5 ms·

Quantum Suicide

6 points by sabhishek 19y ago

mxh 19y ago
Does the Copenhagen Interpretation strike anyone else as eerily like lazy evaluation? My other thought is that once you're doing 'thought experiments', you've become rather unmoored from science as I understand it: Observation, Hypothesis, Prediction, Experiment, and so forth. Hopefully, the 'thought experiments' will lead to something testable.
- rms 19y ago
  Thought experiments can reveal profound results beyond what current instruments are capable of measuring. In 1935, Einstein and friends published a thought experiment that basically said "Well if all this quantum theory is true, then locality can't possibly be a principle." It turns out that locality isn't actually a principle of physics and now we have entanglement, Einstein's "spooky action at a distance."
  - mxh 19y ago
    To the extent that thought experiments suggest real experiments, they are indeed valuable. I disagree that they can 'reveal ... results', however. For instance, Einstein's thought experiment was designed to 'prove' that QM was wrong. Obviously, that result was incorrect.
curi 19y ago
They have no clue what they are talking about. For example this: This is the same case with quantum suicide. When the man pulls the trigger, there are two possible outcomes: the gun either fires or it doesn't. In this case, the man either lives or he dies. Each time the trigger is pulled, the universe splits to accommodate each possible outcome Universes do not split like that. That would mean many universes were being created from nothing every instant. What actually happens is there are already infinitely many "universes" and they become different. And not one per outcome, but in proportion to the probability of outcomes.
- angryprofessor 19y ago
  >Universes do not split like that. That would mean many universes were being created from nothing every instant. What actually happens is there are already infinitely many "universes" and they become different. And not one per outcome, but in proportion to the probability of outcomes. It's not the writers of the article who have no clue. It's quantum physicists themselves. In the Copenhagen interpretation of QM, a conscious observer induces wave collapse (a random process). In this interpretation, there are no other worlds. In Wave Collapse/Many Worlds, a parallel universe is created in which wave collapse occured but gave a different outcome. There are different interpretations of QM (e.g. bohmian mechanics or GRW/stochastic collapse) which don't have this problem. If you are interested in QM, I strongly suggest looking these theories up. But Copenhagen QM (the theory in most textbooks) does have this problem. The reporter did an adequate job of explaining the consensus view. The problem is really that the consensus view can allow for nonsense such as what was described in the article.
  - pfedor 19y ago
    "There are different interpretations of QM (e.g. bohmian mechanics or GRW/stochastic collapse) which don't have this problem. If you are interested in QM, I strongly suggest looking these theories up." I respectfully disagree. You can spend years reading about interpretations and the gain in terms of your understanding of Quantum Mechanics will be zero. For anyone interested in Quantum Mechanics, I strongly suggest actually trying to learn it, instead of dabbling into confusing popular articles the authors of the majority of which have never studied theoretical physics themselves. Please note I'm not saying that you don't know Quantum Mechanics. I just think your advice is bad. So here's my advice to anyone out there who feels that they want to know more. See the Schroedinger equation. Learn how to calculate energy levels for the harmonic oscillator and for the hydrogen atom. Read first six chapter's of Paul Dirac's "The principles of quantum mechanics". The time spent reading about interpretations and philosophical implications of QM is wasted. People who do research in theoretical physics devote very little time to such considerations, or no at all.
  - curi 19y ago
    In Wave Collapse/Many Worlds, a parallel universe is created in which wave collapse occured but gave a different outcome. That is incorrect. Many Worlds does not say universes are created all the time, it says they already exist and become differentiated. BTW all the other interpretations are ridiculous attempts to avoid facing counter-intuitive facts. See, for example, David Deutsch's speech at the recent Everett conference http://www.philosophy.ox.ac.uk/misc/everett/Deutsch%20-%20Apart.wmv http://www.philosophy.ox.ac.uk/misc/everett/Deutsch%20-%20Ap...
joeguilmette 19y ago
haha quantum physics may as well be chinese to me. the only explanation that has ever made the least bit of sense is that cartoon with the old man super hero talking about light particles.
majimojo 19y ago
Nice movie plot for Jet Li perhaps, but they don't actually explain how to kill yourself in all universes. So, unless you're a cat or Solid Snake, you can get out of that box now.

6 points by sabhishek 19y ago

mxh 19y ago

Does the Copenhagen Interpretation strike anyone else as eerily like lazy evaluation? My other thought is that once you're doing 'thought experiments', you've become rather unmoored from science as I understand it: Observation, Hypothesis, Prediction, Experiment, and so forth. Hopefully, the 'thought experiments' will lead to something testable.

rms 19y ago
Thought experiments can reveal profound results beyond what current instruments are capable of measuring. In 1935, Einstein and friends published a thought experiment that basically said "Well if all this quantum theory is true, then locality can't possibly be a principle." It turns out that locality isn't actually a principle of physics and now we have entanglement, Einstein's "spooky action at a distance."
- mxh 19y ago
  To the extent that thought experiments suggest real experiments, they are indeed valuable. I disagree that they can 'reveal ... results', however. For instance, Einstein's thought experiment was designed to 'prove' that QM was wrong. Obviously, that result was incorrect.

curi 19y ago

They have no clue what they are talking about. For example this: This is the same case with quantum suicide. When the man pulls the trigger, there are two possible outcomes: the gun either fires or it doesn't. In this case, the man either lives or he dies. Each time the trigger is pulled, the universe splits to accommodate each possible outcome Universes do not split like that. That would mean many universes were being created from nothing every instant. What actually happens is there are already infinitely many "universes" and they become different. And not one per outcome, but in proportion to the probability of outcomes.

angryprofessor 19y ago
>Universes do not split like that. That would mean many universes were being created from nothing every instant. What actually happens is there are already infinitely many "universes" and they become different. And not one per outcome, but in proportion to the probability of outcomes. It's not the writers of the article who have no clue. It's quantum physicists themselves. In the Copenhagen interpretation of QM, a conscious observer induces wave collapse (a random process). In this interpretation, there are no other worlds. In Wave Collapse/Many Worlds, a parallel universe is created in which wave collapse occured but gave a different outcome. There are different interpretations of QM (e.g. bohmian mechanics or GRW/stochastic collapse) which don't have this problem. If you are interested in QM, I strongly suggest looking these theories up. But Copenhagen QM (the theory in most textbooks) does have this problem. The reporter did an adequate job of explaining the consensus view. The problem is really that the consensus view can allow for nonsense such as what was described in the article.
- pfedor 19y ago
  "There are different interpretations of QM (e.g. bohmian mechanics or GRW/stochastic collapse) which don't have this problem. If you are interested in QM, I strongly suggest looking these theories up." I respectfully disagree. You can spend years reading about interpretations and the gain in terms of your understanding of Quantum Mechanics will be zero. For anyone interested in Quantum Mechanics, I strongly suggest actually trying to learn it, instead of dabbling into confusing popular articles the authors of the majority of which have never studied theoretical physics themselves. Please note I'm not saying that you don't know Quantum Mechanics. I just think your advice is bad. So here's my advice to anyone out there who feels that they want to know more. See the Schroedinger equation. Learn how to calculate energy levels for the harmonic oscillator and for the hydrogen atom. Read first six chapter's of Paul Dirac's "The principles of quantum mechanics". The time spent reading about interpretations and philosophical implications of QM is wasted. People who do research in theoretical physics devote very little time to such considerations, or no at all.
- curi 19y ago
  In Wave Collapse/Many Worlds, a parallel universe is created in which wave collapse occured but gave a different outcome. That is incorrect. Many Worlds does not say universes are created all the time, it says they already exist and become differentiated. BTW all the other interpretations are ridiculous attempts to avoid facing counter-intuitive facts. See, for example, David Deutsch's speech at the recent Everett conference http://www.philosophy.ox.ac.uk/misc/everett/Deutsch%20-%20Apart.wmv http://www.philosophy.ox.ac.uk/misc/everett/Deutsch%20-%20Ap...

joeguilmette 19y ago

haha quantum physics may as well be chinese to me. the only explanation that has ever made the least bit of sense is that cartoon with the old man super hero talking about light particles.

majimojo 19y ago

Nice movie plot for Jet Li perhaps, but they don't actually explain how to kill yourself in all universes. So, unless you're a cat or Solid Snake, you can get out of that box now.