Hi Lorraine,

Thanks very much for reading my essay and for your comment.

I define an observer as a frame of reference. That is, a coordinate frame (to put it in the language of relativity), a causal patch (cosmology), or even a Boolean lattice (quantum logic). I would not consider a particle (or any group of particles up to and including living creatures) as an observer precisely because, once gravity is involved, the very definition of a particle depends on the reference frame (hence, for example, the accelerated observer sees Hawking radiation while the inertial observer does not).

All best,

Amanda

Dear Amanda,

(Replying down here because the subthread above got a bit long.)

I think Tom Banks starts with a lot more structure than I do... which might, incidentally, be necessary. The most obvious criticism of my ideas is that they may be too parsimonious to achieve sufficient explanatory power, but I do have some reasons to be hopeful that I can get somewhere worthwhile from this direction.

"Made of information" is a good description of my approach, although I wouldn't choose that terminology myself simply because it's already been used to describe a lot of theories that really involve a lot of auxiliary structures. The information is observer dependent, but not the laws of physics.

I have my doubts about a lot of aspects of recent black hole physics, simply because we know that it resides near the horizons of validity of the theories involved (no pun intended). I view it as worth taking seriously, and it's certainly worthwhile to explore the consequences, but I would not be surprised if certain aspects of it turn out to be artifacts of theory stretched beyond its bounds. Take care,

Ben

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Dear Amanda,

If you have found the time to read my essays you would note that our thoughts coincide apart from the different way of expression (due of my amateur education in physics). Each observer has his own reference frame and we can not examine any phenomenon taking two (or more) reference frames at the same time. However I propose that the deviating views by different observers is resemblance of their different frames and it does not mean a difference in Reality. It is like a view from an open window. Every observer has his own view that depends from his position and not to another Reality out of the window. Each observer can see a different part of the only one Reality because of his own position in relation to the window and the Reality out there.

The expression inside and outside of a Black Hole (BH) resembles mine real and virtual part in any universe. It is evidence that real observers can realize only the real part of their universe while the virtual observers only the virtual part. It is time however to try to resolve the rules of the virtual part of our Universe (if we consider ourselves as real observers).

During the BH's inhalation the information "lost" is transferred to a new universe which may be of different or the same dimensionality (hence the black holes' jets).

The quantum part of your essay can be related to World Line (WL) individuality of each event through spacetime that for many instances there are equivalent different paths close to the WL of events (see fig. 1).

Thank you for the "Experimental evidence of solipsism?" that is a straight evidence of NCS as well.

Best wishes, Ioannis

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Amanda -- Wow! I've read a lot of FQXi essays over the years, and this is one of the most interesting I've seen. One thing I didn't notice you tackling, though, was an explanation for the consistency among observations. I have an idea on that: The kinds of observers familiar to us -- biological and technological ones -- share a topological connection which makes inconsistent observations impossible. That idea is central to my essay, "Toward an Informational Mechanics," as is Rovelli's relational quantum mechanics (which I was thrilled to see you mention -- Rovelli just doesn't get enough love).

In my essay's comments section, there is some discussion about solipsism. I explained my thought that collective reality is a kind of "collective solipsism," but you're absolutely right that each observer frame corresponds to its own universe. It's just that topologically connected observers necessarily observe common informational features of the universe, and I think it is precisely this commonality and consistency that creates the appearance of a single universe. I hope you have a moment to check it out.

Great work again, and best of luck in the competition.

    • [deleted]

    Hello Ms Gefter,

    I beleive that you speak about the interpretations of this Universe. You know the Universe is the same for all.That said we perceive it with our own emotions correlated with our education. The universe is the same sphere for all. In fact I beleive that you cannot say so your conclusion about the universe. We cannot confound an interpretation with a pure determinism.

    Let's take a simple example.Imagine that you like the color of the planet mars, red. and that a friend , him does not like the red color of this planet. It does not mean that this planet mars does not exist or that it exists two planets mars for example.

    1+3+5+7+11+13=40 I don't see an other number :)

    Best Regards

      • [deleted]

      Dear Amanda

      in last issue of Russian magazine

      http://ufn.ru/en/articles/2012/9/

      you can read

      Letters to the editors

      "Einstein Moon"

      http://ufn.ru/en/articles/2012/9/h/

      It seems to me soliptic view.

      Dear Amanda.

      Your thesis first sounds shocking, as intended, but; 'the truth will first look wrong as it will be unfamiliar.' (Feynman) so it's in with a shout. I think you find much of the path to truth, but suggest you then drift off to hypothesise and question. I hope you may read my essay which suggests a direct mechanistic and deterministic path in a similar direction, and some causal answers to co-variance. This nevertheless agrees or has analogies with your views;

      "...we must never speak of more than one observer or universe at a time."

      the "...observer-dependence of the vacuum."

      "...multiverse cosmology will have to give way to a new kind of cosmology, one that is radically frame-dependent."

      "...it is equally valid to describe reality from any one of an infinite number of possible reference frames."

      "...each observer's reference frame defines a complete universe, and anything outside the frame is considered merely a redundant description"

      I agree your identification of the low quadrupole, 'axis of evil' and the other CMB anisotropies, to which a solution emerges (consistent with electron twin vortex spin). A consequential recycling mechanism is more referred in the end notes, last years essay and elsewhere. ("...the black hole evaporates and eventually blinks out of existence, presumably taking all internal information with it."). But then returns.

      A very well written, courageous and well argued essay. I really do look forward to your comments on the 'hard reality' analogies underlying the theatrical surface of mine.

      Very best wishes

      Peter

        Hi Karl,

        Thanks so much for your kind comment! I'm so glad you enjoyed the essay.

        The question of consistency among observations is a fascinating one. For me, the key insight comes from Rovelli and from the lessons of horizon complementarity: there is no view from outside the universe, no superobserver who can see across reference frames. That means that any time two observers "compare notes", the comparison is itself an ordinary quantum mechanical interaction. That is, if I compare my observations with yours, the act of comparison takes place within a single reference frame - mine or yours but never both simultaneously. There's no "view from nowhere" from which we can compare two observers' perspectives independent of a reference frame.

        I just had the chance to read your essay and I thought it was fantastic. I'll post some thoughts over on your page.

        Thanks again!

        All best,

        Amanda

        Hi Steve,

        Thanks for reading my essay and for your comment. I appreciate your view; however, the point that I was trying to make in my essay is that while common sense would suggest that we all live in a single universe and that different observers' perspectives are merely different descriptions of one and the same reality, the latest advances in theoretical physics suggest otherwise. That is, we can assume, as you do, that there is one single reality occupied by several observers, but in doing so we actually violate the laws of physics (we clone information, for instance). Put another way, the laws of physics only make sense within a single reference frame at a time. This, to me, is both shocking and profound.

        Best,

        Amanda

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        Amanda,

        Your thesis vitally depends on miraculous theoretical results like this one:

        "...Hawking particles objectively exist according to observers outside the black hole and objectively do not exist according to the unlucky observers who fall in."

        In my view, juggling with such results, without questioning the underlying assumptions, leads you nowhere. The miraculous results may simply be absurd consequences of false assumptions. Let me give examples of an opposite approach:

        Lee Smolin, The Trouble With Physics: "Einstein's special theory of relativity is based on two postulates: One is the relativity of motion, and the second is the constancy and universality of the speed of light. Could the first postulate be true and the other false? If that was not possible, Einstein would not have had to make two postulates. But I don't think many people realized until recently that you could have a consistent theory in which you changed only the second postulate."

        Joao Magueijo, Faster Than the Speed of Light: "Lee [Smolin] and I discussed these paradoxes at great length for many months, starting in January 2001. We would meet in cafés in South Kensington or Holland Park to mull over the problem. THE ROOT OF ALL THE EVIL WAS CLEARLY SPECIAL RELATIVITY. All these paradoxes resulted from well known effects such as length contraction, time dilation, or E=mc^2, all basic predictions of special relativity. And all denied the possibility of establishing a well-defined border, common to all observers, capable of containing new quantum gravitational effects."

        Pentcho Valev

          Hi Pentcho,

          I wholeheartedly agree that questioning our assumptions is crucial to make progress in physics - and of course that is the whole point of this essay contest!

          The "miraculous theoretical result" you refer to is very well accepted in the physics community. I have yet to come across any legit disproof of Hawking's calculation, which itself is based on the extremely well-tested equations of quantum mechanics and general relativity. Could Hawking turn out to be wrong? Of course. In the meantime, I think it's important to follow these profound theoretical discoveries to their logical limits and see where they lead. As I explain in my essay, I am further convinced by the convergence coming from physics as wide-ranging as quantum logic and the cosmic microwave background data.

          Thanks for your comment.

          Best,

          Amanda

          Hi Peter,

          Thanks very much for your comment. I look forward to reading your essay.

          Best,

          Amanda

          • [deleted]

          Hawking assumes the speed of light is constant in a gravitational field (and so contradicts both general relativity and Newton's emission theory):

          Stephen Hawking: "Both Mitchell and Laplace thought of light as consisting of particles, rather like cannon balls, that could be slowed down by gravity, and made to fall back on the star. But a famous experiment, carried out by two Americans, Michelson and Morley in 1887, showed that light always travelled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from. How then could gravity slow down light, and make it fall back."

          Stephen Hawking, A Brief History of Time, Chapter 6: "Under the theory that light is made up of waves, it was not clear how it would respond to gravity. But if light is composed of particles, one might expect them to be affected by gravity in the same way that cannonballs, rockets, and planets are.....In fact, it is not really consistent to treat light like cannonballs in Newton's theory of gravity because the speed of light is fixed. (A cannonball fired upward from the earth will be slowed down by gravity and will eventually stop and fall back; a photon, however, must continue upward at a constant speed...)"

          Do you agree with Hawking? Is the speed of light constant in a gravitational field? Did the Michelson-Morley experiment show "that light always travelled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from"?

          Pentcho Valev

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          Dear Ms Gefter,

          You are welcome.

          ps:The observation permits to improve the knowledges. The dynamics seem universal at all 3D scales. A hymenoptera(a bee) see the same dynamic with a pure relativity. If on an exoplanet, some intelligent creations see, they see the same relativistic dynamic of rotations of spheres. If a bird flies, so it utilizes the same physical laws, like made an airplane. In fact it is the same for all lifes in fact and all dynamics, so all rotations and motions implying rules of complementarity of evolution. The observations everywhere inside our universal sphere shall be always under the same universal dynamic of spherization in fact. The Universe is unique and bounded, with a specific universal equation of spherization of spheres.

          I beleive strongly that in fact the importance is to differenciate the philosophical interpretation(multiverse) and the pure realistic determinism of uniqueness and the correlated intrinsic laws(Universe).

          Fortunaly for our equations, laws, constants and SI :) furthermore. If not, we violate our laws, physical and universal of this homogene and intrinisic and bounded spacetime.

          Best Regards

          • [deleted]

          Thanks for this provocative and persuasive argument. The notion that reality may be observer-dependent by virtue of it being tied to perception which is necessarily user-specific leads me to wonder if what actually IS can ever be truly known. Also, I wonder if what actually is could be subject to the Hawthorne effect (from the social sciences, I think) whereby that which is being observed changes as a result of efforts to observe it. And then what?

          • [deleted]

          Dear Amanda,

          a very relevant, well written essay. Good luck.

            Dear Amanda:

            What a nice and provocative essay.

            I have one, very basic, question: For concreteness I will focus on the question of observer dependence of the notion of particles. If one looks at Unruh's calculation that gives a thermal spectrum of particles for the accelerated Rindler observer and no particles for the Minkowski observer isn't it true that the calculation starts from the same state in the same space-time for both these observers? While it is true that the two descriptions by the two observers are different it is also true that there is one description from which both of these can be derived.

            So why shouldn't I call this one description (Minkowski space R^4 together with vacuum state |0>) the one universe? If you want the description for a particular observer just tell me how she moves and I will tell you what she sees.

            I think what I said here for particles remains true for the other examples you cite (with the possible exception of quantum mechanics).

            All the best.

            Olaf

              Hi Olaf,

              Thanks so much for taking the time to read my essay, and for your great question.

              I agree with you that in the Rindler case, you can think about two observers that start in the same universe, then have radically different but equally correct views of that same universe (rendering particles observer-dependent). As you say, you can translate between them (with a Bogoliubov transformation rather than a Lorentz transformation). That alone doesn't obviously demonstrate the solipsism I'm arguing for, though the observer-dependence of the vacuum (with none being more "true" than another) is kind of the first clue that there is some degeneracy in the nature of the universe. But take the case of an elephant falling into a black hole. An accelerated observer outside the black hole will see the elephant burn up before it crosses the horizon, its ashes radiated back out to infinity. But an inertail observer who falls in with the elephant sees it alive and well inside the black hole before it hits the singularity. If you assume that these two observers occupy one single universe, then it's a universe in which the elephant's quantum state has been cloned, violating the laws of quantum mechanics. If you want to keep the laws of physics intact, you're forced to give up the notion of a single, shared universe and instead restrict to a single observer's frame. I suspect there's a way to make this same argument for a Rindler observer, but it's not as intuitive, since he can always stop accelerating, rejoin the inertial observer and compare notes. Nonetheless, while he is accelerating you would surely violate the laws of physics if you described both their points of view with a single global geometry. This becomes especially relevant when you consider that we live in an asymptotically de Sitter universe, and that each observer has their own event horizon.

              To my mind, this tells us something very powerful. That's not an original insight - I am taking cue from Susskind, Bousso, Banks, etc. Banks in particular argues that we have to generalize this argument to say that physics only makes sense within a single causal patch and that everything outside that observer's horizon should be considered pure gauge. What's original (and undoubtedly controversial!) in my piece is the attempt to connect this view with the low quadrupole in the CMB and with quantum logic.

              Thanks again.

              All best,

              Amanda

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              With not long to the end of community voting your consideration of my own would be very much appreciated. Kind regards Georgina.