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Undecidability, Uncomputability, and Unpredictability Essay Contest
December 24, 2019 - April 24, 2020
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What Is “Fundamental”
October 28, 2017 to January 22, 2018
Sponsored by the Fetzer Franklin Fund and The Peter & Patricia Gruber Foundation

Wandering Towards a Goal
How can mindless mathematical laws give rise to aims and intention?
December 2, 2016 to March 3, 2017
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Trick or Truth: The Mysterious Connection Between Physics and Mathematics
Contest Partners: Nanotronics Imaging, The Peter and Patricia Gruber Foundation, and The John Templeton Foundation
Media Partner: Scientific American


How Should Humanity Steer the Future?
January 9, 2014 - August 31, 2014
Contest Partners: Jaan Tallinn, The Peter and Patricia Gruber Foundation, The John Templeton Foundation, and Scientific American

It From Bit or Bit From It
March 25 - June 28, 2013
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Questioning the Foundations
Which of Our Basic Physical Assumptions Are Wrong?
May 24 - August 31, 2012
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Is Reality Digital or Analog?
November 2010 - February 2011
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What's Ultimately Possible in Physics?
May - October 2009
Contest Partners: Astrid and Bruce McWilliams

The Nature of Time
August - December 2008

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white smith: on 7/12/17 at 10:16am UTC, wrote Now only I have seen the contest and think I am not late for applying my...

Eckard Blumschein: on 3/8/11 at 22:16pm UTC, wrote Dear David Layzer, You wrote: "the plausible – but, as I will argue,...

Dan Bruiger: on 2/28/11 at 23:10pm UTC, wrote Thanks, Anthony I will look at the papers you mention. On your point...

Steve Dufourny: on 2/24/11 at 12:04pm UTC, wrote Hello to all, Could you develop please this primordial cosmic medium ? ...

Anthony Aguirre: on 2/23/11 at 21:42pm UTC, wrote Dear Dan, As a collaborator of David Layzer's who has read a number of his...

Steve Dufourny: on 2/20/11 at 11:51am UTC, wrote Thank you very much,it is nice. You know you make me crazzy with your...

Dan Bruiger: on 2/20/11 at 1:03am UTC, wrote Dear David, You state that “…the strong cosmological principle holds...

Edwin Klingman: on 2/18/11 at 23:11pm UTC, wrote Steve, I will be happy to discuss your questions, which are very good...


H.H.J. Luediger: "Even darker.... one can not easily downrate a racehorse to a donkey, but..." in Undecidability,...

Steve Agnew: "Well thank-you, you are very kind. I have come to appreciate the fact that..." in Quantum Dream Time

Samuel Parsons: "O also means a whole new universe in a box can be recreated a miniverse..." in Outside the Box

Samuel Parsons: "Is it 127? It's always comes back here. Just saying also I'm trying to..." in Outside the Box

Zeeya Merali: "INSPYRE, INternational School on modern PhYsics and REsearch, organized by..." in Welcome to INSPYRE 2020 -...

David Sloan: "Dear Alan, For any discussion regarding the essay contest, the contact..." in Undecidability,...

Jonathan Dickau: "Thank you Peter... For the kind words of explanation. It is looking like..." in From Cosmic Lighthouses...

Lawrence Crowell: "Tejinder, I was intrigued by your FQXi essay. Thanks for this reference to..." in Alternative Models of...

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Building Agency in the Biology Lab
Physicists are using optogenetics techniques to make a rudimentary agent, from cellular components, which can convert measurements into actions using light.

Think Quantum to Build Better AI
Investigating how quantum memory storage could aid machine learning and how quantum interactions with the environment may have played a role in evolution.

Outside the Box
A proposed quantum set-up that could predict your game-playing strategy resurrects Newcomb’s classic quiz show paradox.

The Quantum Agent
Investigating how the quantum measurement process might be related to the emergence of intelligence, agency and free will.

First Things First: The Physics of Causality
Why do we remember the past and not the future? Untangling the connections between cause and effect, choice, and entropy.

May 28, 2020

CATEGORY: Is Reality Digital or Analog? Essay Contest (2010-2011) [back]
TOPIC: Do We Exist in Multiple Copies? by David Layzer [refresh]
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Author David Layzer wrote on Feb. 15, 2011 @ 16:56 GMT
Essay Abstract

ABSTRACT Garriga and Vilenkin have argued that under certain cosmological assumptions “the number of distinct histories in an [observable universe] is finite.” Consequently, each of us exists in infinitely many widely scattered copies. This essay explores some implications of an alternative cosmological hypothesis, which states that a full description of the universe doesn’t privilege any point or direction in space. The implications of this hypothesis include a proposed solution to the measurement problem of quantum mechanics and a new physical interpretation of Gibbs’s ensembles (collections of imaginary copies of a macroscopic physical system). An account of cosmic evolution that comports with the hypothesis makes randomness an objective property of the physical world and assigns a much wider role to chance than conventional pictures; but is not inconsistent with the possibility that we exist in multiple copies. At the end of the essay I speculate that creative biological processes, from evolution to cultural evolution to individual human lives, create qualitatively unique and unrepeatable varieties of biological order.

Author Bio

David Layzer is Donald H. Menzel Professor of Astrophysics emeritus at Harvard University. His publications include two books, Constructing the Universe (Scientific American Library) and Cosmogenesis (Oxford) and paper on theoretical physics, astrophysics, atmospheric physics, and theoretical biology.

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rww wrote on Feb. 15, 2011 @ 23:58 GMT
You say the qualitative aspects "slip the net of physics." You can't just mean they are subtle. That doesn't seem sufficient to rule out their duplication in an infinite universe. But you aren't suggesting, are you, a mind-body duality?

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egal wrote on Feb. 16, 2011 @ 03:03 GMT
Hi. Interesting essay although quite speculative. I wonder if it is not a bit off topic? May I ask how is this related to the contest foundational question? It may be somehow connected but it is hard to see it. Thanks.

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Steve Dufourny wrote on Feb. 16, 2011 @ 15:24 GMT
Hello dear David Layzer,

Nice to know you. Your essay was a pleasure to read. I am happy to see this rationalism and universalism. We need so much that. The confusions are at this momment so incredibles, I will say even ironic.

Thank you thus for that. The uniqueness is so essential and foundamental. You know, I beleive simply that they forget some foundamentals of evolution. Their maths methods seem lost in an ocean of confusions. They interpret without limits, domains....even the infinity is bad understood, that's why they interpret the newtionian fractalization of mass with infinity and others....I don't understand why they use these extrapolations, sometimes I say me simply that they confound the computing and the universal equation??? Bizare in all case,....

Your conlusions are very beautiful and general,frankly you merit to be a favorite.Good luck in this contest.

ps What do you think about Astrobiology,I am fascinated by that.You imagine the numbers of lifes inside this closed evolutive system in cooling and in distribution of codes.Sometimes I dream about these lifes on others planets, on these spheres turning around others spheres and turning still and always towards this aim if I can say.....The future of this Universal sphere is fantastic, imagine the numbers of interactions in this's a little as if we were catalyzers, conscious of this equation.And this equation evolves and optimizes itself by these intrinsic creations.The biology is fascinating and the word is weak.

This universe is incredible and still young.....the future and the present are fascinatings.I am persuaded even at this momment many many lifes live and even communicate and even invent and create also.....incredible and so rational.



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Edwin Eugene Klingman wrote on Feb. 18, 2011 @ 00:22 GMT
Dear David Layzer,

Thanks for a lucid, entertaining, and informative essay. I have a few comments and a general question.

Much seems to hinge on the assumption of an infinite universe. While I have much trouble imagining an infinite universe, I have just as much trouble imagining a finite universe, and neither seems subject to physical confirmation. The other assumption (G & V) is that the observable universe is in a definite quantum state. David Berlinski has pointed out that "physicists have found it remarkably easy to pass from speculation *about* the wave function of the universe to the conviction that there *is* a wave function of the universe."

But, based on those assumptions, I am happy to see that you arrive at the conclusion that you do, with respect to multiple copies of ourselves.

Now the question. An issue that has assumed some importance in this contest is the nature of information. Some insist that information is a physical "thing", while others, myself included, believe that information is descriptive in nature, dependent upon a frame or context, and having meaning only in a specific interpretation.

In this regard, you mention the information in biological structures, which is surely valid because DNA coding is interpreted by the cell. But then you speak of information "stored in sunlight", and in terms of non-random distributions in the Sun's core.

Let us assume that there are two theories of stellar processes, and that the energy (and possibly polarization) of the sunlight can be used to distinguish between these two and determine the 'correct' theory. Why is energy not sufficient for this process of interpretation? Why must one speak of 'information stored in sunlight'? What is it that physically exists besides the energy?

My point is that there seems to be a great deal of confusion as to whether or not information is physically 'real', as your usage suggests, and there seems to be no need in this case to speak of 'information stored'.

I realize that such usage is somewhat appropriate for probability distributions and entropy, but either it is descriptive, depending upon the context of an interpretative theory, or it is physical, having a reality above and beyond context.

Would you care to address this point?

Thanks again for a well written essay whose conclusion I agree with.

Edwin Eugene Klingman

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Steve Dufourny replied on Feb. 18, 2011 @ 11:01 GMT
Hi Edwin, I bother you sometimes but your words are relevant also.Thus sorry for my arrogance of baby sometimes.But I am nice , be sure and I like you and I like also read your posts.Sorry dear David layzer for your blog, I will be short.

I have thought about your c field, I think it's interesting and relevant, but I ask me if this field is only for biology?

I ask me also if the evolution and the newtonian encoding, were there are steps to find it,are the main piece of this field of consciousness???

In fact , do you see this field as a linearity as light and with different frequences for the polarity with mass.....or do you think it's possible to insert that in the blue gene or jaguar or the last ibm???

That implies some simple conclusions about the artificial intelligence and the number of spheres encoded....compared with a biological mass evolved also.....

At my humble opinion, there is a big big difference dear Edwin No,???

Now if the biology is inserted in the semi conductors, It's intriguing indeed,

Best Regards


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Edwin Eugene Klingman replied on Feb. 18, 2011 @ 23:11 GMT

I will be happy to discuss your questions, which are very good ones, but we should probably move to my thread rather than use Dr Layzer's.

I'll see you there.

Edwin Eugene Klingman

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Steve Dufourny replied on Feb. 20, 2011 @ 11:51 GMT
Thank you very much,it is nice. You know you make me crazzy with your works, it is relevant in fact.I am understanding better your researchs now.

Sorry Dear Dr Layzer, I am a little bad organized and a littel baby sometimes in my comportments, but as all things I evolve.

Best Regards


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Dan J. Bruiger wrote on Feb. 20, 2011 @ 01:03 GMT
Dear David,

You state that

“…the strong cosmological principle holds at all times if it holds at a single moment. I don’t see why this follows. Couldn’t there be changing (relatively local or temporary) isotropy and homogeneity?


“It follows that the present state of the cosmic medium, like earlier states, is fully characterized by a collection of probability distributions, including probability distributions of galactic and stellar masses. All these probability distributions are descended from and in principle deducible from the probability distributions that characterize the primordial cosmic medium”. Is it your intention to circumvent or eliminate the need for microscopic description (e.g. hidden variables?) Also, I don’t see that ‘descended from’ and ‘deducible from’ are necessarily the same. Comments?

I read your earlier book Cosmogenesis (1990). There is a reference in your paper to “(Layzer 2011)”, but I don’t see that on the reference page. Can you direct me to this?

Thanks and best wishes,


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FQXi Administrator Anthony Aguirre replied on Feb. 23, 2011 @ 21:42 GMT
Dear Dan,

As a collaborator of David Layzer's who has read a number of his more detailed papers, I could take a stab at your questions:

1) The issue here is that is the description at some time obeys the SCP, AND if the laws of physics do not privilege any direction or position, then the evolved description at a later time must also obey the CP.

2) I think the idea here -- which takes a while to get used to -- is that a complete characterization requires only statistical information, at the quantum OR classical level. I think this would be true even if there were quantum hidden variables: they too would be fully specified by their statistical properties. My reading is that 'descending' is what the physical world does, and 'deducing' is what we do using the known laws of physics.

A much more up-to-date (than cosmogenesis) and very nice exposition of these ideas can be found at, which I would recommend to anyone thinking about these issues. (I believe David is working on a revised version.) You could also check out the paper here that employs some of the same ideas from a slightly different perspective.

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Steve Dufourny replied on Feb. 24, 2011 @ 12:04 GMT
Hello to all,

Could you develop please this primordial cosmic medium ?

It's relevant all that.



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Dan J. Bruiger replied on Feb. 28, 2011 @ 23:10 GMT
Thanks, Anthony

I will look at the papers you mention.

On your point #2, I actually agree that all empirical knowledge is necessarily statistical. What you say about 'descending' and 'deducing' clarifies the distinction for me.


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Eckard Blumschein wrote on Mar. 8, 2011 @ 22:16 GMT
Dear David Layzer,

You wrote: "the plausible – but, as I will argue, incorrect – assumption that the domain of microphysics includes the domain of macrophysics".

Let me address something similar: Does the domain of real numbers really include the domain of rational numbers? I see this assumption also incorrect even if in this case we cannot reduce the flaw to probability.

Incidentally, I searched in your essay for reality, digital, continuous,discret, and past with no avail. I found the word analogous in a meaning that deviated from the topic "Is reality analog or digital?"

The word future led me to these sentences:"Our inability to predict the future is sometimes a consequence of our limited knowledge of the relevant laws and initial conditions. But not always. The outcome of a macroscopic process may be objectively indeterminate because a complete description of the initial conditions doesn’t contain enough fine-grained information."

This is not convincing to me. At first, I would never call a coarse description a complete one. Secondly I do not question causality. Thirdly, I consider closed systems in general more or less unreal idealizations.



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white smith wrote on Jul. 12, 2017 @ 10:16 GMT
Now only I have seen the contest and think I am not late for applying my essay. I have read the abstract and other details which you have shared here and got some clear idea about the matter.

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