I understand that the physics stack exchange community wants to see physics questions, not philosophical questions about things that are certainly unattainable. My question here is where you exactly put that boundary?

Some questions clearly are philosophical, like the question 'Does god exist?', while others are very clearly physical like 'If I shoot this projectile in those circumstances, then when will it hit the ground?'.

but there are those that lie somewhere in between, like a discussion of what happens to you if you fall in a black hole. Spaghettification is a logical consequence of the laws of gravity, yet this proces cannot be verified exerimentally even in principle, since no information can escape the event horizon of a black hole. Does that make it philosophical, or does the fact that it has a clear cut logical relation to a scientific theory of whom many aspects have been verified experimentally make it physical?

In other words I am talking about questions of the following form:

  • Does theory B logically imply statement A?,

where B is a theory that is widely accepted and of whom many aspects have been verified experimentally, and A is a statement that can't be directly experimentally verified in it's own right. I was assuming questions of this nature where considered physical and relevant, as it asks something about the logical structure of an accepted physical theory. Even if that particular aspect of it's logical structure can't be tested in the near future, it's still interesting to know weather that theory does or does not imply that. And there is a clear cut anwser to that, either the theory implies something or it doesn't imply it, so the discussion can be purely physical using the equations in the theory to argue rather than relying on vague philosophical arguments.

Is it a correct assesment that this POV of mine differs from the vast majority on this stack exchange, and a question is only considered legitimate if it is at least conceivably experimentally verifiable in the near future?

The reason I ask this question is because of the fact that, to my surprise, this question wasn't well recieved: Does relativity of simultaneity prove determinism?

Is it correct that that is because, even though the question is logically linked to a well established scientific theory, it isn't directly experimentally verifiable and therefore isn't considered legitimate? And should we then conclude that if someone asks, say, something about the spaghettification process in a black hole and where that comes from, this question should be considered illegitimate too since that proces is experimentally unaccecable? More generally, are questions about predictions of well established scientific theories not allowed if those predictions can't be(in the near future) tested experimentally?

If that is the convention used here, then I agree my question was off topic and I should ask it to the philosophical community. Even though I am convinced that people with a background in physics will have more relevant and good anwsers on questions in the above form than those with a philosophical background, as a good understanding of the physical theories those questions are embedded in are necessary for giving good anwsers.

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    $\begingroup$ Related: physics.meta.stackexchange.com/q/6284/50583 $\endgroup$
    – ACuriousMind Mod
    Commented Nov 25, 2017 at 17:17
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    $\begingroup$ From my personal point of view you'd have a lot easier time making the case that the question is interesting if your discussion of it had addressed the elephant in the room (the intrinsic limits on causality that are built into the theory). $\endgroup$ Commented Nov 25, 2017 at 18:17

2 Answers 2


No, your assessment is not correct. Questions of the form "Does theory B logically imply statement A?" where B is a mainstream theory and A is not experimentally verifiable in the near future are not generally off topic. Of course specific cases may be off topic for different reasons.

However, remember the distinction between a question being off topic, and being bad. Questions that are bad should get downvoted; questions that are off topic should get put on hold (a.k.a. closed). Note that your question, as I write this, has been heavily downvoted but it has not been closed. There is no indication that the community considers it off topic.

I don't know if I can give a general rule for identifying when questions are too philosophical. Right now we decide such things case-by-case because they come up rarely. Perhaps by looking at many examples, someone could come up with a fairly general rule, but as far as I know that hasn't been done yet.

  • $\begingroup$ Note that the question at hand has now been closed - though I think it's a toss-up as to how much the meta effect contributed. $\endgroup$ Commented Nov 27, 2017 at 17:09

If it's covered in mainstream physics, well that's obviously physics.

If it's about God, it should be closed.

If it's about the inside of a black hole, that's chat room.


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