Cosmic Solipsism by Amanda Gefter

Amanda Gefter

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

Amanda Gefter

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

[deleted]

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

Amanda Gefter

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

[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

Amanda Gefter

Hi Peter,

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

Best,

Amanda

[deleted]

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.

Amanda Gefter

Thanks very much!

[deleted]

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

Olaf Dreyer

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

Amanda Gefter

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

Philip Gibbs

This is a very original and thought provoking idea, good luck.

[deleted]

Did you rate my essay?

Frederico Pfrimer

Dear Amanda

Very interesting essay! Thanks for the suggestion! Now I could for the first time understand some of the basic ideas about the problem of information in black-holes. But I have a question, if the universe is not shared by all the observer, what is shared by all observers?

I have some ideas about it that can possibly give you some insight, well I hope so... One of the main problem was that apparently there was information being cloned if you look from to observers at the same time. However, there should be some correlation between any two observers. In this case, the total entropy (or information) will not be the sum of each observer's entropy. Actually I think two observers are completely correlated such that their total entropy equals each one' entropy. This might explain why "we can never speak about more than one at a time." and also why "according to which each observer's reference frame defines a complete universe, and anything outside the frame is considered merely a redundant description.". In information theory, if you add a redundant description the information content is not increased!

I also agree that the existence of more than one reference frame can lead you to non compatible Boolean logics, each frame has a Boolean logic but the comparison cannot be done using a Boolean logic. But I think this notion is different from the notion of quantum mechanics. I mean, your ideas add something new to quantum mechanics (general relativity reference frames and observers), so they cannot be explained by pure QM, we'll need something new, probably quantum gravity or quantum general relativity.

Wish you all the best! And good luck on this contest!

Frederico

Wilhelmus de Wilde

Dear Amanda,

I liked very much your New Scientist article about mathematics and reality, especially the part about the dodecahedron, it is our consciousness but not in our reality. Tegmaark has some points, especially with the limits of our causal universe and the math's that go untill these limits, it is furtheron that our consciousness takes over and goes ad infintum.

It was Benjamin Dribus who draw again my attention on your essay (I posted before (september 10) in a post on [link:fqxi.org/community/forum/topic/1370] my thread [/LINK] , regarding the aspect of subjective reality that we both are treating.

I understand you are very busy, but perhaps you will find a split moment to read and or rate (or comment) my participation.

best regards

Wilhelmus

Conrad Johnson

Hi Amanda -

I came across this paper today. It's too technical for me, but if you haven't already seen it I think you'll be interested in the introductory section -- as a way of thinking about how the different universes of different observers are connected.

The Principle of Relative Locality

Conrad

Wilhelmus de Wilde

Dear Amanda,

The New Scientist special issue "WHAT IS REALITY" is very good, the perceptions of Henry Stapp and Matthew Donald have a lot of paralels with my own perception of reality.

I would like to sent my essay to them, is it possible that you give me their e-mail ,

mine is

wilhelmus.d@orange.fr

If not possible, I understand, but a question is always possible.

Thanks

Wilhelmus

pjackson

Amanda,

I'd like to pass you a link to the paper I referred above with strong analogies to your work, if you have time to read it and discuss.

I hope you manage to read my essay first as I look forward to your comments.

Best wishes

Peter

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