Has Physics Gotten Something Really Important Really Wrong? (npr.org)

Slashdot reader schwit1 quotes an article from NPR: Some researchers now see popular ideas like string theory and the multiverse as highly suspect. These physicists feel our study of the cosmos has been taken too far from what data can constrain with the extra "hidden" dimensions of string theory and the unobservable other universes of the multiverse... it all adds up to muddied waters and something some researchers see as a "crisis in physics."
The article quotes Roberto Mangabeira Unger and Lee Smolin, the authors of a new book arguing that "Science is corrupted when it abandons the discipline of empirical validation or dis-confirmation. It is also weakened when it mistakes its assumptions for facts and its ready-made philosophy for the way things are." And according to this analysis of the book, what they're proposing is "to take a giant philosophical step back and see if a new and more promising direction can be found. For the two thinkers, such a new direction can be spelled out in three bold claims about the world. There is only one universe. Time is real. Mathematics is selectively real."

Comments

History repeats itself

[Anonymous Coward]

There was a time when humanity believed that everything could be explained by mechanics.
Higgs was ridiculed for good 50 years.This is no different.
String theory evolved great deal from where it was first formulated, thins that were not good are already invalidated.
There is no crisis of physics here, jut a massive layer of incomplete work.

Few points to add.
"There is only one universe" - sounds like theological clam. And just as unconfirmed ad multiverses.
"Time is real" - Einstein might disagree. Time is the imaginary part in the complex equations of space-time.
"Math is selectively real" - Only f the reality is defined by the capabilities of our brains and our technologies,

Re:History repeats itself

[Anonymous Coward]

"There is only one universe" - sounds like theological clam. And just as unconfirmed ad multiverses.

Consider two competing hypothesis: "there is an elephant in the corner of the room but it is undetectable" versus "there is no elephant in the room". Both predict the same outcome, but most would say the latter is the simpler explanation even though on a technical level this choice is arbitrary. Now replace the word elephant with parallel universe. Until we come up with an experiment that makes a testable prediction on the basis of there being multiple universes that does not have a simpler explanation *not* involving multiple universes it seems entirely reasonable to assert that there is only one universe.

"Time is real" - Einstein might disagree. Time is the imaginary part in the complex equations of space-time.

In some formulations of relativity time is treated as an imaginary number. In others space is treated as an imaginary number. In most both time and space are treated as real numbers and the signature of the metric tensor is assumed to be either + - - - or - + + +. All of these are isomorphic, and the choice is down to personal aesthetics (or whatever choice the book/paper you are reading decides to use). Nothing in any of this implies that time is "unreal" in either an arbitrary mathematical sense or any other sense.

"Math is selectively real" - Only f the reality is defined by the capabilities of our brains and our technologies,

I'm with you on this point. Mathematics is the formal expression of a set of axioms. We are free to choose these axioms. Assuming the universe does not randomly change its axioms periodically (and the choice does not itself obey a set of meta-axioms, for want of a better word) then yes, maths is real (which is of course not the same as saying that our current chosen set of axioms coincides with those of reality).

Looking at the wrong branch of physics to trash

[fadethepolice]

The article mentions hidden dimensions and other universes in the same sentence. This is a pet peeve of mine. In Multi-dimensional quantum mechanics the dimensions are additional directions. They are not other universes and the combination of the two in one sentence is either intentinally muddying the water, or the person writing the article is not familiar with the mathematics involved and should not be taken seriously. The standard Cartesian coordinate system used to describe our universe in it's basic sense contains x.y, and z, directions, a set of values that many of the programmers on Slashdot are familiar with. Multi-dimensional physics just adds more of these in an attempt to explain the very real observable quantum effects that Newtonian physics and relativity cannot explain and never will. We currently know more about the Andromeda galaxy than the Milky Way because it is difficult to describe an object when you are inside it. Getting a third person look at the universe, even if it is just a mathematical trick, is probably the easiest way to describe it. The refusal to do so is probably not going to go very far. What the emergence of time means is also not what they are describing it to be and should not be looked upon as a valid argument. In a holographic quantum view of the universe it could be considered similar to a wave propagating through a substrate, but also be akin to a temporary chemical reaction wave, where the structure of the substrate is momentarily changed while the wave propagates through. This temporary excitation of the substrate generates the universe we live in. The movement of the universe's propagation is in the direction of time. My take on the hidden dimensions is that instead of viewing them as hidden, we should look at them as directions in which the particles we are made of have a zero width. The reason we cannot travel in time is not because the directions don't exist, it's because the particles we are made of have a zero width in that direction. We would have to be made of something else, and when we went backwards in time we would effect leave our current universe. Other particles, such as the elemental particle of gravity have a non-zero width in one of these direction. What we should really be talking about is the fact that relativity CANNOT describe the orbital trajectories of any stars accurately. The lack of a theory to accurately explain a basic observable fact is more problematic than the inability of technology to currently test the most advanced physics problems. Once our ability to manipulate quantum effects (such as the creation of a working quantum super computer - looking at you google) and we can create technology that is based on quantum mechanics then maybe we will be able to test the theories. Second failure of current theory that I don't think is spoken of enough is the failure of the planck observatory to detect the effects of gravitational waves on the cosmic microwave background. There were several stories about the waves being detected but second looks at the data supporting this cast serious doubt. Since we have now confirmed the existence of gravitational waves and their effects have not been observed as inflation predicts, then the current theory of the big bang they reference at the beginning of the article (we can describe the universe up to a bit before it's creation) is in fact not supported by current experiments and should be rethought. Instead of taking a step back from quantum mechanics we need to take a second look at the non quantum component of physics as it is currently not supported by current data.

Re:old wisdom

[Rei]

There's unfortunately a common attitude in the physics world that anything that the math allows - anything that you can't rule out - is real. Beyond this, I think the discovery of things like general relativity and quantum physics got us so used to the concept that the universe is wierd that there's few possibilities that come across as "too weird to be real".

On the other hand, it's sort of like saying, "we know little of the fish that live in the deep oceans, and we've seen fish that come in all sorts of forms.... since I can't rule out that there's a fish down there that looks exactly like Justin Bieber, then there must be one". The ability to deduce the existence of something based on what you can't rule out requires that you can be certain that your model is perfectly describing everything about the dataset that it's supposed to be modeling. But we know that they're not describing everything about the universe. We know that there's things that they specifically don't model.

Re:But Seriously...

[tlhIngan]

We have to recall the Quantum mechanics was a radical explanation for a real problem. Theory says that if you put a heat source in a black box the universe should be destroyed. This does not happen so the theory was wrong and we ended up with a theory was very difficult to prove. I have had professors tell me that the absolute proof of quantum mechanics, i.e. an experiment that could not be explained using an alternative theory, did not exist until the 1960's when lasers were used. That does not mean that an alternative theory will win out, but there is a great deal of support for QM.

The other thing with quantum mechanics is we use it everyday, and we still don't know how it works. LEDs, flash memory and many other technologies we use today all apply quantum mechanical principles in order to work.

I suppose that's where the conflict lies - we assume a traditional model - science makes a discovery, engineers apply it to create technology. Unfortunately, these days it's a blended set - engineers may discover something and then ask science to explain it while they figure out how to exploit the something.

And understanding why is key - if we properly understood how LEDs work, we can make brighter, more efficient LEDs that last longer, and exploit that to create better say, OLED panels or even matrix LED panels (LEDs are relatively big, which is why we generally go OLED, but if we can improve thengs, maybe we can avoid using OLED and just have our screens made up of LEDs). Or flash memory that's denser and lasts longer (the buried or floating gate gets its charge put on and taken off by electron tunnelling, but we only have crude control over it - so electrons are left during erasure, and we damage the insulation during programming/erasure which leads to charges leaking off and limited life).

There's plenty of stuff where we know how to exploit QM to do what we want, but we can certainly do better. We know the how, but not the why

Absence of evidence

[Kim0]

And what IS the evidence then for there being only one universe?
Same goes for time being real.
The article does not provide evidence for this, thus contradicting its own demand for evidence.

It is just bla bla blah.

Re:old wisdom

[silentcoder]

The good physicists say "This fits the math - so it's possible, let's see if we can make useful predictions from it and see where it leads". The trouble with assuming absurd possibilities cannot be true is that they all too often end up being true. The most obvious example in physics is Galileo - whose idea of the sun being the center of the solar system was deemed quite absurd by the orthodoxy of his time - yet turned out to be true.

But even in the modern age we've seen that happen repeatedly - notably with your example of the ocean. We found ceolacanth fossils since the 19th century and were aware that some 230 million years ago a fish like this existed. It was always POSSIBLE they still survived and had just avoided detection all this time - but nobody really thought it was likely, and indeed if you stated that possibility to scientists you would have been laughed at... until we found some living specimens and suddenly it was true.
Another example is the giant squid. We've had tales of them dating back at least 3000 years. And science rejected their existence as myths pretty much from the birth of naturalism as a field of science (the precursor to biology). Just another ridiculous myth of ancient people. Over the centuries evidence kept building up - which kept the conspiracy theories going, most notably whales caught with wounds that appeared to come from massive suckered-arms. But scientists wouldn't buy the possibility - and came up with any number of 'more plausible' explanations for the evidence before them.

They didn't get serious about the possibility of the giant squid until the 1850s when portions of one that had been stranded arrived in France. Today we know that not only does the giant squid exist - it's not even the largest squid around. The Colossal Squid is even bigger (we don't know which one Aristotle had written about - only that he didn't know there were two, since he specifically wrote about one gigantic squid much bigger than the common ones).

So we should at least consider the possibility that the Justin Bieber fish does in fact, exist. The biggest evidence for it's existence is that apparently they can breath air and one of them is currently a multi-platinum recording artist, based on the recordings from that specimen I would advance the conjecture that their air-breathing is limited and in an early stage of evolution (pre-booklung even) - more akin to a catfish crossing between ponds than a lungfish.