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Anthony Aguirre: on 7/20/19 at 5:05am UTC, wrote Hi Stefan, Yes, I would say that the de Sitter region is locally...

Georgina Woodward: on 7/20/19 at 3:11am UTC, wrote The word 'energy' can refer to a measurable. That can be represented by a...

Lorraine Ford: on 7/20/19 at 0:29am UTC, wrote Georgina, We use symbolic representations when discussing aspects of the...

Georgina Woodward: on 7/19/19 at 0:36am UTC, wrote 'Energy' can be a measurable. Measured or calculated, number value assigned...

Lorraine Ford: on 7/18/19 at 22:34pm UTC, wrote Georgina, Energy is merely a category of information in the same sense...

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Lorraine Ford: on 7/18/19 at 2:23am UTC, wrote Honestly Georgina, Wake up! Change of number is NOT energy.

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FQXi BLOGS
November 17, 2019

CATEGORY: Blog [back]
TOPIC: Cosmological Koans [refresh]
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FQXi Administrator Anthony Aguirre wrote on Jul. 11, 2019 @ 17:02 GMT
A couple of months ago my book Cosmological Koans was released. Since I started this book before Max and I started FQXi in 2006, FQXI and the foundational questions community has obviously played a huge role in my thinking and what in the book. So I thought it would be nice to blog about it here and create some conversation. If you’ve not read it, I (surprise!) strongly recommend it. Limited spoilers to follow ;-)

I would say there are three overall aims of the book:

- Convey a lot of solid physics in a way that is (a) somewhat unusual in approach, (b) “real” in the sense of being conceptually solid such that with effort even someone with pretty limited background can get a real understanding of many core issues, (c) in a way that is tied to vivid stories rather than just text, so as perhaps to make things more immediate and memorable, and (d) in a way that highlights personal experience and at some level philosophical foundations rather than straight-up conventional physics concepts.

- Attempt to convey some of the sense of mystery, wonder, confusion and clarity that studying foundational physics contains. Despite a huge amount physics now describes very well, I wanted to get across in a visceral way that there are still deep and perplexing mysteries.

- Assemble something resembling a world-view that is rigorous in its physics, and in which observers play a key role, by highlighting how — to varying degrees — our description of the universe is a co-creation of the universe and the minds describing it.

Along the way, there are a number of science (and other) arguments to be made, including:

- My take on free will, which is that first one should clearly define what it would actually mean to have it (or not), then decide if that is a property of the relevant systems. I, for example, take free will to be the absence of a sense of coercion, an inability, even in principle, to perfectly predict one’s decisions/actions, decisions being made for reasons that the decider endorses, and the decisions being unknown without (the decider or another agent) going through the deciding process. I think humans have all of these properties (though that’s a long discussion, and not something I’d say I can prove.). Note that this definition does not require any sort of a-corporeal decision-making stuff outside the realm of physics (which there almost certainly is not), nor does it preclude there being influences on our decisions of which we are not consciously aware (which there almost certainly are.)

- Relatedly, my take on determinism. It drives my nuts when people say that the physics governing macroscopic systems (including humans) is deterministic. It’s just not. Schrödinger’s equation is deterministic, but it maps one current macroscopic configuration to many different future macroscopic configurations — like any other statistical theory (which may or may not be time-reversible). Whether you consider all of those distinct macro-outcomes to be equally real or only one to be real, the fact is that many of them exist in the evolved state. (And as for the argument that human brains are based on neurons that are essentially classical objects, that’s just not right thinking either — signaling is clearly affected by thermal noise, which is ultimately quantum in nature, so I think it’s very clear that one current brain state (or density matrix) corresponds to many distinct future ones, though we don’t know what the timescale for that divergence is.)

- My take on entropy and information. I and collaborators have spent a lot of time sorting out what I (now) think is the right way to think about Boltzmann vs. Gibbs entropy, in classical and quantum systems, in and out of equilibrium. Using the same word “entropy” for tho rather distinct concepts, as well as often using it interchangeably with “information” makes a lot of literature on the topic really confusing. But it need not be! I’ll write a separate blog about this but for those interested check out this paper, which spells things out fairly clearly (on the entropy side).

- An argument that sorting things into those that are “objective” and “not objective” is too simple and is misleading — it’s a sliding scale. There’s essentially nothing, I’d argue, that is totally objective. Even the mathematics we use is based on a set of axioms that we have selected out of many possibilities, and in which we have selected a tiny subset of all possible consequences of these axioms as “mathematics” (even though all are “true”). This selection corresponds to the creation of mathematical information. And admitting that things are not totally objective is OK — liberating even!

- An anti-reductionist thread pointing out that when we talk about one description being more “fundamental” than another (and don’t get me wrong, I’m a big fan of those descriptions!), it’s pretty hard to put a finger on exactly what we mean. And relatedly there’s almost always a whole lot of stuff (coarse-grainings, boundary conditions, assumptions about the state, indexical information, etc.) that must be added to a “fundamental” description, which undermine any idea that everything is in principle derivable just from the Hamiltonian. It’s just not.

And lots more! I had a great time writing and thinking it all through; for those who read it I hope you enjoy it and get provoked in various ways; and to everyone in the FQXi community thanks again for the support and inspiration!

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Stefan Weckbach wrote on Jul. 12, 2019 @ 03:59 GMT
Dear Anthony,

great to again receive a life-sign from fqxi and its founders.

The description of the contents of your book sounds extraordinarily exciting to me and I think I will get it from amazon soon.

I now have another “koan” for you and surely am not sure wether or not it is included in your book. But anyways I would like you to respond about the validity of my...

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FQXi Administrator Anthony Aguirre replied on Jul. 12, 2019 @ 22:44 GMT
Hi Stefan,

I've definitely thought about that Koan a lot (though it's not in the book), having written a couple of papers about past-eternal models that I think work, e.g.

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.6
7.083515

and one about models I think don't work:

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.
88.103504

The sneaky aspect of the ones that I think do work is that although along a given worldline into the past you get to a portion for which nothing happens — the worldline enters a timeless de Sitter phase — nonetheless because the space is infinite, as a whole you can say that the space is interesting, and things are happening, all the way back in time.

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Stefan Weckbach replied on Jul. 13, 2019 @ 08:09 GMT
Hi Anthony,

thanks for the link to your paper.

As i understood this paper, it is not just simply saying that the events it describes are ordered like on a circle, where every subject may conclude that it's universe is the temporal off-spring of some past event. Please correct me if I am wrong.

Your paper is indeed interesting and highly sophisticated. Good read though. And as I understood it, the timeless regions that are described therein give the needed ambiguity to have an infinite "reality as a whole" in both time directions.

But I would correct that, since we nonetheless are talking about causal events and mechanisms that would lead to the functioning of the cosmology you describe in your paper. I would correct that by saying that the more fundamental reason for universes to appear (including AOT's) is the existing of a timeless realm of reality. I think it would be confusing to nonetheless speak of something "all the way back in time".

For me, there is a difference between a timeless domain and a domain that somewhat contains both time directions simultaneously. But I think your paper made that clear by stating that there are two antipodal physical domains with respect to their AOT that shouldn't be causally connected at all. Therefore I think the timeless domain in your cosmology should be nonetheless be labeled as more fundamental as any notion of an AOT. A timeless domain simply has more degrees of freedom, concerning time, than a region with an AOT.

If your cosmology is correct, then everything comes out of that timeless domain. Interestingly that domain is characterized to be spatially infinite. But does this make some sense, since an imaginative observer couldn't even walk some two meters through it - because in this realm there isn't any time existent to do so in the first place.

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Stefan Weckbach replied on Jul. 13, 2019 @ 17:56 GMT
Hi Anthony,

i now have checked out your cosmology a bit more in detail.

I think your background space (de Sitter) isn't timeless as i assumed in my last post; at least in one of your talks about it you mention that it is statistically time-symmetric.

And I would have wondered if it were other, because as you also mentioned, different bubble-universes can collide with each other and additionally, it takes some time for the whole thing to be statistically time-symmmetric. So there is a before- and after globally, or am i wrong with this?

My lines of reasoning about this is that there must be a time where a collision hasn't occured yet and a time after such a collision has occured. Since such collisions are causal events that cause effects on both colliding universes, both universes, it seems to me, must share the same time-direction and the de Sitter background must also. Why? Because from the bird's view, before such a collision, both universes do not have any physical contact with each other and after that collision they had such a physical contact. So there is still the notion of before and after.

For now, i am forced to think that infinitely "all the way back in time" is not circumvented by your cosmology, even if the background is statistically time-symmetric. One could then well also talk about "all the way back from the future" instead of "all the way back into the past". But if the future itself is infinitely far away (has no end), we also cannot ever arrive at the moment where two universes collide and where we could know this happened (in the "future" or in the "past") according to some data in the microwave backround radiation.

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Robert H McEachern wrote on Jul. 12, 2019 @ 21:00 GMT
"our description of the universe is a co-creation of the universe and the minds describing it"

That has never been in doubt. The issue raised by all the absurd interpretations of quantum theory, is the claim that "our universe is a co-creation of our description of the universe and the minds describing it."

"It drives my nuts when people say that the physics governing macroscopic systems (including humans) is deterministic. It’s just not."

The universe is deterministic, in many respects. It is only the QM description of the universe that is not. The mere existence of random behaviors and "noise", is not sufficient to make deterministic behaviors impossible:

"signaling is clearly affected by thermal noise"

The entire point of modern communication theory, has been to totally eliminate that effect, along with the effects of common distortions and interference. Modern, high-speed communications are in fact possible, precisely because communications engineers, in the past few decades, have actually succeeded in that quest. Modern systems can now routinely send trillions of bits across networks, without a single error; something completely unimaginable only a few decades ago.

"My take on entropy and information... really confusing"

A gross understatement. Shannon's conception of Information, is fundamentally different from any concept in physics.

Rob McEachern

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FQXi Administrator Anthony Aguirre replied on Jul. 12, 2019 @ 22:52 GMT
Hi Rob,

> The universe is deterministic, in many respects. It is only the QM description of the universe that is not. The mere existence of random behaviors and "noise", is not sufficient to make deterministic behaviors impossible:

Indeed there are systems that are very well (if imperfectly) described by deterministic laws — indeed all classical systems — where the issue is then chaos and sensitivity to initial conditions. But the fact that a great many physics systems do have chaotic dynamics means that indeed the non-determinacy of QM does become important in just about everything, eventually. The quantitative question is how long it takes — ages for a planet's orbit, surely, but I suspect pretty quickly in a more complex system.

> The entire point of modern communication theory, has been to totally eliminate that effect, along with the effects of common distortions and interference. Modern, high-speed communications are in fact possible, precisely because communications engineers, in the past few decades, have actually succeeded in that quest. Modern systems can now routinely send trillions of bits across networks, without a single error; something completely unimaginable only a few decades ago.

That's a great point, and biological systems do similar things for example in the genetic code with error correction etc. But here we're talking about the brain, a decidedly non-digital architecture that many have argued is right at the boundary of a chaotic system. So I believe these random fluctuations will have a significant impact.

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Robert H McEachern replied on Jul. 13, 2019 @ 03:44 GMT
"the non-determinacy of QM does become important"

Only to the likes of us. My point is, the non-determinacy exists only in our description of reality, not reality itself. As you have noted, lack of knowledge of initial conditions will ultimately prevent you and I and even Laplace's "vast intelligence" from determining what happens in reality. But reality IS the initial condition, only...

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Lorraine Ford wrote on Jul. 13, 2019 @ 01:08 GMT
Re FQXi Administrator Anthony Aguirre wrote on Jul. 11, 2019 @ 17:02 GMT:

Physics is not “rigorous”.

Yes, physics has found fundamental-level static relationships which can be represented mathematically; and fundamental-level categories like mass, charge and position which can be represented as symbols in these mathematical representations; and matter, which physics claims is numb and dumb.

But physics says nothing about change: physics’ equations assume that change is somehow a property of the universe that needs no further questioning. (I.e. physics says nothing about what numbers are; and why these fundamental categories can be equated to numbers; and why any number should ever change; and why numbers “jump”.)

Physics cannot explain change; but even though it cannot explain change, physics has the arrogance to make pronouncements about “free will”. As is usual for physicists and philosophers when discussing “free will”, Aguirre veers off into totally irrelevant issues: “the absence of a sense of coercion”; “an inability … to perfectly predict one’s decisions/actions”; “a-corporeal decision-making stuff”.

Ho hum.

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Lorraine Ford replied on Jul. 14, 2019 @ 22:52 GMT
Physics has failed to explain change: physics tries to claim that change is just a fact of nature. Physicist Lee Smolin has even placed the following words on his website, with a background of ever-changing colours: “We live in a universe that is always changing, full of matter that is always moving” [1].

Change is hidden away (as a symbol representing an algorithmic procedure) in physics’ equations, so that physics can pretend that change is just a property of the universe. The lie of the idea that change is a property of the universe is given away by the fact that you need an algorithmic procedure to represent change.

1. http://leesmolin.com

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Steve Agnew replied on Jul. 17, 2019 @ 03:33 GMT
It is interesting that you bring up change in the context of free will...Just like matter is a part of physics, action is likewise a part of physics and science accepts both matter and action as otherwise unfounded beliefs or axioms, so it is not correct to say that physics fails to explain change. Change is simply the way things happen and there is no way to explain change. The smallest particle...

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Lorraine Ford replied on Jul. 17, 2019 @ 09:11 GMT
Steve,

As I said, the idea that change is a primitive aspect of the universe, “not developed or derived from anything else” [1], a property of the universe that can’t be de-constructed, is a lie. The change we are referring to would usually be number change or number jump; we are not referring to laws of nature changing, we are referring to numbers. Why can’t you even mention the word “number”?

1. https://www.lexico.com/en/definition/primitive (Oxford dictionary).

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Anonymous wrote on Jul. 13, 2019 @ 03:31 GMT
Dr. Aguirre,

Hi. Thank you for the new posting! I'm just an amateur who likes to think about these things, so forgive me if some of my comments are stupid, but here they are:

1. I'm not sure if I'm reading the below quote right

- Assemble something resembling a world-view that is rigorous in its physics, and in which observers play a key role, by highlighting how — to...

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Steve Agnew wrote on Jul. 14, 2019 @ 17:13 GMT
It is very pleasant to see a book on koans; both the fundamentally unanswerable questions as well as on simply unanswered questions that science might eventually answer. It is after all hard to know with certainty which koans are which.

It is revealing that koans embrace the notions of infinitely divisible time and space, which results in endless Zeno rabbit holes. There also does not seem to be a koan for the nature of quantum phase, which results in endless and very deep relativistic rabbit holes. Discrete causal sets with quantum phase and mass energy equivalence seem to be one way out of the ubiquitous rabbit holes of Zeno relativity, but these koans seem to take the reader even deeper...

Philosophy specifically asks both kinds of questions and then argues about the answers endlessly. Science can really only address questions that it can answer, but science is never quite sure about its own limits.

The Zen Buddhist koan is an interesting metaphor for both unanswerable as well as just currently unanswered questions. The vehemence of koans shows how mainstream science often vigorously disagrees with itself, but vigorous disagreement is what differentiates philosophy from science.

The objectivity of science contrasts with the subjectivity of philosophy since objective measurement determines science while subjective reasoning determines philosophy.

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Steve Agnew replied on Jul. 14, 2019 @ 17:50 GMT
Understanding physical reality means avoiding two very deep rabbit holes...

First rabbit hole is the notion of infinitely divisible time and space, Zeno’s paradox.

In fact, both time and space emerge from discrete causal sets.

Second rabbit hole is the notion of relativity without any quantum phase, Schrödinger’s paradox.

Quantum phase plays no role in gravity relativity, but quantum gravity with mass energy equivalence emerges from discrete causal sets with quantum phase...

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Lorraine Ford wrote on Jul. 17, 2019 @ 21:50 GMT
The arrogance of physics and philosophy, when it comes to the subject of free will, is on display in physicist Anthony Aguirre’s above piece.

Why does Aguirre use terms like “the absence of a sense of coercion”, “an inability … to perfectly predict one’s decisions/actions”, and “a-corporeal decision-making stuff” ??

Answer: because he believes that “free will” is all about the vagaries of a high-level description of reality. Aguirre doesn’t believe that free will could be causing any GENUINE change at the level of the building blocks of reality.

Genuine free will [1] is about the power to genuinely change the numbers that apply to fundamental categories like position and energy. Genuine free will implies that human beings and living things are genuine participants in the world.

1. Free will: “The power of acting without the constraint of necessity or fate”, https://www.lexico.com/en/definition/free_will (Oxford dictionary)

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