[redhat-reallyp]

"it contains signs of a genuine conceptual breakthrough."

It contains claims of such signs, which seems to be the point of this fluff piece.

Alarm bells should go off when you read statements like this:

"...giving up space and time as fundamental constituents of nature and figuring out how the Big Bang and cosmological evolution of the universe arose out of pure geometry."

Ah yes, well that solves the mystery, doesn't it. The universe arose out of pure geometry.

A more concrete sign of the limitations of this work can be seen in the paragraph prior to the above quote:

"Physicists must also prove that the new geometric formulation applies to the exact particles that are known to exist in the universe, rather than to the idealized quantum field theory they used to develop it, called maximally supersymmetric Yang-Mills theory."

The problem is that maximally supersymmetric Yang-Mills theory conflicts with experiments (see e.g. http://news.discovery.com/space/lhc-discovery-maims-supersym...). This is why they hurry to qualify this point by saying:

"This model, which includes a 'superpartner' particle for every known particle and treats space-time as flat, 'just happens to be the simplest test case for these new tools,' Bourjaily said. 'The way to generalize these new tools to [other] theories is understood.'"

Well that's good, because they're going to need that generalization. Now all they need is to actually produce it.

This is the sort of thing that leads these gee-whiz models to end up on the ash heap of history.

Don't get me wrong, it would be fantastic if the amplituhedron revolutionizes quantum theory. But based on the red flags in this article, I wouldn't hold my breath.

[loup-vaillant]

> Ah yes, well that solves the mystery, doesn't it. The universe arose out of pure geometry.

That was a serious hypothesis before this. Heard about Tegmark's level IV multiverse? It's the idea that every mathematical structure just "exists", like "poof magic", and the simpler ones would, like, have greater weight. Kind of a literal interpretation of Occam's Razor, really. A corrolary is, the simpler the laws of physics are, the more probable the above hypothesis is. And suddenly we learn that the true laws of physics might be much simpler than we anticipated? This is huge.

Or not.

The idea of a timeless universe, where our subjective notion of time just arise from its structure has been around for quite some… time.

Likewise, Occam's Razor itself suggests that the true laws of physics are simpler than we think. Plus, current human laws of physics are either false or incomplete. I fully expect future physics to be further simplified. Claims of massive simplification are therefore not that surprising.

---

That said, I agree with your specific objections (the "work in progress" warnings).

[redhat-reallyp]

> That was a serious hypothesis before this. Heard about Tegmark's level IV multiverse?

Of course, I love Tegmark's speculative work. But that's all it is, speculative. It's like reading science fiction, one shouldn't confuse it with reality, at least not without evidence to justify that.

> It's the idea that every mathematical structure just 'exists', like 'poof magic', and the simpler ones would, like, have greater weight.

There's no evidence that this is how reality works, and there's no particular reason to think that it should work this way.

> A corollary is, the simpler the laws of physics are, the more probable the above hypothesis is. And suddenly we learn that the true laws of physics might be much simpler than we anticipated? This is huge. Or not.

All current evidence is that it's a fantasy, one which happens to be so attractive to some people that they're willing to suspend critical thinking to favor it, much as people do with belief in supernatural beings.

There are certainly cases where basic mathematical principles are expressed in a very direct way in the universe. Probability in quantum mechanics is one example, Noether's Theorem is another. But even in these cases, saying that some property of the universe arises from pure mathematics is misleading.

To boil down the objection, mathematics is a way to describe and model these phenomena, and shouldn't be confused with the phenomena themselves. Doing so is a map/territory style confusion.

If you want to say that the universe arises from pure mathematics, you then have to explain what sort of phenomenon pure mathematics is, that it is capable of producing such effects. To use my analogy, it would be a bit like saying "The topography of Earth arises from a pure map."

> The idea of a timeless universe, where our subjective notion of time just arise from its structure has been around for quite some… time.

That's a little different from the idea that reality is an incarnation of pure mathematics. In case, the fact that ideas have been around for some time has little bearing on their validity. Consider astrology.

> Likewise, Occam's Razor itself suggests that the true laws of physics are simpler than we think.

It does not actually suggest that in general. It can mean that in cases where an explanation contains unnecessary elements, but it says nothing about explanations necessarily being simple, or simpler than they already are.

> Plus, current human laws of physics are either false or incomplete.

I prefer to think in terms of models than laws, and models are always incomplete. The only complete model is the thing being modeled itself.

> I fully expect future physics to be further simplified. Claims of massive simplification are therefore not that surprising.

By your premise, actual simplification would not be surprising, but claims have no necessary correlation to actual simplifications.

Sorry to be picky!

[loup-vaillant]

> There's no evidence that this is how reality works,

Agree, to the extent we're talking rather direct evidence. It's like trying to distinguish between "poof magic" and "God did it". Quite impossible.

> and there's no particular reason to think that it should work this way.

Disagree. It's the simplest hypothesis to date that I know of. Therefore, I assign at least a non trivial probability to it.

> All current evidence is that it's a fantasy

You mean, current evidence speaks again the level IV multiverse hypothesis? Or something else? Anyway, please name three.

---

> [The idea of a timeless universe is] a little different from the idea that reality is an incarnation of pure mathematics.

As far as I know, we try to express the laws of physics with pure mathematics since Newton, if not earlier. I think it at least indicates a hope that reality may be accurately described by pure math. Provided we can, good luck trying distinguishing that, and "being an incarnation of math. No way we can test it from within.

> In case, the fact that ideas have been around for some time has little bearing on their validity.

Of course. I was merely pointing out that this idea was more ordinary that you made it out to be. To me, it is not sensationalist at all. It's something I more or less independently thought about in my teen years.

---

I maintain that Occam's Razor always suggest that the true explanation is simpler than the one we currently have. We're not logically omniscient. For any sufficiently complex explanation, there is always this nagging doubt that we missed something. Since by Occam's razor, the simpler explanation is the best explanation, the mere possibility of the existence of a simpler explanation is enough to suggest we're not there yet.

But it's no more than that, a suggestion. With enough double and triple checking, computer-verified proofs… we can be rather sure we did find the simplest explanation.

In the case of our current understanding of physics, we quite know for sure that we are missing something. In my opinion, that makes Occam's Razor's suggestion all the stronger.

---

> By your premise, actual simplification would not be surprising, but claims have no necessary correlation to actual simplifications.

I was just saying that when I hear someone claiming something that I don't find very surprising, I generally take that as serious evidence that the claim is true. I may not believe them, but they would at least get my attention.

---

> There are certainly cases where basic mathematical principles are expressed in a very direct way in the universe. Probability in quantum mechanics is one example,

Nope, not this one. :-) Quantum mechanics has to do with complex amplitudes, whose square determine the Born statistics. Plus, the wave function as we know it is deterministic. The relation to probability theory is tenuous at best. It serves more at hand-waving your way to the Copenhagen Interpretation, instead of biting the bullet and posit a collapse theory.

[redhat-reallyp]

> It's the simplest hypothesis to date that I know of. Therefore, I assign at least a non trivial probability to it.

I don't think it's simple at all. What is the role of "mathematics" in the conjecture - what is the word supposed to mean, and what about this new definition of mathematics results in the creation of physical realities? It seems unrelated to the discipline I know of by that name, which at its most general, is an approach to defining, analyzing, and using formal models. Essentially Tegmark is saying "all formal models (of a universe) must have a concrete realization", but why, and what is the point of introducing formal models into the picture - what role do they play?

It comes down to this comment of yours:

> we try to express the laws of physics with pure mathematics since Newton, if not earlier. I think it at least indicates a hope that reality may be accurately described by pure math. Provided we can, good luck trying distinguishing that, and "being an incarnation of math." No way we can test it from within.

To test a claim, the claim first has to be stated coherently. Mathematics is an approach we use to describe and model things, including the universe. It simply isn't some sort of creative force existing independently of the minds that can contemplate it. So when someone says "the Big Bang and cosmological evolution of the universe arose out of pure geometry", they are speaking incoherent nonsense, because "pure geometry" is simply not the sort of entity that can produce such an effect.

For this to make sense, someone would have to describe the nature of this creative force that they're calling pure geometry, and then the only connection to what we normally call geometry is that ordinary geometry would be a way of describing the effects of that creative force.

Geometry or mathematics are approaches to modeling, and are neither physical phenomena themselves nor the cause of those phenomena. As soon as someone claims that "it" is the cause of phenomena, they have committed an equivocation fallacy and begun talking about some other "it" which they haven't defined.

> You mean, current evidence speaks again the level IV multiverse hypothesis? Or something else? Anyway, please name three.

I was responding more to your characterization than to Tegmark's actual definition: if "every mathematical structure just exists" and "the simpler ones ... have greater weight", then it should have observable consequences, but we don't observe such consequences. For example, we might expect things to be constructed from pure Platonic solids, we might expect the subatomic realm to be less fuzzy, etc.

> With enough double and triple checking, computer-verified proofs… we can be rather sure we did find the simplest explanation.

Actually I don't agree with that. Finding simplicity does not always lend itself to formal process. But I'm saying that although Occam's Razor can remind us that a better explanation could be simpler than the one we currently have, it does not tell us that this is the case.

> I was just saying that when I hear someone claiming something that I don't find very surprising, I generally take that as serious evidence that the claim is true.

We differ on that. The fact that something is not surprising is not evidence. Many claims that are not surprising turn out to be false. To be more likely to believe something that seems unsurprising to you implies that you're choosing beliefs based on personal bias.

> Quantum mechanics has to do with complex amplitudes, whose square determine the Born statistics. Plus, the wave function as we know it is deterministic.

None of this contradicts what I was saying. Those complex amplitudes are complex to deal with superposition, and once that is taken into account, probability densities in QM are described perfectly by probability theory, so I don't know in what sense you mean that the relation is "tenuous". This has very little to do with one's position on interpretations, it's there in the math whether you like it or not.

[loup-vaillant]

(If you want to continue this conversation offline, you can reach me by e-mail —see my profile and my website.)

Okaay.

By "simplicity", I mean something like the inverse of Kolmogorov complexity. I know it's not very well defined, but given a Turing complete language, there is a proof that a given program is the shortest of its equivalence class —if it is.

I said "simplest", not "easy to grasp for a human brain", or even "simple". It's just that "poof magic we have simple mathematical rules on which the universe runs" is a simpler hypothesis than anything else I have heard from (such as the God Hypothesis). There's also a certain… elegance in positing that every set of mathematical rules are actualized. That way, we don't have to pick a particular rule, making the master program even simpler.

On Quantum Mechanics, okay, I guess you're right. Just remember that while amplitudes are out there in the world, probabilities are in the mind.

Do you think plausible that we could, in principle, find a mathematical model that perfectly describes the universe? To me, the answer is obviously "yes", even though I'm not certain that we could find this model in practice. Now, assuming our universe does run on math, it is quite impossible to test for different kinds of ontological existence. Do we live in a simulation? If the simulation isn't buggy, we don't stand a chance at root escalation, and we can't tell. Does the mathematical rules exist, like "poof magic", or do they need some exterior force or entity to be actualized? Again, we can't tell, because there's just no way out of our universe.

> For example, we might expect things to be constructed from pure Platonic solids, we might expect the subatomic realm to be less fuzzy, etc.

Maybe not. The actual laws of physics may be even simpler than that, despite the complexity that arise from them. We'll see when we find them. Occam's razor doesn't favour surface simplicity, it favours simplicity at the deepest level.

> The fact that something is not surprising is not evidence.

Indeed. It is prior information, which is just as important as evidence. Without prior information, you don't stand a chance at interpreting evidence. Data can't speak for itself.

> To be more likely to believe something that seems unsurprising to you implies that you're choosing beliefs based on personal bias.

Or, it could mean that I tailor my surprise to my actual probability of the thing being true, based on the information I have. Heck, I have emotions, I might as well use them. By the way, didn't you notice that you're not surprised all the time? That emotion isn't as irrational as a Straw Vulcan would believe.

I'm not sure what "personal bias" you speak of, but there's no escaping the fact that different people have access to different prior information. They will inevitably make different probability estimates, even if they are perfect Bayesians.

You should read Probability Theory: The Logic of Science. It's an excellent book.

[redhat-reallyp]

> poof magic we have simple mathematical rules on which the universe runs

I'm not arguing against the idea that the universe might be described by simple mathematical rules - after all, we have a fair amount of evidence that it can be, for some value of "simple". But it's an enormous unsupported jump from there to the idea that the mere possibility of such rules somehow gives rise to a universe that follows them, ex nihilo, or variations on that idea.

Generally, such handwaving is not accompanied by much serious exposition. Even Tegmark's writing on the subject doesn't get into it in enough depth to seriously evaluate. It's an amusing conjecture, but I'm not aware of anyone having developed it beyond that point.

It's also strangely reminiscent of other attempts to delegate the creation of the universe to a mysterious unexplained force: is "mathematics did it" really any different than "a god did it" as an explanation? Neither are actually explanations, they just give the superficial appearance of explanation via a sleight of hand in which the entity in question is implicitly assumed to somehow have the necessary wherewithal to do the job it's accused of. To me, "mathematics did it" is about as good an explanation as "the Great Penguin did it".

> Now, assuming our universe does run on math, it is quite impossible to test for different kinds of ontological existence. Do we live in a simulation? If the simulation isn't buggy, we don't stand a chance at root escalation, and we can't tell. Does the mathematical rules exist, like "poof magic", or do they need some exterior force or entity to be actualized? Again, we can't tell, because there's just no way out of our universe.

I agree with this mostly, although again I'll point out that the entire idea of seeing our models of the universe as being somehow responsible for its creation runs the risk of being a huge category error, so I don't take it for granted that the universe actualizes mathematical rules in that sense. The rules we like to model may simply be an occasionally emergent property of a chaotic physical substrate, and we find ourselves in a predictable corner of some randomly organized multiverse by virtue of the anthropic principle.

But to your larger point that it's likely to be impossible to test the ontological status of mathematical rules, that's a major part of why strong claims in this area seem incoherent to me.

> Occam's razor doesn't favour surface simplicity, it favours simplicity at the deepest level.

Occam's Razor is a simple heuristic that has no such bias. The only simplicity it favors is the removal of redundant aspects of a model, and redundancy can exist anywhere, whether superficial or deep. Further, "redundant" can be relative to one's purposes. Many physical models are deliberate simplifications of the phenomena being modeled, e.g. gases, fluid flow. This often seems to be forgotten when people start to confuse mathematical models of the universe with the universe itself.

> By the way, didn't you notice that you're not surprised all the time? That emotion isn't as irrational as a Straw Vulcan would believe.

I distinguish between everyday claims, like someone telling me they went to a movie, and claims about new discoveries about the universe. You don't need to revise your theories about the universe to provisionally accept the claim that someone went to a movie, for example.

But a claim that entails revision of a theory needs to be treated differently, and in that context, being "unsurprising" is not really particularly relevant - such claims can and should be evaluated on the basis of whether they are supported sufficiently strongly.

> Heck, I have emotions, I might as well use them.

I disagree with using them to justify a conclusion about the validity of a scientific claim. Certainly many people seem to operate on this basis, but it leads to a great deal of irrational behavior.

> You should read Probability Theory: The Logic of Science. It's an excellent book.

Thanks, I'll check it out.

[gaze]

Things that work on simple models motivate work on more complex models. He STARTS OUT by saying N=4 SYM is a toy model. The klein-gordon equation is unphysical but motivated a lot of good physics.

[selimthegrim]

In condensed-matter physics, toy models play with you!

http://arxiv.org/abs/cond-mat/0007254

[redhat-reallyp]

I'm not questioning whether the work has value, but the article is hyping it way beyond justification.

[gruseom]

What you're saying makes it sound comparable to a compelling software demo that only works on simplified test cases.

[Panoramix]

Sort of, except in that analogy people like Dijkstra and Knuth are saying "this is a big deal, let's take a closer look".

[bsullivan01]

what are your qualifications? No offense meant, but I am trying to see if this is real or not.

Quite a few smart people seem excited by it, yet you dismiss it

[shadowmint]

I think the point here is don't hold your breath.

Science like this has to be slow and careful. Sudden magical breakthroughs are vanishingly rare, and this probably isn't one; but it is interesting, and worth getting excited about.

.. just don't go throwing your Standard Model quite yet. :)

[bdg]

> your Standard Model

If you don't understand your standard model, it's merely a standard belief.

If you understand it, it can be invalidated and thrown away by the 'magical breakthrough' if it provides evidence.

These things shouldn't be treated as a question of political buy-in into to the model.

[redhat-reallyp]

"Quite a few smart people seem excited by it"

Why aren't you asking them for their qualifications, then? Serious question, think about what your choice implies. Is it that "you want to believe", perhaps?

You don't need a PhD in quantum physics to detect the hype in this article. The comment I responded to was reacting more to the unsupported claims and hype than any actual discovery.

"yet you dismiss it"

I'm not dismissing that the work could have value, but the article makes claims that go far beyond anything that's been demonstrated.

[vinceguidry]

In other words you just spent a dozen or so paragraphs venting your bullshit detector in a space where numerous contributors that are much, much smarter than you have indicated otherwise.

It's like inverse bike shedding.

[redhat-reallyp]

Perhaps you missed the part of my very short comment where I wrote "I'm not dismissing that the work could have value, but the article makes claims that go far beyond anything that's been demonstrated."

You might want to re-read my original comment and take note of the issues I commented on. If you disagree with what I'm saying, why not respond on those points? I can't help wonder if your problem is actually that I'm interfering with your "I want to believe" circuitry.

I like to distinguish between actual science and mathematics and nonsensical metaphysical claims like "...giving up space and time as fundamental constituents of nature and figuring out how the Big Bang and cosmological evolution of the universe arose out of pure geometry." YMMV.

[vinceguidry]

There's reasoned discussion of possible philosophical implications of the recent findings and then there's your post.

[redhat-reallyp]

At https://news.ycombinator.com/item?id=6406551 I'm having a reasoned discussion with someone who responded more substantively to what I wrote. Your petty sniping is not reasoned discussion.

[bsullivan01]

Why aren't you asking them for their qualifications, then?

Don't need to, checked them as they posted their names and all their research is online. http://arxiv.org/abs/1212.5605

They also posted the math behind it (which went over my head) unlike you. Next time, if you want to be taken seriously explain yourself better and try to be specific. If you know what you are talking about, of course.

[redhat-reallyp]

You're comparing me to the authors of the work? My misunderstanding then, I thought you were comparing my take to that of other commenters.

"try to be specific"

I did post specifics, include a link to an example of the issues with supersymmetry as a physical model.

"explain yourself better"

If you can identify what you didn't understand, I'd be happy to explain it further. I stand by my comment - it doesn't contain anything non-factual that can't be supported with references, although when it comes to silly metaphysical claims about the universe arising from pure geometry, those references are going to be to philosophy texts, not science texts. Which hints at the problem with the claim in the first place.