Today’s Bloggingheads dialogue features me and writer John Horgan — I will spare you a screen capture of our faces, but here is a good old-fashioned link.
John is the author of The End of Science, in which he argues that much of modern physics has entered an era of “ironic science,” where speculation about unobservable things (inflation, other universes, extra dimensions) has replaced the hard-nosed empiricism of an earlier era. Most of our discussion went over that same territory, focusing primarily on inflation but touching on other examples as well.
You can judge for yourself whether I was persuasive or not, but the case I tried to make was that attitudes along the lines of “that stuff you’re talking about can never be observed, so you’re not doing science, it’s just theology” are woefully simplistic, and simply don’t reflect the way that science works in the real world. Other branches of the wavefunction, or the state of the universe before the Big Bang, may by themselves be unobservable, but they are part of a larger picture that remains tied to what we see around us. (Inflation is a particularly inappropriate example to pick on; while it has by no means been established, and it is undeniably difficult to distinguish definitively between models, it keeps making predictions that are tested and come out correct — spatial flatness of the universe, density fluctuations larger than the Hubble radius, correlations between perturbations in matter and radiation, fluctuation amplitudes on different scales that are almost equal but not quite…)
If you are firmly convinced that talking about the multiverse and other unobservable things is deeply unscientific and a leading indicator of the Decline of the West, nothing I say will change your mind. In particular, you may judge that the question which inflation tries to answer — “Why was the early universe like that?” — is a priori unscientific, and we should just accept the universe as it is. That’s an intellectually consistent position that you are welcome to take. The good news is that the overwhelming majority of interesting science being done today remains closely connected to tangible phenomena just as it (usually!) has been through the history of modern science. But if you instead ask in good faith why sensible people would be led to hypothesize all of this unobservable superstructure, there are perfectly good answers to be had.
The most important point is that the underlying goal of science is not simply making predictions — it’s developing an understanding of the mechanisms underlying the operation of the natural world. This point is made very eloquently by David Deutsch in his book The Fabric of Reality. As I mention in the dialogue, Deutsch chooses this quote by Steven Weinberg as an exemplar of hard-boiled instrumentalism:
The important thing is to be able to make predictions about images on the astronomers’ photographic plates, frequencies of spectral lines, and so on, and it simply doesn’t matter whether we ascribe these predictions to the physical effects of gravitational fields on the motion of planets and photons or to a curvature of space and time.
That’s crazy, of course — the dynamics through which we derive those predictions matters enormously. (I suspect that Weinberg was trying to emphasize that there may be formulations of the same underlying theory that look different but are actually equivalent; then the distinction truly wouldn’t matter, but saying “the important thing is to make predictions” is going a bit too far.) Deutsch asks us to imagine an “oracle,” a black box which will correctly answer any well-posed empirical question we ask of it. So in principle the oracle can help us make any prediction we like — would that count as the ultimate end-all scientific theory? Of course not, as it would provide no understanding whatsoever. As Deutsch notes, it would be able to predict that a certain rocket-ship design would blow up on take-off, but offer no clue as to how we could fix it. The oracle would serve as a replacement for experiments, but not for theories. No scientist, armed with an infinite array of answers to specific questions but zero understanding of how they were obtained, would declare their work completed.
If making predictions were all that mattered, we would have stopped doing particle physics some time around the early 1980’s. The problem with the Standard Model of particle physics, remember, is that (until we learned more about neutrino physics and dark matter) it kept making predictions that fit all of our experiments! We’ve been working very hard, and spending a lot of money, just to do experiments for which the Standard Model would be unable to make an accurate prediction. And we do so because we’re not satisfied with predicting the outcome of experiments; we want to understand the underlying mechanism, and the Standard Model (especially the breaking of electroweak symmetry) falls short on that score.
The next thing to understand is that all of these crazy speculations about multiverses and extra dimensions originate in the attempt to understand phenomena that we observe right here in the nearby world. Gravity and quantum mechanics both exist — very few people doubt that. And therefore, we want a theory that can encompass both of them. By a very explicit chain of reasoning — trying to understand perturbation theory, getting anomalies to cancel, etc. — we are led to superstrings in ten dimensions. And then we try to bring that theory back into contact with the observed world around us, compactifying those extra dimensions and trying to match onto particle physics and cosmology. The program may or may not work — it’s certainly hard, and we may ultimately decide that it’s just too hard, or find an idea that works just as well without all the extra-dimensional superstructure. Theories of what happened before the Big Bang are the same way; we’re not tossing out scenarios because we think it’s amusing, but because we are trying to understand features of the world we actually do observe, and that attempt drives us to these hypotheses.
Ultimately, of course, we do need to make contact with observation and experiment. But the final point to emphasize is that not every prediction of every theory needs to be testable; what needs to be testable is the framework as a whole. If we do manage to construct a theory that makes a set of specific and unambiguous testable predictions, and those predictions are tested and the theory comes through with flying colors, and that theory also predicts unambiguously that inflation happened or there are multiple universes or extra dimensions, I will be very happy to believe in the reality of those ideas. That happy situation does not seem to be around the corner — right now the data are offering us a few clues, on the basis of which invent new hypotheses, and we have a long way to go before some of those hypotheses grow into frameworks which can be tested against data. If anyone is skeptical that this is likely to happen, that is certainly their prerogative, and they should feel fortunate that the overwhelming majority of contemporary science is not forced to work that way. Others, meanwhile, will remain interested in questions that do seem to call for this kind of bold speculation, and are willing to push the program forward for a while to see what happens. Keeping in mind, of course, that when Boltzmann was grounding the laws of thermodynamics using kinetic theory, most physicists scoffed at the notion of these “atoms” and rolled their eyes at the invocation of unobservable entities to explain everyday phenomena.
There is also a less rosy possibility, which may very well come to pass: that we develop more than one theory that fits all of the experimental data we know how to collect, such that they differ in specific predictions that are beyond our technological reach. That would, indeed, be too bad. But at the moment, we seem to be in little danger of this embarrassment of theoretical riches. We don’t even have one theory that reconciles gravity and quantum mechanics while matching cleanly onto our low-energy world, or a comprehensive model of the early universe that explains our initial conditions. If we actually do develop more than one, science will be faced with an interesting kind of existential dilemma that doesn’t have a lot of precedent in history. (Can anyone think of an example?) But I’m not losing sleep over this possibility; and in the meantime, I’ll keep trying to develop at least one such idea.
I am an example of the person Sean discusses in his conversation with Horgan – a layperson who finds cosmology fascinating, and who will listen to experts in the field with rapt interest. For what it’s worth, I do not believe in god, and I certainly don’t think cosmology is theology. I appreciated this conversation, however, since I have friends who have had discussions like this one, and it was wonderful to listen to someone as brilliant as Sean break down certain arguments at length. Thanks for the wonderful, provocative post.
I think John Horgan can’t read
from wikipedia article on science
“Mathematics, which is sometimes classified within a third group of science called formal science, has both similarities and differences with the natural and social sciences. It is similar to empirical sciences in that it involves an objective, careful and systematic study of an area of knowledge; it is different because of its method of verifying its knowledge, using a priori rather than empirical methods. Formal science, which also includes statistics and logic, is vital to the empirical sciences. Major advances in formal science have often led to major advances in the physical and biological sciences. The formal sciences are essential in the formation of hypotheses, theories, and laws, both in discovering and describing how things work (natural sciences) and how people think and act (social sciences).”
He should really study Dirac
I was interested in Sean’s view, expressed in the Talking Heads discussion, that the evidence for Inflation isn’t as solid as is often assumed.
Since he’s not known to be a crackpot, it might be useful to list the main reasons for this mild scepticism.
Maybe in a separate thread?
CT, it’s not that “evidence for inflation” isn’t as solid as is often assumed, it’s that (in my opinion) the underlying theoretical justification isn’t as solid as many people like to think. Roughly, inflation solves the fine-tuning of the early universe by assuming that it was even more finely-tuned. I’ll write more about it if I get the chance.
Isn’t fine tuning impossible to avoid given the fact that entropy was much lower in the past and any explanation for low entropy initial conditions in terms of fluctuations in an earlier more typical high entropy state leads to the Boltzmann Brain paradox?
Sean: “… all of these crazy speculations about the multiverses and extra dimensions originate in the attempt to understand phenomena that we observe right here in the nearby world.”
Alright, I’m going to say it…
Modern physics evolved from the 4 dimensions that were defined by our experience. None of the additional dimensions that have hitherto been postulated by mainstream physicists in an attempt to explain certain observations have reflected anything that we experience.
If we are going to start adding dimensions, doesn’t it make sense that they be dimensions in the same sense as the first four – dimensions that reflect experience? And if we are going to try to use those dimensions to solve physics problems, doesn’t it make sense that we first have to understand what it’s like to experience that dimension?
I’m just saying…
From wikipedia entry on the 5th dimension – “It has occasionally been stated the Fifth dimension is probability, meaning that the fifth dimension is the full amount of possibilities that could happen or, in other words, alternate realities.”
How about it, Sean? What about the idea of another dimension that can actually be experienced?
Have you ever experienced an atom?
Have you ever experienced noncommutativity of observations?
How about spacetime curvature?
Vacuum polarization?
Quark confinement?
Modern physics is almost entirely about stuff that is not part of your experience.
Quantum mechanics, relativity, quantum field theory, … are all subjects which are tremendously counterintuitive, precisely because they deal with phenomena far removed from our ordinary experience (and hence our intuition, built on that experience, fails miserably when applied to them).
Expecting Modern Physics to reflect things that we experience is to entirely miss the point.
Sean on Mar 17th, 2008 at 2:39 pm
CT, it’s not that “evidence for inflation” isn’t as solid as is often assumed, it’s that (in my opinion) the underlying theoretical justification isn’t as solid as many people like to think. Roughly, inflation solves the fine-tuning of the early universe by assuming that it was even more finely-tuned. I’ll write more about it if I get the chance.
——————
I’d tend to second this. The exact model is unknown, but the basic scheme is approximately correct. The inflation of the early cosmos by a Higgsian inflaton that shoved the universe from a false vacuum to a real vacuum appears to fit within astronomical data. What we don’t know is what model this works within, what this has to do with quantum gravity and so forth. It is like Darwin, he got the evolutionary scheme more or less on the mark, but lacked the biological underpinning of it called the genetic code.
Lawrence B. Crowell
Random Speculation: Since the mechanism(s) for inflation and dark energy are both unknown but both cause what appears to be an expansion in the cosmos, is there a possibility that they are phenomenologically related or is this ruled out by the data?
e.
Quantum mechanics, relativity, quantum field theory, … are all subjects which are tremendously counterintuitive
but necessary to explain experiments. Contrast this to supersymmetry, which get increasingly disfavored by experiments as time goes by.
Interestingly enough, Paul Steinhardt seems to think that inflation is incompatible with string theory. Since Steinhardt is a world-class scientist, maybe one should pay attention.
“Since Steinhardt is a world-class scientist, maybe one should pay attention”
Note: The following comment isn’t intended to pick on Dr Steinhardt.
Their is an elitist fallacy that seems to continuously permeate academia as well as physics that if you don’t have a Ph.D. or tenure (or a bunch of papers that have been cited in other work); that you are an imbecilic cretan.
There are a lot of smart people that have full comprehension of the issues involved in physics (and other fields of science) but for various reasons have either chosen not to pursue a Ph.D. in physics, or were not allowed to by circumstance.
Now, my previous comment aimed at Mr Horgan hopefully was taken in jest (if not, then now you know to take it in jest); and although I disagree with the man, he obviously is intelligent enough to participate in a legitimate way and highlights a significant point.
The point is that most people, including many naive “scientists”, are not what they think they are. Karl Popper is perhaps the person who has best described the current popular philosophical approach as “critical rationalism”; and is the point of view of supported by John Horgan’s arguments.
http://en.wikipedia.org/wiki/Karl_Popper
http://en.wikipedia.org/wiki/Critical_rationalism
Sean, on the other hand, is promoting “logical positivism”; which was the philosophy advocated by the Vienna Circle, and is the dominant view enshrined in theoretical physics (and string theory).
http://en.wikipedia.org/wiki/Logical_positivism
http://en.wikipedia.org/wiki/Vienna_Circle
Personally, if forced to choose, I would consider myself a “logical positivist”; however, I don’t think I am required to adhere to any one philosophy at any one time, and I will choose whichever is convenient to support whatever particular argument I choose to make.
#57 – I think you missed my use of the words ‘evolved from’. No one disputes what modern physics is now.
“Expecting Modern Physics to reflect things that we experience is to entirely miss the point.”
Except that it’s not. Too many aspects of human experience are unsatisfactorily explained by modern physics. If anything, human experiences points to things that call the current interpretations of modern physics into question. (Don’t get me wrong; right now, I’m really picking at only two points – the idea that the collapse of the wave function reflects something permanent and irreversible, and the idea that state selection is random. I think that there is a range of human experiences that shows us that it’s not.)
One more thing before I duck and run for cover… I think this is, at least somewhat, Horgan’s point – modern physics, for the most part, is not adding to our understanding of our experiences. If we cannot add to that, then perhaps science really is ending.
Elliot on Mar 18th, 2008 at 12:25 am
Random Speculation: Since the mechanism(s) for inflation and dark energy are both unknown but both cause what appears to be an expansion in the cosmos, is there a possibility that they are phenomenologically related or is this ruled out by the data?
e.
The early inflation of the universe and the current “eternal inflation” of the slow acceleration of the universe are obviously related in some way. They are likely due to a dilaton, say in conformal gravity SU(2,2) (or SU(4) ), which both contain the deSitter SO(4,1) and Anti-deSitter SO(3,2) groups. The deSitter cosmology has an event horizon at
$latex
r~=~sqrt{Lambda/3}
$
for the cosmological constant Lambda about 10^{-54}cm^{-2}. This is inducing the acceleration in a way analogous to a black hole horizon. The very early universe had this cosmological constant vary according to some scalar field so that
$latex
Lambda~=~Lambda(phi,~{dotphi})
$
and this scalar field is probably somehow related to the dilaton field of the current eternal inflation. In fact the inflationary universe was deSitter-like in all probability. So there must be some set of scalar, Higgian fields that act as dilatons and inflatons.
Lawrence B. Crowell
I can’t think of any human experiences that involve quantum superposition. So I’m not sure we can trust any intuition from our experience about the proper interpretation of such phenomena.
(The whole reason why “Schrœdinger’s cat” sounds so paradoxical is that quantum superposition is totally alien to our, and our feline friends’, experience.)
That’s a logically defensible position. I just think it’s wrong. The purpose of science is to understand how the natural world works, not just that small bit of it that is directly the subject of our experience.
Lawrence,
Thank you for taking the time to characterize this is more a more precise scientific description.
e.
Lawrence B Crowell wrote (#40) :
>
> I don’t particularly buy this idea there is some plethora
> of cosmologies. First off I think this is too easy a way out.
Yes, it seems to go against Occam’s Razor. But it is more in keeping with an infinitely recursive structure, and many find this “no first causes” idea more satisfying than a single large cosmos popping out of essentially nothing purely by chance.
It’s fairly clear in general terms how dark energy might drive a cyclic cosmic evolution, in conjunction with the mysterious opposing force discussed on this very forum only a week or two ago (the “sideways vector field” Sean described).
I’ll summarize this briefly below, *and* suggest how the fine tuning required for it to work could constrain constants in existing models and thus make it accessible to experiment.
First a crude analogy of waves breaking on a flat beach. Please don’t take it too literally, or fear I may! We all know how this works – The wave rears up and over in shallow water, is accelerated downward by gravity and after breaking continues up the beach getting flatter and slower until it stops and then draws back. Note that this undertow, which helps shape the next wave, is in a sense tangential or “dual” to it. Note also that in racing up a stony beach and then receding, a wave “grades” the pebbles, in decreasing size toward the shore.
In the distant future, most mass-energy will end up in black holes, and those surviving will over vast times have evaporated until their temperatures are comparable to the ambient temperature and are therefore equal in mass.
The model I sketch requires that the expansion eventually slows to a stop and goes into reverse, and the fine tuning referred to above demands that some black holes survive intact until this stage (see below).
Once the universe starts contracting, the background temperature rises and the continued survival of black holes is thus assured. Also, to reset the entropy clock for the next cycle, the black holes reduce their collective degrees of freedom by joining in symmetrical open and closed chains, which I identify with strings.
(The work of Douglas, http://arxiv.org/abs/hep-th/9608024 if I haven’t misunderstood it, suggests that branes comprise compacted strings. That being so, why can’t a string be a chain of branes, identifying the black holes’ event horizon as a brane? Believing in an infinite heirarchy of structure, I don’t buy the notion of strings being fundamental objects! For example, in some respects a crystal fracture boundary behaves like a string; but that isn’t fundamental is it?)
Anyway, if anyone is interested, I have a paper proposing exactly how black holes could form and maintain these symmetric assemblies, without either combining or falling apart. I propose this works by a combination of frame dragging, and the holes ejecting via polar jets a portion of the energy made available by the shrinking universe. Of course the energies involved are miniscule, but this works over vast timescales.
During the contracting stage, the next Big Bang takes shape by duality which by some means combines AdS/CFT, Scale Factor, and Time-Temperature dualities. Assuming this is akin to a Fourier transform between suitable domains, an uncertainty principle follows naturally. (So we are not in kooksville, with black hole assemblies directly playing the part of atoms in a “larger” universe and so on!)
Specifically, the AdS/CFT aspect of the duality means that energy quanta in the emergent universe correspond to equal-mass black holes in the contracting universe, and mass in the emergent universe corresponds by duality to radiation. Also, one assumes the duality accounts for the discrete spectrum of possible fermion rest masses (perhaps corresponding to a discrete spectrum of possible closed black hole assemblies?)
Clearly this model is driven in part by exterior forces, and is thus not a perpetual motion engine: dark energy corresponds to gravity on our abstract higher dimensional “sea shore”, and the sideways vector field Sean recently discussed corresponds to the opposing force of the “shore” itself.
One obvious objection to the model is that in each cycle essentially all mass-energy is packaged into units many orders of magnitude larger than the Planck units the mass-energy originally comprised, probably hundreds of billions of solar masses, which suggests the cycle must soon “run out of steam”.
There are at least two ways round this – Firstly if the number of Planck units is infinite, then dividing that number by a finite scaling factor still leaves an infinite number of black holes. I must say for various reasons I don’t find that explanation at all satisfying, especially the assumption of an infinite number of Planck units.
However, I was amazed when two or three people in this thread have mentioned that the Many Worlds interpretation is respectable, and actually equivalent to QM. I had somehow previously formed the impression it was generally considered a marginal idea at best, and it always seemed to me an absurdly extravagent way for the Universe to behave!
But a Many Worlds interpretation could be just what is needed to keep the supply of black holes steady between alternating dual cosmic generations, although the vast numbers involved defy the imagination.
Every parallel universe that, loosely speaking, forks off “ours” must evolve in the same way to little more than a collection of remnant black holes, and in the asymptotic stages where everything flattens out who is to say that the parallel universes might not reconverge?
Note also that in the extended stage each black hole may be causally disconnected from any others, so no observer at any given location seeing a neighbouring hole come back into view as the recollapse got underway could be sure that this hole had always been in the same cosmos! Related to this is the question of more than 3 space dimensions, which for lack of space I haven’t discussed (along with several other considerations).
But in parting here’s one more thing to ponder. The alert reader may have noticed a similarity of this alternating dual model with none other than photons. And who knows, although photons can be adequately modelled by dual electric and magnetic fields or “sum over histories” integrals, perhaps intrinsically (and of course far beyond our ability ever to observe even in principle) they have a more fractal structure and evolve internally in a manner somewhat resembling the model we have described.
One final note, for fellow amateurs reading this and who may not be exactly clear on what “duality” means: It is an alternative consistent arrangement of the whole, rather like those ingenious pictures that show, say, a bowl of flowers and are then seen to show at the same time an old man’s face. Al Seckel has a website devoted to these at http://www.illusionworks.com/ .
Regards
John R Ramsden (jhnrmsdn at yahoo co uk)
2008-03-19
P.S. I was very sorry to read that Arthur C Clarke died this morning, at the age of 90.
Among other things, it means he’ll miss the forthcoming film of his book “Rendezvous with Rama”, due out next year.
( http://www.rendezvouswithrama.com/ )
Sean C rashly said: “I’ll write more about it if I get the chance.”
PLEASE DO SO!!!!! I think that this is one of the most important misunderstandings in the community: that inflation somehow solves the problem of initial conditions. A lot of people find this belief very comforting, and refuse to examine it despite the fact that it is such a bizarre claim. It’s high time they were disabused.
Wild Ghost,
Not if time is a consequence of motion, rather than the dimensional basis for it. If it is motion causing events, such as the rotation of the earth causing days, then the arrow of time goes from future to past, so the wave function is future potential collapsing into past circumstance.
Paradoxically, the discussion here focuses on the area of the research in physics where the tremendous progress had place in last 30 years. It was triggered by R.P. Feynman (as usual) at 1982. The main difference compare with the “fathers” was the real life realization of the gedankenexperiments. It allows us to experience not only single atoms (known about 100 years) but to see a picture of the single electron. Moreover, we may not only to see the final result but to follow the process of the acquisition of the knowledge.
With respect to observables I don’t know how to present content of J.A. Wheeler & W.H. Zurek to grandmother. Roughly (oversimplification), we have two aspects:
1)Bandwidth; if it is too wide, you don’t know where to find the signal and how to extract it out of noise (you may use psy family story as illustration). For the same reason our natural sensors (eyes) are narrow bandwidth devices. That is about the variables observable in principle.
2)Gauge dependent variables connected with the internal symmetries; these are not observable in principle. Only Noether related quantities are observables. Apparently, it is enough (in some Ockham analogy with the bandwidth).
Regards, Dany.
John Ramsden on Mar 19th, 2008 at 1:49 am
Yes, it seems to go against Occam’s Razor. But it is more in keeping with an infinitely recursive structure, and many find this “no first causes” idea more satisfying than a single large cosmos popping out of essentially nothing purely by chance.
——————
This of course has that “it’s turtles all the way down” sort of logic to it. I think the “other cosmologies” are configuration variables for various amplitudes in the grand path integral. These amplitudes are “eiselected out,” and so their overlap with the amplitude for the observable is decoherently reduced to zero. This grand path integral is from a set of inequivalent vacua states to the Minkowski spacetime at conformal AdS infinity. From a “timeless” perspective the path integral is “all there is,” where this exists in a “bulk,” such as in 11-dimensional M-theory. The observable universe is a process which takes one nothing, the set of unitarily inequivalent vacua, to another nothing which is the Minkowski void at conformal infinity.
Lawrence B. Crowell
John, Lawrence,
Wouldn’t a many worlds scenario, branching off an infinite series of universes eventually dissolve into total chaos? If they interact at initiation, then it seems likely they might interact over time. Solving one problem can’t create more problems for it to be an effective solution.
Lawrence B Crowell wrote (#70)
>
> This of course has that “it’s turtles all the way down”
> sort of logic to it. I think the “other cosmologies” are
> configuration variables for various amplitudes in the
> grand path integral. [..]
Many thanks for your comments on my post #66 Lawrence. (That post was possibly longer than some might think proper here, and if so I apologise.)
Although your explanations in #40 and #70 certainly make sense, they do raise further questions. As these are doubtless due in part to my faulty understanding, please don’t think of this reply as solely an attempt at rebuttal by an obstinate amateur blundering on with their misconceptions and heedless
of expert input, even if it may seem so.
Firstly, your explanation in #40 involves boundary conditions at infinity, and in the context of this discussion my impression (perhaps reading to much into what is after all a routine assumption) was that you meant this to hint at excluding the possibility of anything “beyond”.
However, what is infinite in one metric may become finite in other useful metrics (even if new infinities may pop up in place of the old). But if in this way infinite boundaries are ambivalent in formal models, does that not suggest a possible ambivalence in what appear to us unbounded aspects of nature
itself, especially one causally connected patch? In particular, doesn’t it challenge the very idea of a single all-embracing infinity even existing?
This leads to my next question. You mention “turtles all the way down”; but in a multiverse model, assuming we have no special place, one can add “turtles all the way up”, in other words not exclude the possibility of “force majeure”.
The very appearance of an apparently uniform influence throughout the Universe strongly suggests exactly that, and is how dark energy helps drive the “alternating dual” dynamics in the model I proposed.
But the words “up” and “down” here (not to mention “turtles”!) can be misleading, if they suggest a crude picture of “bubbles within bubbles” and so on.
Duality seems a more flexible concept because it allows one more readily to think of everything being on the same footing, even if at any given scale and standpoint some phenomena come to the fore and others are imperceptably small or large or, generally speaking, unobservable in one’s current intrinsic
setting.
You also mention a “grand path integral”, as representing the totality of reality. Although the dynamics you describe looks sound isn’t every photon, also modelable by a path integral, it’s own master so to speak despite the existence
of other photons? Surely that in itself is circumstantial evidence for the view that everything is relative, and no one dynamic process can be said to directly control all else.
All that said though, it’s obvious your explanation is a good example of how dynamics should be formally considered. So I’ve saved your posts and will re-read them now and then until they too become an almost unconscious part of my way of thinking.
John Merryman wrote (#71)
>
> Wouldn’t a many worlds scenario, branching off an infinite
> series of universes eventually dissolve into total chaos?
What counts overall is the small residual “structure” that remains at the boundaries of these worlds (or “arenas” as some prefer to call them in multiverse studies) and interacts between them.
In fact, arguably one can think of an arena as comprising nothing *but* boundaries, both large and small, and its dynamic evolution as merely the recombination or reconfiguration of these.
I think Lawrence alluded to something like this in referring to boundary conditions at black hole event horizons and the AdS (Anti-de Sitter) horizon at infinity.
> If they interact at initiation, then it seems likely they might
> interact over time.
Correct – In the dual model I summarized “they” are simply two views of one and the same thing but with various characteristics such as mass, temperature, and time all rearranged, or scales “inverted”.
Remember the clever pictures I mentioned, which show two different things at once (You *did* read all my post didn’t you, and not wimp out half way through 😉
All the dualities I listed have been known about for years. They can be useful “dictionaries”, by which one can convert a problem hard in one setting into an equivalent form tractable in another.
One of my basic points is that knowing in detail about late evolution, by using general relativity, a sound grasp of the duality would allow one to make deductions about the early stages of the dual early evolution, i.e. the Big Bang.
(Veneziano and Gasperini have been studying these pre-Big Bang scenarios for years, and I think it was Veneziano wyho discovered scale factor duality. Gasperini’s web site seems to indicate that work has tailed off somewhat recently, but it may just be the baton has passed to others.)
John,
I definitely read all posts here. Understanding them is another matter.
My deeper ambivalence about the many worlds concept concerns one of the points I’ve made about time. The many worlds model says that nature doesn’t decide between potentials and at every fork in the road, all alternatives happen as different realities. This presumes that information, as well as the energy manifesting it, goes from past to future, so that at every current and past circumstance, the potential alternatives branch out to all possible subsequent events. My point about time is that while the energy goes from past to future events, the information that is these events goes from being in the future to being in the past, whether it’s the rotation of the earth forming specific days, or strings manifesting as specific vibrations. The information that is any particular day or vibration, is first in the future and then in the past. The result is the collapsing wave model, where all potentials come together and what prevails, as the energy input collides, is the actual. Consider Schrodinger’s cat: Rather than just view it from the perspective of the observer, where the cat is both dead and alive until it’s revealed, consider it also from the perspective of the wave of events. First the quantum event, then the poison, then the cat, then the opening of the box. As these events occur, the wave collapses, but the information doesn’t travel any faster then the wave collapses. It’s like a star exploding right now, about ten thousand lightyears away. We have no way of knowing until the wave of energy reaches us, because it is still ten thousand years in our future. The timeline for the information of this event is from our subjective future, to present to past, as the arrow of time goes from what comes first(events being in the future) to what comes next(these events being in the past).
So since time is not a fundamental dimension, where both energy and information go one direction, we don’t need to assume every potential must imply an actual.
One more comment, basically a continuation of #73, to explain how the duality picture seems similar in a way to Lawrence’s explanation. Then I really must give it a rest, or Sean will be on my case for hogging the discussion!
In #40 Lawrence sketched a picture of (if I understand it) one eigenstate dominating the others, which then cancel out and fade into the background. Now eigenvectors are basically symmetric or “stable” solutions, a classical example being the way a rotating rigid body evolves to rotate about a principle axis, and this symmetry is also a key aspect of my proposal.
A non-trivial duality of the kind I envisage is a generally a many-to-one transformation, something like a Fourier transform, which therefore “mixes” configuration values of one space to form discernable structures such as particles and fields in the dual space.
That means randomness in a space is transformed to dual randomness. In particular an empty space is dual to another empty one. Likewise a space containing randomly arranged structures also maps, for all practical intents, to an empty one because those structures are jumbled up throughout the dual space. Similar to Lawrence’s eigenstates that don’t make the grade, their dual images are simply lost in the background.
Now everyone agrees that black holes will one day be the only surviving structures in our intrinsic arena (i.e. the universe we percieve directly), aside from random radiation. So it follows that if an arena dual to it is to evolve to contain any interesting structures then the black holes in ours must be arranged symmetrically WRT the dual transform.
It’s true they are symmetric in time, by simply lasting so long, and their shape in space is also obviously pretty symmetric. But it seems to me that even more symmetry, collective symmetry if you like, may well be required to produce “compact” dual images, and that means it isn’t good enough for them to be scattered through their intrinsic space at random – They must somehow arrange themselves in symmetric chains almost like molecules.
As luck would have it, another benefit of black holes collecting and held in symmetric chains is that their degrees of freedom are thereby reduced. This I argue reduces the collective entropy of their dual structures, which is what I meant by “resetting the entropy clock” in the emergent dual arena.
Also, although the dual emergent structures may be intrinsically Planck-sized strings as conventionally understood, and behave as such, they are derived from vast macroscopic strings in the original arena. These latter beasts aren’t the exotic long strings one occasionally reads about in New Scientist, but are precisely the chains of black holes held in place by familiar forces (see my post #70), which cause these strings to “vibrate” over intrinsic eons and generally behave just like a conventional string – because in effect that is what they are!
Finally, the fine tuning I referred to is the condition that black holes in late evolution hang around long enough to form these supposed strings. If not
then no interesting dual arena emerges. But turning the argument round, one assumes in this rubric that our arena started out (and of course still is) dual to a later-stage arena, which in turn means that enough black holes *did* survive in that.
If we’re *really* lucky, and happen to live in one of stable sequence of duals, then that might (with a sound understanding of the dual transform) allow even more delicate fine tuning, which could one hopes be confirmed experimentally by the values of physical constants.
(I’m skeptical of the notion that fundamental constants can differ between dual arenas. But then until the nature of the dual transform is clarified, who can say which constants *are* fundamental?)
Anyway, I’ve rambled on quite long enough and will call it a day.