5 ms·

He’s also throwing some fun shade in other interviews towards physicists that are obsessing over theories designed to be unprovable (multiverse, string theory,

by lithos 6y ago

He’s also throwing some fun shade in other interviews towards physicists that are obsessing over theories designed to be unprovable (multiverse, string theory, and similar). But are then utterly against something like his theory, even if it’s left in statistical form (IE: based on our current understanding, this object is x% likely to be unnatural). (Not in this article though)

XorNot 6y ago
> designed to be unprovable (multiverse, string theory, and similar) None of those are "designed" to be unprovable, and many make predictions, they just don't currently make predictions within the measurement capabilities of existing instruments or near-future instruments. Work on them is specifically oriented towards trying to find achievable measurements that they can uniquely predict the results of. They also don't have more mundane secondary explanations ("it looks like a rock and is a rock") because in most cases there just isn't one.
- macspoofing 6y ago
  >None of those are "designed" to be unprovable, and many make predictions, they just don't currently make predictions within the measurement capabilities of existing instruments or near-future instruments. It's worse than that. The obvious and natural theoretical predictions have already been ruled out by experimental discoveries like a positive cosmological constant, and lack of discovery of super-symmetric particles at the LHC. But those theories tend to be infinitely fine-tunable, so you can always find a way to make them 'fit' whatever you want. Also, I'm not sure if there is ANY experimental guidance that suggests something like string theory is actually worth pursuing as a description of reality ... but I hear the math beautiful.
  - pa7x1 6y ago
    All physical theories are fine-tuneable to some extent. The Standard Model of physics, our best tested theory, has 25 physical constants that need be put by hand. That doesn't make the theory able to predict "whatever you want". It means that you have to perform at least 25 independent physical experiments to fix those free parameters and then your theory is set and can be used to make predictions. The reason theoretical physicist pay attention to String Theory is because it's the only consistent theory of Quantum Gravity we know of. That doesn't make it the correct one for our universe, but is the only one that we know. And since physicist have been trying to crack the problem for almost 100 years now, it makes sense that some attention is paid to it, at least in the hopes that we learn how to build other theories of Quantum Gravity.
    - BlueTemplar 6y ago
      Hmm, what happened to Loop Quantum Gravity?
      - pa7x1 6y ago
        Disclaimer: I have no horse in this race, I studied Theoretical Physics but left academia for the industry many years ago. My bills won't be paid whatever side of the discussion gets funded. 1. In its canonical formulation we don't know if Loop Quantum Gravity produces the right classical limit (i.e. General Relativity). In its spin-foam formulation we can get the right classical limit but we don't know if the formulation is mathematically consistent. 2. The semi-classical results that LQG obtains, namely Black Hole entropy, is very suspect. The semi-classical result is pretty much cooked in (at least it was years ago when I was studying these things, maybe they have refined the way the calculate it recently) and the logarithmic quantum corrections are wrong (see: https://arxiv.org/pdf/1205.0971.pdf https://arxiv.org/pdf/1205.0971.pdf). 3. Furthermore, it's questionable how can you come up with a consistent theory of pure-Quantum Gravity that doesn't include all other forces and matter since gravity interacts with everything (that is its most defining characteristic) and in Quantum Mechanics you must include everything that can happen otherwise the diagrams would need to conspire in very peculiar ways to produce consistent results. 4. There are also technical arguments to be made regarding the mathematical construction of the theory: https://physics.stackexchange.com/questions/67211/why-is-standard-model-loop-quantum-gravity-usually-not-listed-as-a-theory-of-e/360010#360010 https://physics.stackexchange.com/questions/67211/why-is-sta... TL;DR: The viability of LQG as theory of Quantum Gravity has always been overstated to the general public. By the classical journalistic trick of giving equal voice to the two sides of the discussion; the reader, with not much else to judge by, has to assume equal plausibility for both sides of the argument. With a bit more careful inspection you would notice that the number of experts paying attention to one side or the other is radically different. So either the entire High-Energy physics community has fallen in some collective delirium and "big physics" conspires to suppress LQG or maybe LQG doesn't deserve as much attention as the general public has been led to believe.
    - macspoofing 6y ago
      Like you said, people take the Standard Model seriously not because they like it (in fact, there is a level of embarrassment that physicists seem to have on this because the theory is so ugly), but because it has been experimentally verified within its regime. The fine-tuned constants have been experimentally derived. So you're right, fine-tuning by itself is not necessarily a problem ... if it's experimentally tested. If you don't have experimental guidance, what else is left? At that point, you're a mathematician working in abstract worlds. >The reason theoretical physicist pay attention to String Theory is because it's the only consistent theory of Quantum Gravity we know o Another String Theory wart ... the theory fits more naturally in a universe with a negative cosmological constant - which is not our universe. To be clear, I'm not making an argument that String Theory should be abandoned. I'm not physicist or a mathematician so I don't have the expertise to make that kind of judgement, although there are credible physicists who do make this argument. But at at least part of the popularity of String Theory entails an interesting socio-cultural phenomena that should be studied and analyzed by philosophers of science.

by lithos 6y ago

XorNot 6y ago

> designed to be unprovable (multiverse, string theory, and similar) None of those are "designed" to be unprovable, and many make predictions, they just don't currently make predictions within the measurement capabilities of existing instruments or near-future instruments. Work on them is specifically oriented towards trying to find achievable measurements that they can uniquely predict the results of. They also don't have more mundane secondary explanations ("it looks like a rock and is a rock") because in most cases there just isn't one.

macspoofing 6y ago
>None of those are "designed" to be unprovable, and many make predictions, they just don't currently make predictions within the measurement capabilities of existing instruments or near-future instruments. It's worse than that. The obvious and natural theoretical predictions have already been ruled out by experimental discoveries like a positive cosmological constant, and lack of discovery of super-symmetric particles at the LHC. But those theories tend to be infinitely fine-tunable, so you can always find a way to make them 'fit' whatever you want. Also, I'm not sure if there is ANY experimental guidance that suggests something like string theory is actually worth pursuing as a description of reality ... but I hear the math beautiful.
- pa7x1 6y ago
  All physical theories are fine-tuneable to some extent. The Standard Model of physics, our best tested theory, has 25 physical constants that need be put by hand. That doesn't make the theory able to predict "whatever you want". It means that you have to perform at least 25 independent physical experiments to fix those free parameters and then your theory is set and can be used to make predictions. The reason theoretical physicist pay attention to String Theory is because it's the only consistent theory of Quantum Gravity we know of. That doesn't make it the correct one for our universe, but is the only one that we know. And since physicist have been trying to crack the problem for almost 100 years now, it makes sense that some attention is paid to it, at least in the hopes that we learn how to build other theories of Quantum Gravity.
  - BlueTemplar 6y ago
    Hmm, what happened to Loop Quantum Gravity?
    - pa7x1 6y ago
      Disclaimer: I have no horse in this race, I studied Theoretical Physics but left academia for the industry many years ago. My bills won't be paid whatever side of the discussion gets funded. 1. In its canonical formulation we don't know if Loop Quantum Gravity produces the right classical limit (i.e. General Relativity). In its spin-foam formulation we can get the right classical limit but we don't know if the formulation is mathematically consistent. 2. The semi-classical results that LQG obtains, namely Black Hole entropy, is very suspect. The semi-classical result is pretty much cooked in (at least it was years ago when I was studying these things, maybe they have refined the way the calculate it recently) and the logarithmic quantum corrections are wrong (see: https://arxiv.org/pdf/1205.0971.pdf https://arxiv.org/pdf/1205.0971.pdf). 3. Furthermore, it's questionable how can you come up with a consistent theory of pure-Quantum Gravity that doesn't include all other forces and matter since gravity interacts with everything (that is its most defining characteristic) and in Quantum Mechanics you must include everything that can happen otherwise the diagrams would need to conspire in very peculiar ways to produce consistent results. 4. There are also technical arguments to be made regarding the mathematical construction of the theory: https://physics.stackexchange.com/questions/67211/why-is-standard-model-loop-quantum-gravity-usually-not-listed-as-a-theory-of-e/360010#360010 https://physics.stackexchange.com/questions/67211/why-is-sta... TL;DR: The viability of LQG as theory of Quantum Gravity has always been overstated to the general public. By the classical journalistic trick of giving equal voice to the two sides of the discussion; the reader, with not much else to judge by, has to assume equal plausibility for both sides of the argument. With a bit more careful inspection you would notice that the number of experts paying attention to one side or the other is radically different. So either the entire High-Energy physics community has fallen in some collective delirium and "big physics" conspires to suppress LQG or maybe LQG doesn't deserve as much attention as the general public has been led to believe.
  - macspoofing 6y ago
    Like you said, people take the Standard Model seriously not because they like it (in fact, there is a level of embarrassment that physicists seem to have on this because the theory is so ugly), but because it has been experimentally verified within its regime. The fine-tuned constants have been experimentally derived. So you're right, fine-tuning by itself is not necessarily a problem ... if it's experimentally tested. If you don't have experimental guidance, what else is left? At that point, you're a mathematician working in abstract worlds. >The reason theoretical physicist pay attention to String Theory is because it's the only consistent theory of Quantum Gravity we know o Another String Theory wart ... the theory fits more naturally in a universe with a negative cosmological constant - which is not our universe. To be clear, I'm not making an argument that String Theory should be abandoned. I'm not physicist or a mathematician so I don't have the expertise to make that kind of judgement, although there are credible physicists who do make this argument. But at at least part of the popularity of String Theory entails an interesting socio-cultural phenomena that should be studied and analyzed by philosophers of science.