*Singular Universe* (Nov 2014) by Smolin and Unger

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*Singular Universe* (Nov 2014) by Smolin and Unger

Postby Marshall on October 17th, 2014, 6:02 pm 

http://www.amazon.com/The-Singular-Univ ... 1107074061

The full title is *The Singular Universe and the Reality of Time: A Proposal in Natural Philosophy*

The publisher is Cambridge University Press and it's scheduled to come out 30 November.

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby TheVat on October 17th, 2014, 6:42 pm 

Wow, two outstanding thinkers come together, this sounds like a must-read. Unger is the guy who was a key player in democratizing Brazil, and his social theory, "false necessity, " is wondrous and brilliant. I would read a book where Smolin and Unger talked about how to shampoo a dog.
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Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Marshall on October 17th, 2014, 7:41 pm 

That's a strong recommendation! (about the dog).
From a comment by Smolin last year, i don't remember where I saw it, I suspect the first half (or 2/3) of the book is primarily by Robert Unger, and the the second part is the more PHYSICKY and primarily by Smolin. I guess they didn't fuse their viewpoints--but stimulated and encouraged and inspired each other. Smolin said it's very exciting to work with Unger a lot of ideas (often bold, original, an uncommonly insightful guy).

My guess is that Unger's part is more theory of theories. The general nature of physical law, how it evolves, how we think the world. I think Smolin's part will be about some of the same themes as in Time Reborn but more specifically focused on a particular proposal for how LAWS THEMSELVES EMERGE FROM disorder AND EVOLVE. How physics can be "self-organizing", how regularities (like those governing particles of matter, or like the relation between geometry and matter expressed in the GR equation) can actually DEVELOP over time.

I think perhaps somewhat like the development of law in human societies, by accumulation of precedents and the growth of custom and tradition. Or like biological evolution? Or some combination??
He has a very simple "meta-law" according to which the more complicated known physical laws can, he thinks, have arisen. As if Nature gets into ruts.

Smolin and Cortes have run TOY model simulations of this process, if I remember correctly.

But that's just a guess. The most recent Smolin Cortes paper was about something I found more immediately intriguing, not so nebulous. An improvement of Causal Sets that both overcame some problems and made it possible to link the theory to a new variant of LQG developed by Wolfgang Wieland. Maybe that will be worked into Smolin's part of *Singular Universe* too. I don't at all see how it could be, but it might.

Singular Universe -- Unger & Smolin -- discussed anywhere?

Postby Matthew on January 26th, 2015, 3:14 pm 

Hello group. I am currently reading (in Unger's last chapter) "Singular Universe" authored as 2 separate works by Lee Smolin and Roberto Unger. I'm starting here in "Cosmology" because this is the central theme of the book, but it is also very much intended as "Natural Philosophy". So for now, I am just wondering if this book is being discussed anywhere else on this forum. If so, I will take up my readings there. If not, perhaps a moderator can suggest where such a discussion would best begin.

Matthew Rapaport

Re: Singular Universe -- Unger & Smolin -- discussed anywher

Postby Marshall on January 26th, 2015, 6:39 pm 

This is a good place to locate your thoughts about Unger and Smolin's ideas.
this book has been very slow coming and some of the ideas have indeed been discussed in earlier threads but they would be long-gone---several years old---and more trouble to connect with than it would be worth.

Some of us have read Smolin's earlier book *Time Reborn* which I suspect goes over some of the same ground as his part of *Singular Universe*. I own *TR* but probably will not buy *SU*. I've browsed it, though, and may eventually dig in a little deeper.

Personally I'd be delighted if you would be willing to summarize Smolin's arguments and sketch what he is proposing. To break the ice I will attempt a summary IMPROMPTU which will necessarily be incomplete and most likely wrong in places. Then, if you like, you can correct me on this or that, or give your own more complete account.

I encourage you not to take what I say too seriously and tell the story your own way, as much as you have time and energy to tell. What I say is based on earlier video lectures&scientific papers by Smolin, and on *TR*, so it may not exactly match what you find in *SU*.

Re: Singular Universe -- Unger & Smolin -- discussed anywher

Postby Marshall on January 26th, 2015, 7:01 pm 

1. the fact that we're trying to model the whole universe is important because the Newtonian paradigm (isolated subsystem, seen from outside, initial conditions, evolving according to laws) only applies to subsystems.
We are part of the universe, so there are no separate observers.

2. It's also important because when it is the whole universe you are studying there is no distinction between initial conditions and laws. We need a different approach from that embodied in the Newtonian paradigm.

3. Principles: sufficient reason and reciprocal action. If the universe is this way rather than that way there should be a reason for it. Nothing acts on anything without itself being affected--any actor is itself acted upon.

4. Because of these principles there can be no eternal unchanging LAWS. (they would be acting on our reality without in turn being themselves acted upon. There is nothing outside nature, not even Laws.

5. There should be a sufficient reason why we see THESE laws rather those OTHER possible laws.

6. Therefore the laws must have EVOLVED, and be evolving, even as they regulate other natural processes.
Perhaps they evolve in a way similar to HUMAN laws, by the accumulation of precedents.

7. Maybe the outcome of any given interaction is determined according to a kind of "meta-law" by polling the precedents---events that occurred in similar situations. Or maybe not. This is still conjectural and a work in progress. Smolin is still exploring mechanisms by which physical laws may have evolved.

8. However one thing (according to him) is clear. If the regularities in Nature evolved, then they must have evolved OVER TIME. Therefore "time" must be real and fundamental.

Re: Singular Universe -- Unger & Smolin -- discussed anywher

Postby Marshall on January 26th, 2015, 7:16 pm 

An interesting side problem is the problem of NOW. what is special about our experience of the present?
shouldn't our model of the universe be able to represent the qualities of experience, like the difference between the past and the present? the prevailing model is General Relativity (GR) and it does not have a way to represent the present moment. It favors a "block universe".

Smolin has some interesting papers with Marina Cortes. they are working on something they call Energetic Causal Sets (ECS).

they have a very interesting (but technical in places) paper they wrote in July 2014.

I think you can get it if you google "cortes smolin energetic causal spin foam" or some subset of those words.

That work is probably too recent to have been included in the Singular Universe book. Books take a long time to edit publish and bring to market.

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Matthew on January 27th, 2015, 1:50 pm 

So this book has indeed come out and it is indeed a good read. I am currently in the last chapter of Unger's part. His style is interesting. He cycles round and round the subject somewhat redundantly, but at each cycle adding a little more flesh to the bones. What emerges at the end is a well constructed proposal covering all the bases he wants to cover. Will avoid commenting on the content until I've actually read it all, but so far I find Unger's proposal in "natural philosophy" very plausible and, if I might "common sensical". For example he asserts that despite the well understood LOCAL effects of GR, there is indeed a "preferred reference frame" and "global time" in the universe. It is this that allows us to say (for example) that the present universe is 13.8 billion years old.

As for the reference frame, though Unger only alludes to a "position where all the galaxies are receding from one another", in fact this idea was given more specific content by Andrew Thomas in his "Hidden in Plain Sight" (I forget if in II or III). Thomas points out that the big bang is what imparted all initial motion (an inertial frame) in the universe. The momentum of this inertial frame nets out to zero because it happens equally in all directions but it remains true that everything that moves in the universe (that being everything) relative to anything else moves also relative to this universal frame. As a result, we have a hypothetical preferred frame of reference, and a universal clock because all motion can be measured against the universal frame.

So Thomas' insight well reinforces Unger's and again (in my opinion anyway) leaves Unger eminently sensible.

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Marshall on January 27th, 2015, 6:35 pm 

Hi Matthew, I wouldn't make too much of the existence of a criterion of rest in Cosmology. It is not an issue. It has been around at least since the 1940s. One used to say "at rest with respect to the Hubble flow". I.e. a standpoint from which the percentage distance growth rate looks symmetrical .

And then around 1960 or so the CMB was observed. The ancient light that emanated from the ancient matter circa year 280,000 when the universe cooled enough to become transparent. And then one had an improved criterion of rest (no doppler hot-spot) same temp in all directions. And one said "at rest with respect to Cosmic Microwave
Background" or "at CMB rest".

Observations from a moving platform like the solar system or the earth are often corrected so that they are from a CMB stationary position. the cosmologist's UNIVERSE time , or "FRIEDMANN TIME" is that measured by an imagined family of observers all over the universe all of whom are AT CMB REST and so can in principle synchronize clocks.

It all depends on there being the ancient matter which was originally uniformly spread out before it started clumping and falling towards other clumps and developing individual random motions.

Pure GR, without an ancient matter criterion of rest, does not have a preferred time, or preferred local frames.

Still, it does have commonsensical appeal! It is very appealing (at least to me and probably a good many other people) to take the longstanding "universe standard time" of Cosmology to be a kind of fundamental time, and put it on a pedestal so to speak.

To me this does not seem to depend very much on whether or not Unger advocates doing that.

But it is good that both Thomas and Unger TALK about the CMB, and the universal rest criterion, and the universe standard time---these are important parts of conventional Cosmology. You need them to formulate Hubble Law expansion and to define the conventional standard cosmic model. So it is good stuff to be learning (whether or not there is some ultimate philosophical meaning.)

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Marshall on January 27th, 2015, 7:32 pm 

Don't mean to minimize the importance of Smolin Unger book. For me the great importance is not that it points to a particular candidate for Standard Time (that developed by Cosmologists ever since Hubble reported expansion around 1940)

For me the great importance is in promoting the idea that at least some natural laws have EVOLVED
(rather than being "God-given" or basically unexplainable, just a lucky for us we accidentally got nice ones).
It is great that they not only propose evolution (and therefore don't give up on the physicist job of explaining everything including why these laws) but that they also offer one or more possible EVOLUTIONARY MECHANISMS.

This is where Smolin's work with MARINA CORTES comes in.

I like very much the Smolin Unger book because it is basically death to the Multiverse

where by Multiverse I mean giving up the quest to explain why things are this way rather than that other way, giving up on explaining why we have these physics laws rather than some other.

I think their title is advertising their rejection of that kind of Multi-cowardice or Multi-defeatism. Because they say SINGULAR universe, in their title. they reject Multi-resignation.

I don't at all mind the model universe having different regions as long as the model-builder is not abdicating, shirking, renouncing physicist responsibility and taking easy way out of saying it's all a big accident.

So I cheer them on, and Marina Cortes too. But the business about reminding readers about Universe Standard Time and its role in Cosmology is not the big thing, it is just serving to soften the readers upso they will be more able to accept the more radical idea that laws evolve.

Smolin seems to think you can't have laws evolve if you don't have TIME, because for him evolution means things evolving over time. Im not sure about this, there may be some kind of atemporal evolution
or asynchronous becoming. Like the way a coral reef grows independently at every point, without a master clock setting the pace.

But Smolin thinks you have to have Time in order to have Laws evolve, patterns of regularity appear, so OK. He thinks that, and his readers probably think that, so he has to soften them up by making them accept the idea of a master clock. "Look! cosmologists already have one! It's basic to the field!" and then they will be more receptive to the idea of emergent patterns of regularity.

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Matthew on January 27th, 2015, 10:05 pm 

I didn't mean to imply that Unger's notion of a preferred frame of rest was in any way a center piece of the work. Indeed it is merely a correlate of his assertion that time is real and fundamental. Still I've read a lot of cosmology and philosophy of science over the last few years and it certainly seems as though the majority of cosmologists these days deny that this is so and they base this denial on what Unger calls the metaphysical gloss laid onto SGR.

Julian Barbour (End of Time) is, for his own reasons one of the chief deniers of the reality of time in general (if I recall Unger mentions him) but his idea of a "hyperplain" none the less demands that there is some "now" corresponding to my "now" (even if we cannot physically map it) everywhere in the universe!Process, causation, only happens in the present, and there has to be something happening, now, everywhere in the universe

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Marshall on January 28th, 2015, 2:43 am 

Matthew » Tue Jan 27, 2015 7:05 pm wrote: Still I've read a lot of cosmology and philosophy of science over the last few years and it certainly seems as though the majority of cosmologists these days deny that this is so...

Real and fundamental are kind of vague words, that's a different topic of conversation. What I'm talking about is what cosmologists do now, every day. they have a universe standard time, which they use constantly. the standard model (LambdaCDM) runs on it.
You cannot define the Hubble Law of expansion without it. It is the time variable in the basic Friedmann equation.
the Hubble Law deals with the INSTANTANEOUS PERCENTAGE GROWTH RATE universe-wide.

the percentage growth rate H(t) at a given moment of universe time all over the universe.

that said, in GR there is no time I would call real or fundamental. Time is observer dependent. You only get something you can properly call time AFTER you have a particular solution to the equation and you have a block universe and you can track a given observer and say what his clock reads. Cosmologists use a CLASS of observers, those at rest with respect to certain matter and radiation. But it is still contingent. It depends on a given initial condition and a particular solution.

Re: *Singular Universe* (Nov 2014) by Smolin and Unger

Postby Matthew on February 7th, 2015, 9:10 pm 

I posted a longish review of this on amazon. Would be nice to get into more technicalities here but there doesn't seem to be much discussion going! Both authors argue for very much the same conclusions about cosmology, physics, and mathematics using quite different approaches! Smolin reprises his argument from "Time Reborn" but I think this version is more concise, focused, and easier to follow.

I like the way Unger writes but he happens to be wrong about ontology trying to fix "kinds". E. J. Lowe's "Four Category Ontology" for example is compatible with a "history over ontological structure" view and requires only that we be in a phase where kinds of some kind exist.

But that is but a quibble! This book has lots of potential for discussion

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