5 ms·

A thought experiment seems to be exactly the opposite of an experiment: no experience there. I understand the concept, but every time I see one of these, the m

by narag 4y ago

A thought experiment seems to be exactly the opposite of an experiment: no experience there. I understand the concept, but every time I see one of these, the most compelling points are for me the ones that show how the setup makes no sense at all because, for starters, there's no way to make a real experiment that's truly equivalent. Edit-> please, think about this: can the "result" of any thought experiment be surprising, not what you expected?

svantana 4y ago
> can the "result" of any thought experiment be surprising, not what you expected? Isn't all of mathematics just thought experiments? No shortage of surprising results there.
- narag 4y ago
  That's not what thought experiment means.
  - svantana 4y ago
    Here's a thought experiment for you: consider the hypothesis that you're wrong.
n4r9 4y ago
> can the "result" of any thought experiment be surprising, not what you expected? Isn't Schrödinger's cat the classic example of this? Physicists at the time typically thought of quantum effects (like superposition) as being confined to the microscopic realm. Schrödinger pointed out that if you take the principles of quantum theory as serious and objectively ontological, then you end up with macroscopic superpositions.
- narag 4y ago
  The problem is that you can't know if the cat is dead or alive unless you open the box. Schrödinger conceived the experiment to "show" that the premises lead to an absurd result: that the cat is dead and alive at the same time. But now people either consider it plausible (in multiple universes or depending on observer) or try to explain how superposition is lost before it reaches macroscopic objects.
  - n4r9 4y ago
    Right, I agree with everything you say. To me that means the thought experiment was extremely valuable, because it generated a great refinement of our ontological ideas.
    - narag 4y ago
      It's funny because the author's idea was to discredit the notion altogether, so it's relevant because it failed to do that. The core of Mary's adventures is a false dicotomy: that matter is the only component of physical reality. But processes, structure and energy flow are as real as matter. Actually, at a very small scale, matter seems to be exactly that. So as usual with all these dualism "enigmas", the only problem is starting from an old perspective that doesn't play well with current knowledge. Consciousness seems to be a complex physical process seen from inside itself. There's no mistery or toughness in that, except that we can't compare it with anything else. We can't use the inside and ouside outlooks at the same time. But Wittgenstein already stated that more than a century ago.
      - n4r9 4y ago
        But... none of this makes thought experiments any less helpful or valid. If anything, the fact that Schrodinger's cat achieved the opposite goal implies that it touched on hidden fundamentals in quantum theory.
- MrPatan 4y ago
  Why is the cat never assumed to be able to be an observer? Or the flask with poison? I always assumed everybody understood "observer" to be shorthand for "some entity that irrevocably changes state because of the quantum events", but I'm starting to realize that lots of people, even the famous physicists responsible for the theories and experiments, may understand "observer" as "Human being, with a conciousness". I'm just a layman with a layman's understanding of quantum shenannigans, but.... am I too far off here?
  - n4r9 4y ago
    > some entity that irrevocably changes state because of the quantum events Yes, "observer" is ambiguous at best. One query with your proposed definition is: what do you mean by "irrevocable"? If you believe that the quantum state (wavefunction) is objective and independent - and does not collapse but evolves reversibly according to the Schrodinger equation - then nothing is irrevocable, it's just a technical challenge of "can we reverse the evolution of this patch of the universe". Yes, there is this decoherence process, but even that is reversible if you expand your "patch of the universe" sufficiently. Not many famous physicists believe human consciousness is required for a physical quantum collapse process to occur. John Bell put it nicely: > Was the wave function waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some highly qualified measurer—with a PhD? You might be interested to know that people have wondered about what happens if you replace the cat by something that is definitely an "observer": https://en.wikipedia.org/wiki/Wigner%27s_friend https://en.wikipedia.org/wiki/Wigner%27s_friend . Until the friend (F) tells Wigner (W) the outcome that he experienced when measuring a photon (P), then Wigner supposes that F is quantum entangled with P, i.e. they are in a joint superposition of states. However, the friend supposes that P is in a definite state.
    - MrPatan 4y ago
      > what do you mean by "irrevocable"? Very good point, who knows! I guess whatever the universe can't pretend didn't happen, like a photon being absorbed and re-emited by an electron. Which, what does that even mean? I don't know! Does anyone? I don't know!
DharmaPolice 4y ago
>please, think about this: can the "result" of any thought experiment be surprising, not what you expected? Not necessarily for the framer of the experiment, but that's not the point - it's to get other people to think about a problem in a different way.
- narag 4y ago
  That's exactly the point: to frame the "experiment" in a way that only admits the viewpoint of the framer. The only value is to analize why it's impossible to make it a real experiment.
lelanthran 4y ago
> Edit-> please, think about this: can the "result" of any thought experiment be surprising, not what you expected? The thought experiment is not to produce a new artefact that you would traditionally call "a result", like a table of subjects responses, or a histogram of responses, etc. It's to make the researcher consider stuff that cannot be tested, but might be feasible. > how the setup makes no sense at all because, for starters, there's no way to make a real experiment that's truly equivalent. That's the whole point. If you can make a real experiment, then it's not a real thought-experiment, is it? The article actually addresses this: > But this issue need not concern us, because philosophical thought experiments depend on logical coherence rather than practical feasibility. IOW, it depends on the argument being logically sound, not practically proven.
- narag 4y ago
  I do know what a thought experiment is. What I'm trying to point is that they never are really useful because the very reason that makes them unpractical is the reason that make them invalid. That reason is often shadowed by other reasons, but it's the fundamental flaw. You can turn that around: the differences between the reality and the alternate reality in which the "experiment" is possible are the key to the question.
  - lelanthran 4y ago
    > I do know what a thought experiment is. What I'm trying to point is that they never are really useful because the very reason that makes them unpractical is the reason that make them invalid. That reason is often shadowed by other reasons, but it's the fundamental flaw. I understand, but ... you don't judge whether something is useful (or not) according to some arbitrary goal, you judge based on the specific goal intended. In this case, the goal is "Does the process result in further lines of thought to exhaust, or further discussion?". I mean, you wouldn't call a brain-storming session useless if it resulted in a conclusion of "no practical implementation is feasible at this time", would you?
nautilius 4y ago
All conclusions drawn from “imagine shining a flashlight on a train riding close to the speed of light” revolutionized physics, so the answer is a very clear YES.
- narag 4y ago
  That's absolutely not correct. There are real experiments to prove Special Relativity and it has been corroborated multiple times. The train is only a way to explain it, not a thought experiment. Actually, some equivalent experiments to that are not just possible, but has been executed.
  - nautilius 4y ago
    I don’t think you understand what a thought experiment is and that explains your confusion in this thread.

by narag 4y ago

svantana 4y ago

> can the "result" of any thought experiment be surprising, not what you expected? Isn't all of mathematics just thought experiments? No shortage of surprising results there.

narag 4y ago
That's not what thought experiment means.
- svantana 4y ago
  Here's a thought experiment for you: consider the hypothesis that you're wrong.

n4r9 4y ago

> can the "result" of any thought experiment be surprising, not what you expected? Isn't Schrödinger's cat the classic example of this? Physicists at the time typically thought of quantum effects (like superposition) as being confined to the microscopic realm. Schrödinger pointed out that if you take the principles of quantum theory as serious and objectively ontological, then you end up with macroscopic superpositions.

narag 4y ago
The problem is that you can't know if the cat is dead or alive unless you open the box. Schrödinger conceived the experiment to "show" that the premises lead to an absurd result: that the cat is dead and alive at the same time. But now people either consider it plausible (in multiple universes or depending on observer) or try to explain how superposition is lost before it reaches macroscopic objects.
- n4r9 4y ago
  Right, I agree with everything you say. To me that means the thought experiment was extremely valuable, because it generated a great refinement of our ontological ideas.
  - narag 4y ago
    It's funny because the author's idea was to discredit the notion altogether, so it's relevant because it failed to do that. The core of Mary's adventures is a false dicotomy: that matter is the only component of physical reality. But processes, structure and energy flow are as real as matter. Actually, at a very small scale, matter seems to be exactly that. So as usual with all these dualism "enigmas", the only problem is starting from an old perspective that doesn't play well with current knowledge. Consciousness seems to be a complex physical process seen from inside itself. There's no mistery or toughness in that, except that we can't compare it with anything else. We can't use the inside and ouside outlooks at the same time. But Wittgenstein already stated that more than a century ago.
    - n4r9 4y ago
      But... none of this makes thought experiments any less helpful or valid. If anything, the fact that Schrodinger's cat achieved the opposite goal implies that it touched on hidden fundamentals in quantum theory.
MrPatan 4y ago
Why is the cat never assumed to be able to be an observer? Or the flask with poison? I always assumed everybody understood "observer" to be shorthand for "some entity that irrevocably changes state because of the quantum events", but I'm starting to realize that lots of people, even the famous physicists responsible for the theories and experiments, may understand "observer" as "Human being, with a conciousness". I'm just a layman with a layman's understanding of quantum shenannigans, but.... am I too far off here?
- n4r9 4y ago
  > some entity that irrevocably changes state because of the quantum events Yes, "observer" is ambiguous at best. One query with your proposed definition is: what do you mean by "irrevocable"? If you believe that the quantum state (wavefunction) is objective and independent - and does not collapse but evolves reversibly according to the Schrodinger equation - then nothing is irrevocable, it's just a technical challenge of "can we reverse the evolution of this patch of the universe". Yes, there is this decoherence process, but even that is reversible if you expand your "patch of the universe" sufficiently. Not many famous physicists believe human consciousness is required for a physical quantum collapse process to occur. John Bell put it nicely: > Was the wave function waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some highly qualified measurer—with a PhD? You might be interested to know that people have wondered about what happens if you replace the cat by something that is definitely an "observer": https://en.wikipedia.org/wiki/Wigner%27s_friend https://en.wikipedia.org/wiki/Wigner%27s_friend . Until the friend (F) tells Wigner (W) the outcome that he experienced when measuring a photon (P), then Wigner supposes that F is quantum entangled with P, i.e. they are in a joint superposition of states. However, the friend supposes that P is in a definite state.
  - MrPatan 4y ago
    > what do you mean by "irrevocable"? Very good point, who knows! I guess whatever the universe can't pretend didn't happen, like a photon being absorbed and re-emited by an electron. Which, what does that even mean? I don't know! Does anyone? I don't know!

DharmaPolice 4y ago

>please, think about this: can the "result" of any thought experiment be surprising, not what you expected? Not necessarily for the framer of the experiment, but that's not the point - it's to get other people to think about a problem in a different way.

narag 4y ago
That's exactly the point: to frame the "experiment" in a way that only admits the viewpoint of the framer. The only value is to analize why it's impossible to make it a real experiment.

lelanthran 4y ago

> Edit-> please, think about this: can the "result" of any thought experiment be surprising, not what you expected? The thought experiment is not to produce a new artefact that you would traditionally call "a result", like a table of subjects responses, or a histogram of responses, etc. It's to make the researcher consider stuff that cannot be tested, but might be feasible. > how the setup makes no sense at all because, for starters, there's no way to make a real experiment that's truly equivalent. That's the whole point. If you can make a real experiment, then it's not a real thought-experiment, is it? The article actually addresses this: > But this issue need not concern us, because philosophical thought experiments depend on logical coherence rather than practical feasibility. IOW, it depends on the argument being logically sound, not practically proven.

narag 4y ago
I do know what a thought experiment is. What I'm trying to point is that they never are really useful because the very reason that makes them unpractical is the reason that make them invalid. That reason is often shadowed by other reasons, but it's the fundamental flaw. You can turn that around: the differences between the reality and the alternate reality in which the "experiment" is possible are the key to the question.
- lelanthran 4y ago
  > I do know what a thought experiment is. What I'm trying to point is that they never are really useful because the very reason that makes them unpractical is the reason that make them invalid. That reason is often shadowed by other reasons, but it's the fundamental flaw. I understand, but ... you don't judge whether something is useful (or not) according to some arbitrary goal, you judge based on the specific goal intended. In this case, the goal is "Does the process result in further lines of thought to exhaust, or further discussion?". I mean, you wouldn't call a brain-storming session useless if it resulted in a conclusion of "no practical implementation is feasible at this time", would you?

nautilius 4y ago

All conclusions drawn from “imagine shining a flashlight on a train riding close to the speed of light” revolutionized physics, so the answer is a very clear YES.

narag 4y ago
That's absolutely not correct. There are real experiments to prove Special Relativity and it has been corroborated multiple times. The train is only a way to explain it, not a thought experiment. Actually, some equivalent experiments to that are not just possible, but has been executed.
- nautilius 4y ago
  I don’t think you understand what a thought experiment is and that explains your confusion in this thread.