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The Paradoxes That Threaten To Tear Modern Cosmology Apart
KentuckyFC writes Revolutions in science often come from the study of seemingly unresolvable paradoxes. So an interesting exercise is to list the paradoxes associated with current ideas in science. One cosmologist has done just that by exploring the paradoxes associated with well-established ideas and observations about the structure and origin of the universe. Perhaps the most dramatic of these paradoxes comes from the idea that the universe must be expanding. What's curious about this expansion is that space, and the vacuum associated with it, must somehow be created in this process. And yet nobody knows how this can occur. What's more, there is an energy associated with any given volume of the universe. If that volume increases, the inescapable conclusion is that the energy must increase as well. So much for conservation of energy. And even the amount of energy associated with the vacuum is a puzzle with different calculations contradicting each other by 120 orders of magnitude. Clearly, anybody who can resolve these problems has a bright future in science but may also end up tearing modern cosmology apart.
> What's more, there is an energy associated with any given volume of the universe. If that volume increases, the inescapable conclusion is that the energy must increase as well. So much for conservation of energy.
???
Why cant the energy just be less dense?
Got it.
The only thing that's tearing cosmology apart is the gradual expansion of space.
If there are no particles moving at all, how does empty space have energy? It's the textbook definition of lack of energy. Empty space cannot impart energy on matter and it can't spontaneously create matter. There's some theory about virtual particles but their net energy is zero when they combine so that's not it. Can anyone explain why empty space has energy?
Perhaps the most dramatic of these paradoxes comes from the idea that the universe must be expanding. [...] yet nobody knows how this can occur.
Since when did "paradox" became a synonym for "unknown"?
Yeah, nobody knows how space expands, but how does that make it a "paradox"?
Oliver.
Is there some reasons physicists have ruled out that photons simply lose energy through some mechanism as they propagate? And whatever this mechanism is (like dark matter) simply isn't observable with current technology at short distances, but becomes obvious at long distances?
Or maybe dark matter IS visible, but only over long distances, and "cosmological red shift" is actually due to the photons interacting with dark matter?
Come on already! This isn't primary school. I learnt this when I was young.
Yet you continue to visit, click, AND post.On almost every article!
How do you do it?
It's also far from certain that the energy contained within the universe increases as the universe expands. In fact it would make more sense that it doesn't, and "thins out" as the result of expansion. (so the average energy per cubic megaparsec declines over time)
throw-away comment, here :) i did a funny little bit of experimenting a couple of years back, when someone posted here an article about the density of deep space (the number of atoms per cubic metre) having been measured. anyway, remembering my o-level chemisty and i went, "hmm... that's interesting: i wonder if there's a relationship between that particle density and avogadro's constant.
so... i went... density = 7 * 10e-26, avogadro's const = 6.023 * 10e23, multiply the two together you get 4.2154. just for fun take the cube-root and oo! you get 1.6153982. now, to within experimental uncertainty of the measurements made of the density of deep space vacuum, that number should instantly be recogniseable +/- a bit, as the golden mean ratio (1.618 etc etc).
so we have a relationship - which has absolutely no quotes real quotes meaning whatsoever [ traditionally called "numerology" in a disparaging way in the physics community... ] between the density of particles in vacuum, avogadro's constant, and the golden mean ratio, in a formula that has very low kolmogorov complexity (https://en.wikipedia.org/wiki/Kolmogorov_complexity). which, as i do not have the kinds of hang-ups that the physics community has about these kinds of things, i find to be... beautiful.
and that's in and of itself enough for me. i don't care what the physicists say :)
anyway, as this is slashdot, i thought i'd happily derail the conversation with a nice bit of random semi-related nonsense, and see if anyone notices...
I really wish Slashdot would stop accepting their links
paradoctored
Coming up with better explanations is what science is for.
Summary: headline is sensationalist clickbait, Slashdot editors are whores, Netcraft confirms Slashdot is dying.
Yet you continue to visit, click, AND post.On almost every article!
How do you do it?
And you reply to your own post too...
I know the answer, you are a robot, I mean, I am a robot, oh god.... NO CARRIER...
http://www.simulation-argument...
But, that does not make it any less real-seeming to all of us being simulated...
And of course, the universe simulator could be simulated, etc....
It might be simulated turtles all the way down. :-)
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
As entropy in the universe increases, so does the amount of space.
Yep. This is the reason I check in with the 'electric universe' folks now and again, to see what their explanations of some of this stuff is. Not that I think they're the ones with correct theories, but the 'mainstream' scientists sure seem to be in love with gravity to explain everything.
Oh, and if I hear another scientist go on and on about how theories should be "simple and beautiful" I shall vomit. The universe doesn't care what humans think is simple or beautiful. Frankly, the universe being an insanely complex clusterfuck would explain a lot.
The expansion of the universe is fueled by a continuous transition to lower-energy vacuum states. Unlike the normal "false vacuum" model, though, there are a lot of these lower-energy states, which become closer and closer together until they reach a limiting value.
The graph of these states would probably look familiar - it's similar to the electron transitions for the hydrogen atom, only with the orbitals replaced with "time since the Big Bang". The net result matches the lower value of the vacuum energy... and there's the possibility that this also explains inflation as being equivalent to the transition between n=1 and n=2 (whereas we're currently at something on the order of n=10^35).
Granted, there's no guarantee that I'm right (and in fact I'm probably not, since I have no formal training in cosmology), but it looks like a model that fits the current knowledge.
Slashdot editors aren't whores. Whores give a fuck.
(yes, in return for remuneration; it's a humorous statement to make a satirical point, not intended for complete accuracy, ya pedantic pock-faced whoresons)
Those aren't paradoxes. So space is created. How is that a paradox? Did someone say space is not allowed to be created?
So energy is created. That violates conservation of energy, but conservation of energy is simply a law that we formulated from experience, and later proved using Noether's theorem by assuming that the laws of physics are time-invariant. Well, it's not valid to extrapolate from our small-scale experiences to the universe, and the laws of physics probably aren't time-invariant at cosmological scales.
Nobody really knows how to calculate the energy of the vacuum, and that's why we have to use renormalization. The 10^120 figure is really a very rough ballpark estimate using dimensional analysis. There's not any solid theory to back it up.
Noticing does not mean we care :).
Karma -= 100...
It has been known for quite some time that energy is difficult to define rigorously in General Relativity. A good explanation can be found in this post by CalTech physicist Sean Carroll. Key point:
As a simple example, imagine a photon traveling through an expanding universe in a region with no other matter or energy (dark or otherwise). The expansion of space stretches the wavelength of the photon (cosmological redshift, which is distinct from Doppler redshift), causing it to lose energy. The photon loses energy with nothing around it gaining. Energy is lost because spacetime itself is changing, so Noether's theorem doesn't apply.
Some people don't like to admit what they don't know. That includes some physicists.
Then I did a google search and realized it was just my own ignorance,
here's a huge list of unanswered questions on wikipedia:
http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
How can we definitively tell if the vacuum over there has the same energy density as the vacuum over here?
Further, how can we tell if the energy we think we find in vacuum here isn't energy that arises from particulate contamination? Or, for that matter (ha) is coming from somewhere else? Has someone managed to (a) create a perfect vacuum and (b) measure its energy and (c) determine that whatever was measured as appearing at X, definitely hadn't disappeared from all the possible Ys? Somehow, I doubt it. If for no other reason than our access to some of the other Y (say, around Andromeda) is... limited. As well as non-contemporaneous -- if something disappeared from that region, to appear here, we wouldn't have any indication it had happened for about 2.5 million years. And even then, our ability to measure vacuum precisely at that distance... not so good.
My (admittedly not very deep) understanding of vacuum is that it is defined by a lack of content, and that a perfect vacuum would be defined by a perfect lack of content -- and were that simplistic idea correct, then I don't see why how much perfect vacuum there is has any bearing at all upon the total amount of energy.
And, if vacuum is indeed empty when perfect, but we think there is energy detected in what we consider a perfect vacuum, then perhaps we're simply misinterpreting the goings-on within an imperfect vacuum. Perhaps there is more to get rid of than the molecules and particles we know of at present.
Or, perhaps space is infinite and at least somewhat plastic to start with, and our situation (going with the idea that the space we can observe seems to be expanding) is more like adding a thimble of water to a planetary ocean (let the ocean conceptually be infinite for the sake of an example.) Perhaps space over there is contracting, while space over here is expanding.
My own position is that any cosmological proposal that includes the phrase "arose from nothing" or similar is probably better filed under astrology until actual evidence is found of the idea -- not possible precursors or echos, but an actual example of what is being described. We seem to be pretty clear on the idea that matter and energy are essentially interchangeable, and we have no experimental data that proves stuff arises from non-stuff, so at least at this point, I see no reason to take an assertion of "arose from nothing" seriously.
I've fallen off your lawn, and I can't get up.
Even professional physicists like some good numerology sometimes.
Also, just so we're clear, you took a number e-26, multiplied it by a number e+23, and you ended up with a number e+0?
Don't blame me, I voted for Baltar.
It's virtual turtles, you insensitive clod!
I've fallen off your lawn, and I can't get up.
What if it isn't expansion but the weak interaction over vast differences between light and matter that it passes? ie: accumulated gravitational effects of near misses with other particles.
Even professional physicists like some good numerology sometimes.
Also, just so we're clear, you took a number e-26, multiplied it by a number e+23, and you ended up with a number e+0?
Ah, I see what you did there: you lost a factor of 100.
I notice that 100*0.04215 = 42
Units. I could just as easily started with the density = 1 or density = pi. Units matter, your conclusions don't work in ALL units. Then taking the cube root of a number just for fun? Do you mean to say "just to get the answer I want?" What is the point of this series of calculations?
Proportional displacement. If space/time is expanding, is it also trying to displace the matter that occupies it? In other words, is gravity a pull, or a push! Perhaps it's a relative to the distance between space/time and matter that determines which supersedes what; meaning, matter coalesces into galaxies, but with enough space in between galaxies, they push each other away?
It's "new math." You don't have to show your work.
"National Security is the chief cause of national insecurity." - Celine's First Law
Zero is far more plausible than infinity.
Maybe check in with actual scientists from time to time again. EU folks spend so much time talking about mainstream scientists instead of science, and yet get that blatantly wrong. Astrophysics isn't just about gravity, as there are whole courses, books, journals, conferences, and sessions at more general topic conferences dealing with plasma physics in space. There was even an article just a couple days ago on Slashdot that directly talked about the effect of plasma in intergalactic space on light signals, and gave enough context (or just look at some of the comments) to learn more about the topic and figure out exactly to what limits those effects are noticeable vs. inconsequential.
I remember something like this vaguely coming up in a comment before on Slashdot, and I hope it was not you making the same mistake, as comments spelled out in those cases clearly that it was a case of density * avogadro's constant / number of atoms gives you the average atomic mass, which is pretty close to 1 for deep space.
so... i went... density = 7 * 10e-26, avogadro's const = 6.023 * 10e23, multiply the two together you get 4.2154. just for fun take the cube-root and oo! you get 1.6153982
No, you multiply those two numbers together, and you get 0.042, which is also a meaningless value because you now have kg/m^3/mol... and it is not like deep space is anywhere near a constant density, as there is a large variation in density and temperature (read about warm intergalactic medium vs. hot intergalactic medium).
I don't know how this got modded up. Not saying it should have been modded down, but you just took two random numbers, one of which doesn't even have that deep of a connection to space as you imply, and multiplied them together incorrectly, and tried to draw vague conclusions from that.
WTF? I know Slashdot really likes to mod people up to +5 when even when they get basic physics and science wrong, but when their premise is a basic multiplication error you should be able to catch without a calculator? If it is one thing if seeing numbers in a post "excites" you, but go somewhere else if you are aroused by wrong numbers (e.g. rule 43).
Zero is far more plausible than infinity.
The trouble with that statement is that it never reaches either infinity or zero, it is an asymptotic thing not a linear thing.
Maybe the universe is not expanding but instead matter is shrinking.
At the very short distances, of the order of Planck's length, it is likely to be the strongest. Which is probably one of the reasons why efforts to quantize gravity are doomed to fail.
When hubble was making his observations, there were a whole series of alternative proposals to explain spectral redshift. To the best of my knowledge, these have all been abandoned, but a viable alternative to expansion wraps up many of these paradoxes, and honestly, makes the universe much less depressingly overcomplicated.
I have often wondered, what if it's all wrong ?? What if red shift does NOT equal distance or speed of expansion ??
What if light 'ages', and loses energy, and hence undergoes a non doppler red shift ? Why do cosmologists say this kind of thing is impossible or stupid, when they can't prove it either way ?
Do black holes really exist, or is it just an asymptote within the formula which allows (theoretically) it to occur ?
and what is up with magnets?
I'll bet its that damned Matthew McConnaughey again, always starting shit from another dimension.
We just don't understand everything about blue shift as much as we think we do?
seems to me that any time i have seen an explosion there has been a large bubble or series of bubbles, and a bunch of instant energy just heading out.
Jeoin
I think what is called Dark Energy maybe some kind of particle that creates space-time cells when it decays.
If so that means expansion of the Universe must stop when it runs out in distant future and also means there is no problem with conservation of energy.
Currently there are observations going on to determine amount of Dark Energy billions of years ago in the Universe.
I think they will find it to be much higher than today.
Also from that data it maybe possible to calculate when expansion of the Universe must stop.
OP says "paradox" but the issues discussed in the paper are not strictly paradoxes, just contradictions. There is a difference.
If you say it's black and I say it's white, that's not a paradox but a contradiction. If one theory says it's red and another theory says it's green, again that's not paradox but mere contradiction.
God dun it /s
* Why does something exist rather than not? * What is time? * Why do people laugh at Don Rickles?
If the universe is torus(donut) rather than a spheroid then the bit in the middle can get bigger without creating a vacuum.
Inflation solved, you're welcome.
But if your theory says it should be black but your theory has an underlying assumption of being white, that is a paradox, not merely a contradiction.
Sadly, generally accepted cosmology theory is a mishmash of general relativity and quantum mechanics which are theories that contradict each other on some predictions. For example FLRW from general relativity predicts the existence of a cosmological constant or some sort of dark energy and suggests that a universe that is expanding at the currently observed rate has a range of values: let's call it black, but cosmology relies on a data from quantum mechanics which given other observations suggests these constants have a completely different range of values orders of magnitude different: let's call it white.
Sure it's two different theories GR and QM that disagree, but oddly, cosmology theory is a mishmash of the two and thus is more paradoxial than particle physics which knows that GR and QM disagree at small scales about gravity yet are hopeful for a GUT (grand unified theory) at some point to make testable predictions. Most cosmology assumptions aren't awaiting a GUT and you might even say they are effectively embracing the contradicting predictions of GR and QM and blindly marching on.
...the universe is not expanding, but the observers instead are in an "apparent shrinking" process, which is only manifesting itself in the form of current observations?
Does that fly in the face of what is presently known?
Don't shoot the messenger, there is no physicist anywhere around here, just a thought challenger ;-)
I think it is time to revise the foundations of both our great theories, quantum mechanics and general relativity. This has become more and more evident in the recent decade, but it has been obvious almost from the beginning, since the two theories have been known to be incompatible already since the Solvay conference, if not before, and I think I can see some signs that efforts are being made to move away not only from GR, but also from QM.
The big problem is of course the inescapeable success of both theories; we have yet to discover a clear example of a contradiction of either theory. To my mind, this suggests that it is necessary to be willing try to go beyond the traditional interpretations of the fundamentals of both. There has already for many years been massive efforts to try to modify GR to be more 'quantum', which have not really brought anything obvious to light, so perhaps it would be worth trying to revisit the foundations of QM? Basic tenets like the collapse of the wave-function and similar concepts have always struck me as far too glib to be real explanations. I think it is perfectly reasonable to expect better than that, something that somehow feels more convincing. Not necessarily simple or intuitive in the naive sense, but convincing. Something like the original explanation for Heisenberg's indeterminacy: that because we observe by means of particles, that are actually waves, there is a limit to how precise our observation can be. Please note, I'm claiming that this is the correct explanation, but it illustrates my point: it feels right because we feel we understands the way waves work, and we can perform calculations on much a finer scale than the observation by means of waves permits.
I think a lot could probably be resolved by understanding more clearly the basics of QM; all the things that feel too much like glib assumptions, questions like what is a particle in terms of physical space (declaiming that it is 'the wave-function' or similar just sidesteps the issue), and what is time (talking about entropy involves a circular argument, IMO) and others. As you can see, I have stated these two in terms that have some bearing on GR; that is not by accident - I think GR is fundamentally more correct than QM.
There is absolutely nothing that says the energy of the universe must increase just because the volume increases. Total energy in the universe is constant, but the energy DENSITY decreases with volume. This is the concept of "heat death" due to expansion of the universe. Energy concentrated in lower volumes (stars) created by converting potential energy (gravity) into heat (fusion) eventually dissipates (law of thermodynamics). As the universe expands (volume increases) so does entropy as the energy AND mass density of the universe decrease. Lower mass density means new stars are less likely to form, and no new energy is being created. Voila, eventual heat death as there are no longer any means to concentrate energy into a small space.
The universe continues expanding and the temperature of the universe falls as the energy density decreases.
Why the fuck is this so hard for these people to understand?
What's science's answer to this one?
1. Any sufficiently advanced civilisation can create a simulation (or more) on a grand scale.
2. In a simulated world, intelligence and construction may arise, eventually leading to sufficiently advanced simulated civilisations
3. (... after some thousands of recursions, also recognising that there is plenty of 'time' for that because time is an internal variable of the universe in question...)
The big Q:
What is the likelihood that in the vast tree of simulated universes, we are sitting at the root?
Could it be that as a simulated civilisation advances, and invents the microscope and the telescope, and intelligent species proliferate, the simulatING civilisation has to throw more and more hardware at the problem? Or has to invent physics on the go? E.g. pre-Newton and pre-radiotelescopes, a Newtonian world would have perfectly worked, from the viewpoint of the humans, with 'rendered' stars; pre-microscope, maybe bacteria etc. didn't need to exist. The simulator just simulated some sickness or reaction. When the loop tightened, they had to invent something.
Maybe science stops when there is enough evidence that some things just can't reconcile with one another, or when more and more investment is needed for less and less impactful findings (bosons, very remote galaxies etc.). Maybe a team of scientists one level up are playing pranks or feeling creative. And some other scientists tie their hands and just start some cellular automaton to see where it leads to.
Isn't thinking this the equivalent of the geocentric or heliocentric world view?
Still, as they find slowly their way through what Plasma in space can achieve, mainstream science is blinded by Gravity only suppositions turned into "reality" with an increasingly set of fudge factors. TFA just list a small number of them. But talk someone on the "mainstream" - including just self-presumed scientifically educated persons that the Big Bang perhaps did not take place, and point to the political and social movements inside Science that led to its conformation, and you are as an "heretic" as someone who tries to tell a fundamentalist Christiant that Hell or Heaven may not be the way he have been told.
-><- no
Is this just grant grabbing bullshit? Confuse your funders so much, that they hand out cash, because whatever you are pushing is really sounds so complicated that it must be worthy.
Funding decisions, at least in the US and UK systems, are made based on reviews by other scientists in similar fields, some of which have self-interest reasons to call out what they are reviewing as BS if they can and it helps make their own projects get funded instead.
Modern cosmology be like: http://www.youtube.com/watch?v...
It'a the only discipline where 120 orders of magnitude is a slight disagreement.
Taking your comment seriously, :-) are you suggesting simulated seems to imply fake, but virtual implies essentially the same? Maybe there is some related change in social consciousness on these topics reflected by "virtual" becoming a more commonly used word?
From Wikipedia:
http://en.wikipedia.org/wiki/V...
"Virtuality, the quality of having the attributes of something without sharing its (real or imagined) physical form"
http://en.wikipedia.org/wiki/S...
"Simulation is the imitation of the operation of a real-world process or system over time."
Virtual can also potentially be a subtype of simulation:
http://en.wikipedia.org/wiki/L...
So yes, simulation does seem to imply more fakeness (imitation) than virtuality (which implies the essence is still there).
So, I stand corrected! Thank you, fyngyrz! It's virtual turtles all the way down. :-) Sorry for being insensitive about that!
BTW, I watched this excellent video last night of "Inventing the Future" with Robert Tercek, interviewing Bruce Schneier and Julian Sanchez about pervasive surveillance, drones, and related social changes, and the advertisements were all about Microsoft HoloLens:
"Next Future Terrifying Technology Will Blow Your Mind"
https://www.youtube.com/watch?...
A decade or more ago I saw a video of similar augmented reality demo (Steve Feinberg walking around Columbia university?),.
http://www.cnet.com/pictures/g...
"Steven Feinberg (left), a professor of computer science at Columbia University, created the first outdoor mobile augmented reality system using a see-through display in 1996."
But Microsoft HoloLens looked so much more impressive and integrated, and I can imagine with better head tracking technology like for Oculus Rift, that it would work better. Slashdot has an article on HoloLens from eight hours ago:
http://tech.slashdot.org/story...
But in the context of this discussion, Microsoft's "HoloLens" show how the line between "physical" and "virtual" can start to become blurred.
http://www.microsoft.com/micro...
"The result is the world's most advanced holographic computing platform, enabled by Windows 10. For the first time ever, Microsoft HoloLens brings high-definition holograms to life in your world, where they integrate with your physical places, spaces, and things. Holograms will improve the way you do things every day, and enable you to do things youâ(TM)ve never done before."
Reminds me a bit of Red Dwarf and Arnold Rimmer. :-)
Perhaps many religions are right, and for our situation at least, an omniscient "god" really does know everything we do? And if every timestep of the virtuality/simulation is recorded somehow, then perhaps nothing is ever lost -- except in a stegnographic sense, or perhaps in the sense of having no more significant runtime devoted directly to its continued processing as an entity as it has lost obvious coherence?
People talk about how any singularity might be more about humans merging with machines then machines taking over, and one can wonder if, the first time, if there was one, virtualizing was more about a merging of physical and simulated/computed/virtualized as with HoloLens than one or the other?
Anyway, just random thoughts. It is in the nature of virtualization that you can never be sure what layers really surrounds you, so we may never know...
One other tangential issue:
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
The red-shift is a function of distance, not speed.
"Clearly, anybody who can resolve these problems has a bright future in science but may also end up tearing modern cosmology apart."
But what? Real scientists love it when their models blow apart.
OP says "paradox" but the issues discussed in the paper are not strictly paradoxes, just contradictions. There is a difference. If you say it's black and I say it's white, that's not a paradox but a contradiction. If one theory says it's red and another theory says it's green, again that's not paradox but mere contradiction.
But I'm here for an argument!
"What the American public doesn't know is what makes them the American public." -Ray Zalinsky (Tommy Boy)
Looks mostly theoretical.
https://www.researchgate.net/p...
"The ability to delude yourself may be an important survival tool" - Jane Wagner -
The simulation argument is nonsense that is only plausible to people who either haven't given it any thought or don't know any physics: http://www.tjradcliffe.com/?p=...
Blasphemy is a human right. Blasphemophobia kills.
On The Thermodynamics Of General Relativity.
http://vixra.org/abs/1412.0270
I have been looking for constructive feedback on these new ideas, so please do so if you have the time. I published this paper simply to get these new ideas out on the table for discussion by the community while I turn my attention to my next paper on solutions to the paradox of Special Relativity, and later the structure of matter and spacetime. The same solution fits all the open issues I know about.
Thermodynamic Unification Theory https://plus.google.com/u/0/+S...
One thing is obvious: you and I have not known the same scientists. Are you sure you've talked to scientists about that? It sounds to me more like people who are interested in the results of science and don't understand the process very well.
And, yes, gravity dominates over long distances. The strong and weak force are actually limited in range, and although electromagnetism is far stronger than gravity it isn't additive: add positive and negative charges together and you get something not strongly affected, and if you try to add only positive together (say) they'll both attract negative and repel each other, resulting in overall roughly neutral charge in a volume. Gravity is additive: put matter together and it will try to clump on its own (less so without electromagnetism to affect behavior at short range), and it will have an increased force over distance.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
When water "solidifies" at 0C (less energy), it "expands" its volume... This is not the only substance to do this. I think the problem with that "paradox" is that it is not a paradox at all. It is a reprsentation of the misconception that all "known" things follow the not-so common sense rule that less energy means contraction. 'Ya follow me? It does not break any rules (that I know of) when you understand why this occurs... i.e. Van Der Walls forces, etc.
As with many cosmological argument, that essay called "Imaginary Arguments" by TJ Radcliffe does not prove anything about a potential infinity of nested infinite universes. There is a key hedge there of "given what we currently know of physics". Much of physics (for example the Heisenberg uncertainty principle) is in essence a theory of what we could conceivably learn about the universe and beyond, not actual information on the universe and beyond. Likewise for saying we can see up to a certain distance of some billions of light years in space and time. That tells us essentially nothing about what is beyond those limits. We could, for example, be in an expanding bubble in a larger ocean of such bubbles -- but we could not tell using light-speed-limited electromagnetism. It would take, say, access to universe level bugs or debugger hooks to make an exploit that would let us travel beyond those electromagnetic limits in a human lifetime. :-)
This is where that essay goes off the rails, when i overgeneralizes the issue of what we can know with what might be out there: "Nor will it do to imagine alternative physics to fix all this up: insofar as the philosopher's argument is to have any claim on our attention at all, it must be based on what we know about the universe we actually live in, not some self-contradictory universe of a philosopher's imagination, where particles and computers behave in impossible ways."
That may be a useful sentiment by an observer about an observed box, but it is an overly limiting one when talking about things outside a box the observer appears to be in. At the very best, experimental physics can only tell us about the currently "observable" universe within a very small space-time bubble surrounding the current Earth.
So what if experiments are precise to many digits? When you are dealing with possible infinities and nested universes, anything is possible. It just does not matter how mind-bogglingly large the numbers are, or even if every universe can only simulate 0.5% of itself. The observable universe is already mind-boggling large. What are, say, a few trillion extra zeros tacked on to that regarding data storage needs or time needs for simulations to have billions of virtual turtles simulating nested universes some of the way down? :-)
Or in other words, from xkcd:
"A Bunch of Rocks"
http://xkcd.com/505/
Also, there are probably ways things could appear to be precise in some ways to a limited number of observers (like millions of Earth scientists), but not really being fully fleshed out. However, going down that rabbit hole involves many deep existential questions (like how can I know anything at all exists, or has existed, or will exist, how can I trust my memories, how many observers really exist, etc.) that most physicists may be better off ignoring, either career-wise or for mental health reasons. :-)
http://disciplined-minds.com/
"Upon publication of Disciplined Minds, the American Institute of Physics fired author Jeff Schmidt. He had been on the editorial staff of Physics Today magazine for 19 years. Following advice given in the book itself, Schmidt and free-expression advocates mounted a campaign that brought public judgment to bear on Schmidtâ(TM)s dismissal. Such justice is available to anyone not afraid to go public."
That said, such an essay might fairly criticize specific conclusions in "the simulation argument" itself, since much of that is indeed speculative related to "ancestor simulation" or best practices for living in one. But for anyone who has spent time using computer VMs, as well as the mathematics of infinities, the essay-as-is sounds fairly limited in its thinking.
Of course, even the notion of "infinity" has its controversies: :-)
"Dispute over Infinity Divides Mathematicians "
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
http://www.blacklightpower.com/theory-2/theory/cosmology/
But talk someone on the "mainstream" - including just self-presumed scientifically educated persons that the Big Bang perhaps did not take place,
I've been to talks to general physicists audiences that discuss alternative theories to the Big Bang. There was no screaming of "heretic" or attacking the presenter, there was instead an above average attendance, a lot of genuinely interested questions, and dialog. Maybe it helps because the talks were, "Here is an interesting idea..." followed by a detailed, quantitative discussion of the implications of the idea. There was no dwelling on the right or wrongness of more established theories, no holier-than-thou attitudes, lecturing people with broad assumptions on why they have certain confidence levels in different current theories. It was just instead a solid hour or two of discussing physics (not physicists or psychology, etc.), and a lot of people having fun looking at something novel, and an open dialog about pros and cons, successes and short comings, etc.
OP says "paradox" but the issues discussed in the paper are not strictly paradoxes, just contradictions. There is a difference. If you say it's black and I say it's white, that's not a paradox but a contradiction. If one theory says it's red and another theory says it's green, again that's not paradox but mere contradiction.
But I'm here for an argument!
I told you once.
The simplest calculation tends to be the most correct. We almost always start out with something complex, and as we find out more information, we can simplify the equation. The more complex something is, the more likely it is to be "brittle".
could the redshift of distant galaxies be attenuation of light?