Essay Abstract

Cosmology is the study of the origin and evolution of the universe - the one we all love and inhabit. In this essay, however, I argue that the basic assumption of a single universe shared by multiple observers is wrong. Synthesizing the implications of black hole radiation, horizon complementarity, dark energy, observations of the cosmic microwave background and quantum logic, I argue that moving toward a true theory of quantum gravity will require us to give up the notion that we all share the same universe. Instead, I argue, each observer has their own universe, which constitutes a complete and singular reality.

Author Bio

I am a science writer, consultant for New Scientist magazine and 2012-13 MIT Knight Science Journalism Fellow. I have a master's degree in the philosophy and history of science from the London School of Economics.

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  • [deleted]

Amanda

I am agree with you and Max Born.

Max Born, "My Life & My Views" 1st Edition

"The average person does not realize that there is no way to verify whether his personal view (that tree green, etc.) the same as the view (on the same tree) from another person, and that the word "the same "is not there any sense."

    • [deleted]

    Ms. Gefter,

    Hi. I think this is a good essay because it deals with the important topic of how different observers in different reference frames might view reality. I've been trying to point this out as well. For example:

    1. In my last FQXi essay and in a posting at my website, I try to show that a finite observer within an infinite set of finite balls might view each ball as an integer. But, a hypothetical, infinite-sized observer outside this set would not be able to see the boundaries of each of these balls (because they're infinitely small relative to him) and so the set would appear to him to be smooth and continuous.

    https://sites.google.com/site/ralphthewebsite/filecabinet/infinite-sets-ii

    2. The view of the absolute lack-of-all as "nothing" or "something" depends on how you think about this lack-of-all. That is, maybe, "something" and "nothing" are just different descriptions of the same thing. It's just that these descriptions are made by observers thinking about this same thing differently.

    https://sites.google.com/site/ralphthewebsite/filecabinet/why-things-exist-something-nothing

    Anyways, good essay!

      4 days later

      Dear Amanda: It was Yuri who made me attentive to your (well written) essay, and indeed there are paralels which does not mean crossing points. You would perhaps also be interested in reading "THE CONSCIOUSNESS CONNECTION", where your "observer's unique de Sitter horizon" is treated as the "Subjective Simultaneity Sphere" but not in the same way, because the radius of my SSS can change. I also have a solution for the so called "solipsism" by introducing the cutting circles of the SSS's that are forming Objective Simultaneity, this process is also called "decoherence" and qo forms the "history" of our universe.

      hope to meet you on my thread.

      and good luck in the contest.

      Wilhelmus

      Dear Amanda,

      I really enjoyed your essay. It is one of the most thorough and clearly focused contributions on the subject of covariance (i.e. observer dependence/independence) in the contest. I share your deep interest in this important subject. A few itemized remarks:

      1. One of the most important points, in my opinion, is the absolutely crucial role of spacetime structure in constraining "particle states." As you point out, such states arise in Minkowski spacetime via the representation theory of the Poincare group, and altering (or removing) this background changes the picture completely. Many approaches to quantum gravity involve very complicated spacetime microstructure, and this makes the use of covariance in the form of spacetime symmetry to determine particle states problematic even locally. There is another possible interpretation of covariance, however, and this interpretation is much more general than group symmetry. It is based on order theory, and is related to the relativity of simultaneity. In this interpretation, different frames of reference are, in general, no longer related by a group action, but by different refinements of the causal order. I describe this in more detail in my essay here: On the Foundational Assumptions of Modern Physics.

      2. You discuss several different types of horizons (black holes versus cosmological horizons, etc.) I'm probably preaching to the choir here, but there is some disagreement about the equivalence of different types of horizons and the implications for observer independence. There is an essay by Tanmay Vachaspati in this thread called "Preferred observers in quantum gravity" that discusses this and may interest you... along with yours, it was one of the more interesting submissions on covariance.

      3. You mention Rovelli's relationism; if you look at my essay you'll see that I have a lot of sympathy for this point of view. You might be interested in some of the submissions here on that topic; for instance Jorge Pullin's essay on the measurement problem.

      I particularly appreciate your broad point of view and synthesis of several different problems that are usually considered separately. Take care,

      Ben Dribus

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        Hello thinkers,

        Indeed but the determinism is the determinism. We can have indeed different points of vue, that will not change the universal determinism and its evolution spherization. In fact an apple is an apple. An flower is a flower, a paraticule also, and this and that, a star, a planet, a water drop, a wave,this or that, brains, eyes, hands, in fact the mass is the mass and we perceive it with relativity but the mass is the mass, and the light is the light. We contemplate just due to these two main gauges, the m and the hv. a photon is a photon, with its serie of uniqueness.So we can interpret diffrently but the Universal3D sphere is the same for all in a pure physical coherence of course. All roads do not go to Roma at my knowledge, so the determinism is an essential parameter permitting to sort the bad convergences.

        It is a simple evidence of our universality in evolution. We arrive at the uncompleteness due to our relativistic limits of understanding and perception of all the 3D scales.

        It is important to make the difference between our limits, physical, deterministic and rational, and the bizare hidden variables, irrational. The real understanding of this uncompleteness is in accepting opur young age at this universal scale. The time like a pure constant of evolution, duration implied by the rotations of spheres at all scales !

        Best Regards

        Hi Ben,

        Thank you so much for your encouraging and insightful comments. I'm so glad you share my interest in the profound significance of covariance and observer-dependence/independence. The history of physics seems to suggest that separating the invariant from the observer-dependent is the key to getting at the true reality beneath, and I'm fascinated by the ways in which quantum gravity undermines invariances that even relativity and quantum mechanics had left intact.

        With regard to your comments:

        1. I agree that the question of how to define global or even local observables in quantum gravity is extremely important and mysterious. Personally I am intrigued by the notion that while for AdS or asymptotically flat spacetimes you can retain some kind of invariant boundary observables, you can't seem to do so in de Sitter space, precisely because the de Sitter boundary is observer-dependent. This to me is suggestive that reality is far more observer-dependent than it seems.

        I've just read and greatly enjoyed your eloquent essay - though I think I'll have to read it a few more times to understand it! (That's a reflection of my nonexistent mathematical background, not of your essay!) I'm curious if it is in any way related to Tom Banks's work on holographic spacetime? As I understand it, he argues that the causal structure of spacetime can be reconstructed from quantum commutation relations up to a rescaling of lengths and times, and then you can use the holographic principle (because it gives you an area as a function of the number of quantum states) to include scale and now you've got spacetime structure. I believe in his work the observables are noncommutative matrices on the boundary of each "reference frame". Sorry if that's totally irrelevant. In any case, I'm in full agreement that the manifold won't survive quantum gravity - the dualities of string/M-theory certainly point in the direction of a kind of emergent spacetime. In your model, with its basis in binary elements, would you say that the world is "made of information"? And is that information observer-dependent?

        2. You're absolutely right - I probably should have mentioned that there is disagreement about how much we can extrapolate the lessons of black hole horizons to cosmic horizons; even Susskind himself has gone back and forth over whether horizon complementarity applies to the de Sitter horizon. Personally, however, I'm unconvinced by arguments that they shouldn't be treated equally. They are mathematically equivalent, they share the same properties of entropy, temperature, etc... yes, there are physical differences (the dS space doesn't "evaporate away", etc) but it just seems to be telling us something general and profound and as a structural realist I see every reason to treat them as equivalent - not least of all because of the equivalence principle!

        Thanks again for your comments and for your fascinating contribution, which I will now go and re-read :)

        All best,

        Amanda

        • [deleted]

        What is your opinion about my essay?

        http://fqxi.org/community/forum/topic/1413

        • [deleted]

        Amanda

        i think you are reincarnation from George Berkeley

        http://en.wikipedia.org/wiki/George_Berkeley

        Hi Yuri,

        Thanks - I take that as a compliment! However, the solipsism I'm talking about is not a kind of Berkeleyean idealism. I'm not arguing that everything exists only in the mind; in fact, I'm not talking about "minds" at all, but merely reference frames or causal patches. The "solipsism" lies in the fact that, according to some exciting new ideas in theoretical physics, each reference frame defines its own unique yet objectively existing universe. Covariance demands that we can talk about reality equally well from any frame, but the holographic principle and horizon complementarity demands that we restrict our description to a single frame at a time.

        All best,

        Amanda

        • [deleted]

        Thank you. Very interesting comment.

        Have you read my essay?

        http://fqxi.org/community/forum/topic/1413

          • [deleted]

          Dear Amanda,

          you may have a look to my essay (and rate it). It is related to many aspects with yours.

          Ioannis

            • [deleted]

            Hi Amanda,

            I thought your essay was very well written and clearly argued.

            I have two questions: What is an observer - a particle, an atom, a molecule, a cell or a larger living thing like a human being? If a particle is a type of observer with its own reference frame, would a molecule or a cell etc. be viewed as a type of composite reference frame?

            Lorraine

              Hi Yuri,

              I enjoyed reading your essay. I must admit I did not fully understand it, but you seem to be drawing some interesting connections.

              All best,

              Amanda

              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

              • [deleted]

              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

              • [deleted]

              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.