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Hawking: No 'Theory of Everything'
Flash Modin writes "In a Scientific American essay based on their new book A Grand Design, Stephen Hawking and Leonard Mlodinow are now claiming physicists may never find a theory of everything. Instead, they propose a 'family of interconnected theories' might emerge, with each describing a certain reality under specific conditions. The claim is a reversal for Hawking, who claimed in 1980 that there would be a unified theory by the turn of the century."
xkcd
"The claim is a reversal for Hawking, who claimed in 1980 that there would be a unified theory by the turn of the century."
I think the turn of the century reversed his claim for him.
He's a theoretical physicist. Theories ARE his results.
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I'm reminded of a scene from DS9. Sure it's fiction, but it always held some sway with me:
Bashir: "Trevean was right. There is no cure. The Dominion made sure of that. But I was so arrogant, I thought I could find one in a week!"
Jadzia: "Maybe it was arrogant to think that. But it's even more arrogant to think there isn't a cure just because you couldn't find it."
Hawking a smart guy, but he by no means knows everything. Throwing in the towel and declaring that there is no right answer simply because he hasn't found it just doesn't hold much water with me. We might not figure it out for 100 years. We might figure it out tomorrow. We might NEVER figure it out, but simple logic says that there is a unified equation. It might not be simple or pretty, but if the universe operates on a consistent set of physical laws, it's out there.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
Godel used the term "formal system" to specifically mean a recursive axiomatic system that can do arithmetic. I don't think it really applies here.
I don't actually mind if this is the case. What it means then, is that new properties of aggregated matter emerge as you go up, and up in scope and scale, and that there does not have to be a set relationship on what rules must emerge.
Other than aesthetics, those emergent rules don't have to carry a thread of logic visible at all scopes. Rather, you just need to have the large number of interactions actually occur in relationship to eachother to see the combined effect, with many aspects unforeseeable by only observing the elements many magnitudes smaller.
Whether this might make the universe a more or less beautiful puzzle to figure out is open to interpretation.
Ryan Fenton
It seems like he's been saying stuff recently just to say stuff.
Totally. He just likes to hear his own voice.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
I'm right here. I promise I do exist. Really.
As scientists age they become somewhat jaded, it happens to a lot of people. Hawking has seen a problem he thought was about to be solved get ever more complex while little new progress has been made. I don't blame him for changing his stance. I had a professor during my undergrad who had been a part of some of the first fusion research, and he would occasionally bring up that he didn't think it was possible. According to him, "the kids today are trying what we tried and couldn't get to work back then" (Paraphrased). Maybe doubting there is a solution to the problems you have struggled with all your life is the best way to find peace as your life winds down?
Oh, on a personal opinion note, I doubt we will ever find a *provable* theory of everything. Eventually someone will put together something that relates a lot of complex fields, but I suspect it will be something ad hoc and beyond the practical limits of humanity to test. (*cough* string theory variant *cough*)
Now you're making me wish that I hadn't commented in this discussion just so I could mod you up. Although if I had never commented, then you wouldn't have been able to reply to me and I wouldn't have been able to mod you up anyway. Maybe some smart scientist could help us out with this paradox.
We always knew Comcast was corrupt, here's the proof: http://tech.slashdot.org/comments.pl?sid=1909890&cid=34545432
It happens. James Watson, who was part of the team that discovered the structure of DNA, has been saying crazier things for years.
My favorite was his presentation on why men liked butts. Certainly funnier than his comments on race.
Scientists sometimes don't age well. We probably age better on average than rock stars, but then again people pay don't take what rock stars say as seriously as scientists.
We work on the assumption that the laws of physics are perfect and complete, and we are just trying to reveal them. The laws of physics could work well enough but actually be incomplete and consistent as you point out. They could even bebe crappy, bloated and buggy with lots of missing chunks, unused bloat and even errors.
... these worked well enough, but were ultimately wrong, the truth was more complex and nuanced, but now we're finding the universe is fuzzy, clumsy and possibly buggy (inflation, possible variations in c, other weirdness).
If the laws of physics emerged naturally, for example budding off from a parent universe, and subject to a process of evolution I would expect theories of everything to be 'just good enough' and barely work rather than somehow perfect and elegant and mystical. Much like the junk DNA, apendix and mens nipples that rides along with us because evolution didn't really have pressure need to get rid of them.
I would say we should by default expect a theory of everything a whole basket of seemingly clumsy unweildy theories that barely fit together - after all they only need to be just good enough for us to be here and not any better. If we expect flawless elegant unified symmetry and beauty, then we'd need to demonstrate why (without invoking God to explain etc).
Researchers have been seduced by subjectively elegant and simple equations all the way back to F=MA
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Instead, they propose a "family of interconnected theories" might emerge
Which, if you read them all at the same sitting and follow all the connections, just might read like one big...unified theory.
This seems very, very close to a distinction without a difference.
No, there is a very important difference. Hawking is stating that there may be "locally everywhere solutions" without a "global solution." This is a very important concept in advanced mathematics. Go read about the mathematical terms "sheaf" and "local-global principle."
Hawking is essentially saying that there very well may not be one single theory which explains everything. Instead, there may be a bunch of theories, each of which is valid only in certain areas, and which agree with one another where they overlap, even without a global solution.
For a simple example which many readers may already be familiar with, consider the complex logarithm (e.g. the natural log on the complex numbers). To make it well defined, you must make a "branch cut" and decide which branch you want to take. Different branches agree where they overlap, but there is no single global solutions... just a patchwork of solutions that agree where needed (blah, blah lift to a covering space). Pick up a book on complex analysis for details.
Just invent a one-way time machine. Then you could mate with all the women you wanted when men become scarce (after the giraffes have long since ceased to rule the planet) then move forward in time, wait for the last photon to decay, see the Big Bang take place, take a potshot at Hitler and as the current time approaches, slow down enough to see the comments appearing, wait for someone else to make the joke then mod them up!
Of course you have to hope this universe isn't 10' higher than the previous universe.
We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
...Theory of Everything held a press conference today, stating "There is no Stephen Hawking."
When asked what the implications were as to whether or not there could ever be a Stephen Hawking, ToE replied "The door is open for a Stephen Hawking in the future, but it can only be a possibility if graphene birds fly out of my lily white butt..."
I mean, it wouldn't it be surprising if they were given advanced degrees like "Doctor of Philosophy" or something like that?
Faster! Faster! Faster would be better!
But, Hawking is past his prime.
He's only ten years older than me, kid. He's a physicist, not a football player. Unless you get alzheimer's or drink a lot or play high impact sports (boxing or non-US football) your brain doesn't suffer much if any.
Like one of my old college profs was fond of saying, "kid, I've forgotten more than you've ever learned".
However, after his comments on active SETI being dangerous
I agree with him about that. Actively hunting for species that make us look like chimpanzes by comparison doesn't seem like the smartest thing we can do.
coaching a crappy minor league team
I'd say that research at Cambrige is hardly equivalent to coaching a crappy minor league team. And the list of his accomplishments puts your "past his prime" into perspective (see the wikipedia article on him):
1975 Eddington Medal
1976 Hughes Medal of the Royal Society
1979 Albert Einstein Medal
1981 Franklin Medal
1982 Order of the British Empire (Commander)
1985 Gold Medal of the Royal Astronomical Society
1986 Member of the Pontifical Academy of Sciences
1988 Wolf Prize in Physics
1989 Prince of Asturias Awards in Concord
1989 Companion of Honour
1999 Julius Edgar Lilienfeld Prize of the American Physical Society[45]
2003 Michelson Morley Award of Case Western Reserve University
2006 Copley Medal of the Royal Society[46]
2008 Fonseca Price of the University of Santiago de Compostela[47]
2009 Presidential Medal of Freedom, the highest civilian honour in the United States[4]
"When I hear of Schrödinger's cat, I reach for my pistol." -- Stephen Hawking
I think I'll change my sig...
Free Martian Whores!
You're conflating blings with accomplishment. Should have listed his papers instead of awards given to him.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
I've been watching documentaries about Dr Sheldon Cooper's work out at Caltech and I'm lead to believe that he's very close to proving String Theory as a Grand Unified Theory.
Surely, Professor Hawking is aware of this research?
"Karma can only be portioned out by the cosmos." -- Homer Simpson
Because you don't understand Godel's theorem, which is grossly misunderstood by basically everyone who's ever heard of it colloquially. Here, have a little read on how it's so wonderfully misunderstood, and so horribly misapplied.
Prove it.
Easy. Proof by contradiction:
Assume there is a universal (and extremely long) string U that encodes a countable set containing all problems P_i (encoded as decision problems) that are possible in this Universe. We can trivially see that indeed U must contain all problems that exist for it to represent the Universe. Otherwise, it does not represent the Universe.
Furthermore, if every decision problem P_i in U is decidable, then there is a (not necessarily unique) Turing Machine T_i that halts in finite time for each problem P_i in U. With this assumption, then there would be a Universal Turing Machine T that is a chain of all turning machines T_i that can compute (and thus give meaning) to all problems P_i in U (the string encoding of the universe.) That is, T is the universe.
But the halting problem is not in U. In fact, U cannot contain neither semi decidable nor undecidable problems (which was our base assumption). However, the halting problem (and all other semi-decidable and undecidable problems) exists in the Universe. U then, cannot be an encoding of the universe, and T (a turing machine) cannot be the Universe either.
qed.
It may just be a matter of scale - we simply aren't able to take a large enough view. A turing machine, if you only look at one small part of it, is no longer turing-complete. And the presence of a turing-complete machine doesn't mean the enclosing reality suddenly is turing-complete. Think babushka dolls, as in Soviet Russia, Turing completes YOU!
Dude, the fact that there are problems in this Universe (and thus part of it) that are not turing computable (a mathematical fact indeed) does indicate that the universe is not a Turing complete nor Turing computable. The universe is naturally uncountable.
I don't know Godel as well as some other people here, but I do know physics and you're making a lot of assumptions there, starting with that the universe can be "derived" from a theory of everything. The name is a little unfortunate, but the goal of a theory of everything is to create a unified description of the fundamental forces, not a program to simulate the entire universe. If you wanted to simply say "the theory of everything won't be able to tell you absolutely everything about every particle in the universe," you'd be right, and probably that's where you're going with your incompleteness thing.
More fundamentally though, you're assuming the universe is a logical system. From a physicists point of view, it is a happy coincidence that rigorous mathematics is useful in describing the universe, but there is nothing that demands that this is the case (more practically: we're happy in physics to have assumptions about things like causality and time invariance, where needed).
This may sound crazy to most people, but why exactly mathematics has been so successful in physics is still a subject of debate among physicists: whether mathematics approximates an ultimately imperfect physical reality or mathematics *is* physical reality. I don't think it will be settled soon.
However, the halting problem (and all other semi-decidable and undecidable problems) exists in the Universe.
This is a HUGE assumption on which your entire argument hinges, so I think you need to define it more precisely, and provide some evidence that it is true.
Your argument seems to fall apart due to equivocation -- at the beginning you define a set of "problems" that the universe turing machine has to solve. For example, one of those "problems" might be "if you arrange mass in a certain configuration, in which direction will it accelerate?"
However, you then include "the halting problem" in this set. Bzzzt, full stop. This is a decidedly different sense of the word "problem." In this case, we're talking about an abstract idea that only exists as definitions on paper and in peoples' minds, but doesn't actually physically exist in the universe. In other words, our universe can talk about and consider and represent undecidable problems, but that doesn't mean it can actually solve them.
If you disagree, please describe a phyisical system that is "the halting problem" or some other undecidable problem and show that the universe can indeed resolve it.
The following sentence is true. The preceding sentence was false.