at intuitively.
  • CatsoCatsoCatso 11y ago
    Of course very hard to put into language, but easily grokked under psychedelics. Fantastic line.
• Strilanc 11y ago
  The linked article is titled "Experiment confirms quantum theory weirdness". Please don't exaggerate the title. These experiments do not show that "reality doesn't exist until it's measured". First, "realism" [1] is not the same thing as "reality". "Realism" basically means "physical quantities have a definite value". "Reality" is that thing that determines your experimental outcomes. Don't mix them up. Second, interpretations of quantum mechanics disagree wildly about what kind of weird you use to explain things. Some interpretations have "realism", some don't. Some interpretations have retrocausality, some don't. Some interpretations have FTL effects, some don't. Since all the interpretations give (mostly) the same experimental predictions, it's misleading to single one out and say just that particular brand of weirdness was confirmed. We confirmed that there's weird there. We didn't distinguish what brand of weird it is. Physicists widely disagree about which brand of weird to use, with no position achieving even a majority [2]. The original title was better. 1: https://en.wikipedia.org/wiki/Na%C3%AFve_realism#Realism_and_quantum_physics https://en.wikipedia.org/wiki/Na%C3%AFve_realism#Realism_and... 2: http://www.preposterousuniverse.com/blog/2013/01/17/the-most-embarrassing-graph-in-modern-physics/ http://www.preposterousuniverse.com/blog/2013/01/17/the-most...
  • yummyfajitas 11y ago
    I don't think the title is a misrepresentation of the article, just the physics: From the article: "It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it..." The article does appear to be (incorrectly) arguing that this experiment proves one interpretation of QM correct. It's definitely incorrect - some years back myself and others used non-experimentalist interpretations of QM to get the same result - but it's not a misrepresentation of the article.
    • Strilanc 11y ago
      Yes, the article does quote the physicist saying that. Physicists do say things like that, without adding caveats like "assuming the Copenhagen interpretation, which is the plurality opinion and my de-facto working theory day to day". But the article didn't include it in the title, and I think that was the right choice. And HN usually tries to keep the original title.
• deleted 11y ago
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• jondubois 11y ago
  I always found the notion that "If you measure it, it behaves differently" to be really confusing. When considering the double slit experiment - In both cases (whether we are observing the particle going through a single slit or otherwise observing the interference pattern left afterwards), we are in fact simply measuring 'observable effects' in both cases - It's just that we are measuring them in different ways. If you didn't measure both cases, you wouldn't be able to compare their outcomes. It seems that it is not about whether or not the event was measured/observed but about HOW and WHEN it was measured. In neither case do we actually 'witness it happen' - In both cases, we are just observing effects of those events. The light which allowed us to 'directly observe it' is as much a byproduct of the actual event as the interference pattern left behind on the surface.
• octatoan 11y ago
  Editorialized titles are irritating, random HN commenter says.
• dfragnito 11y ago
  "Truth" is ones version of Reality.
• sudioStudio64 11y ago
  It's too bad that this will be taken by Deepak Chopra fans as evidence that consciousness is magic.
• sebringj 11y ago
  no. https://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat https://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat and then... http://bigthink.com/dr-kakus-universe/physics-on-the-fringe-dr-kaku-answers-questions-from-viewers-of-the-science-channels-new-show http://bigthink.com/dr-kakus-universe/physics-on-the-fringe-... clears it up for me.
• derrickgrant 11y ago
  Guys I'm a total quantum physics noob but when I read this post I couldn't help but think of Alan Watts and the Taoist definition of the theory of time (quoted below). HN in your opinion how does this theory hold up to the to new finding (if at all)? Big thanks to anyone taking the time to humour me, I really appreciate your time. 'So when you have this happening the other illusion that a Westerner is liable to have is that it's determined in the sense that what is happening now follows necessarily from what happened in the past. But you don't know anything about that in your primal ignorance. Cause and effect? Why, obviously not! Ha ha ha! Because if you're really na•ve you see that the past is the result of what's happening now. It goes backwards into the past like a wake goes backwards from a ship.'
  • derrickgrant 11y ago
    Here's the full transcript of the Alan Watts lecture http://thinkyhead.blogspot.co.uk/2013/09/alan-watts-philosophy-of-tao.html http://thinkyhead.blogspot.co.uk/2013/09/alan-watts-philosop...
• hyperion2010 11y ago
  Ah, the old "now we have to figure out what 'measured' means." Thanks science journalists!