Is it permitted or not or frowned upon?

I couldn't find a tag for it.

But I hope you'd rather see discussions about "what is physics?" and "falsifiability" (and some of the stuff that Smolin complains about) here among physikers, than in a purely philosophy-bent forum.

Can we ask in the Physics.SE about whether or not the following is science or is still philosophy:

1. string theory,
2. M theory,
3. multiverse?

Just curious.

Grateful for any response, including downvotes.

• The tag philosophy was there; but it has been removed now. – user36790 Dec 25 '16 at 5:18
• Related: Can we get rid of the “philosophy” tag? $\uparrow$; Should we allow philosophical / interpretational questions? - possible dupe; About Physics and philosophy. – user36790 Dec 25 '16 at 5:24
• There is Philosophy.SE too if OP is not aware of it. – user36790 Dec 25 '16 at 5:29
• i am aware of it. but i want to get sorta technical about the meaning of "falsifiability" and what this may mean regarding the "demarcation problem". And, about physics, i sorta wanted to ask specifically what side of the mark those three topics are. Or arguments supporting any particular view. i really want the question to be about science, and particularly physics, than about philosophy which i know as little about as a schlub. – robert bristow-johnson Dec 25 '16 at 5:56
• okay, i looked at this and i can see i am 5 years late for the discussion. but any discipline has a philosophy of that discipline. i would think that physicists would like to weigh in with other physicists about what is physics (or what isn't). is string theory "science" yet? is falsifiability necessary? if not, what demarcates science from what it is not? if so, how is string theory eventually going to make a falsifiable prediction that differs from the status quo. – robert bristow-johnson Dec 25 '16 at 6:03
• Note that on meta it is generally considered unbefitting for OP to accept an answer that lacks consensus from the Phys.SE community. Meta is supposed to decide site policies in a democratic fashion that reflects the majority's (rather than OP's) opinion. Related: When do you accept an answer on meta? – Qmechanic Dec 28 '16 at 15:55
• @Qmechanic : science is not a democracy, and the last time I looked it was a free country, with free speech in science. – John Duffield Jan 6 '17 at 16:33
• @JohnDuffield: Your free speech is not being quelled, and consensus on site policy is far from science. So neither of your two points make any sense with respect to Qmechanic's comment. – Kyle Kanos Jan 6 '17 at 17:11
• i agree with you @KyleKanos (John, "Freedom of the press belongs to those who own one"), but i feel that John's earlier point is interesting: "So, discussion of whether it's pseudoscience is off topic, but the [alleged] pseudoscience itself isn't." That seems to me to be a very valid point. – robert bristow-johnson Jan 6 '17 at 18:31

You can ask any such question of me.

Is it permitted or not or frowned upon?

From moderator David Z's response, it looks like such questions are frowned upon. For myself, I think that if you can't ask physicists about this stuff, and if instead you're sent away to some philosophy forum with a flea in your ear, that's not right.

But I hope you'd rather see discussions about "what is physics?" and "falsifiability" (and some of the stuff that Smolin complains about) here among physikers, than in a purely philosophy-bent forum.

I would. I view Sean Carroll's stance on falsifiability with alarm.

Can we ask in the Physics.SE about whether or not the following is science or is still philosophy: 1.string theory, 2.M theory, 3.multiverse? Just curious. Grateful for any response, including downvotes.

Maybe you can't ask on Physics.SE, but while we're on the subject, let me say this: there's no evidence for string theory or M-theory. And none for the multiverse. These hypotheses remain speculative even after many decades. Moreover the M-theory "brane-leak" claim as to why gravity is so weak contradicts GR, and the Goldilocks multiverse "just right" claim contradicts running constants. On top of that these speculations can never be disproven, and as such they're on a par with religious promises and claims. They aren't science. What they are is pseudoscience popscience masquerading as science.

• Given the historical evidence for Jesus existing, does that mean you do admit the theories as factual? Or are you just as confused with history as with modern physics? – Kyle Kanos Dec 26 '16 at 19:29
• I'm not confused at all. There is no evidence for some angel telling some shepherds that their saviour has been born to them. There is no evidence for five loaves and two fishes feeding five thousand. Et cetera. In similar vein there is no evidence for string theory, or M-theory, or the multiverse. – John Duffield Dec 26 '16 at 19:40
• Okay, you're talking about the Divinity of Jesus, not his existence. These are two distinct events: one for surely happened (the existence) and one is part of the Deposit of Faith. Would you mind amending your answer to reflect this? Otherwise, you'll look the fool. – Kyle Kanos Dec 26 '16 at 19:42
• The fact that this answer instantly generated an off-topic discussion of religious historiography is a good cautionary reason for Physics to be very cautious about accepting mostly-philosopical questions. – rob Dec 26 '16 at 21:41
• I hope the down votes on this answer are for the final paragraph (which is not an answer to the meta question and phrases its own strong philosophical stance in an overly rhetorical manner) rather than for the rest of the answer, which seems very reasonable to me. (So +1 for it.) – Nathaniel Dec 27 '16 at 4:44
• @rob I agree that there is a statistical correlation between philosophical discussions and irrelevant tangents, but I don't see that as an a priori reason not to accept philosophical questions. I think it happens largely as a result of scientists tending to have inadequate training in philosophy (e.g. on how to make an argument based on logical reasoning rather than retoric), and consequently we'd all benefit from more philosophical content, if the tendency toward run-on discussions can be effectively curtailed. – Nathaniel Dec 27 '16 at 4:53
• @Nathaniel I don't think it's an a priori reason to reject such questions either. (I seem to have written "caution" twice in my previous comment, which is very different from how I'd approach a topic that clearly belongs elsewhere.) From a moderator's perspective: if we have some topic that's tangentially related to our core topics, but it makes people get all fighty with each other and high-quality contributors get huffy and leave, then that's a topic we can let people discuss elsewhere. – rob Dec 27 '16 at 22:13
• thanks for the answer John. i think i will give it my check mark just to send a message – robert bristow-johnson Dec 28 '16 at 4:24
• @rob fair point about caution vs. reject, I agree that caution is good. I agree with the rest of what you say as well, but I also think we have to be cautious about not using "this is philosophy" as a reason to reject otherwise good questions. (In the past that's happened a lot to questions on quantum foundations.) – Nathaniel Dec 28 '16 at 10:17
• I think the last paragraph is a tad over the top, considering there are many people on this forum who do believe in, as you put it, "sweet baby Jesus". (Also, for that matter, methinks the language there is a bit strong - "horse----" doesn't really fit with the be-nice policy.) Finally, there are string theorists on this site and people who work in those fields of physics you mentioned. No need to insult them, they're already insulted enough. – heather Jan 6 '17 at 15:33

You called it in the comments: no, those questions are generally off topic here. We consider things like the meaning of falsifiability not to be physics. They can be of interest to physicists, but that is not the criterion we use to determine what is on topic.

For material of this nature, I suggest going to Philosophy Stack Exchange and checking their epistemology and philosophy-of-science tags.

• yeah, i just would rather have the discussion in the midst of physikers. the philsophy.se has some solids and some fruitcakes. and i want the discussion to be sorta technical. what is it that constitutes empirical proof? if a theory is "true" (whatever the hell that is), how does it do something different from this other competing theory, if they predict the same outcomes. doesn't there have to be an outcome that comes out different to identify a new theory as new science? – robert bristow-johnson Dec 25 '16 at 6:59
• You could always try in Physics Chat. – David Z Dec 25 '16 at 6:59
• So, discussion of whether it's pseudoscience is off topic, but the pseudoscience itself isn't. – John Duffield Dec 26 '16 at 17:02
• @JohnDuffield, i may have been your only up arrow. i liked your comments at the Sean Carroll site. i really do believe that the issue of falsification, how historically accepted theories have stood the test and then later been falsified, and of course the demarcation "problem". – robert bristow-johnson Dec 28 '16 at 4:22
• @robert bristow-johnson : all points noted. Thanks for the check. I don't think there is a demarcation problem myself. Evidence is evidence, the scientific method is what it is. Of course, people who can't offer any evidence beg to differ, and make siren calls for falsifiability and thus the scientific method to be jettisoned. I will never agree with that. – John Duffield Dec 28 '16 at 11:45
• "Evidence is evidence" is a tautology, @JohnDuffield . the issue is what specifically is the role of evidence in physics, science, or any epistemology? – robert bristow-johnson Dec 29 '16 at 6:12

Your queries about philosophy applied to things like grand unification (M-theory, string theory) are discussed in the book, String Theory and the Scientific Method which may be of interest to you. The book addresses more general issues such as testability for a theory, and Bayesian analysis.

Also, to address your question about whether string theory or M-Theory is philosophy or science, it is obviously science. String theory emerged originally from bootstrap approaches to the S-matrix, and later on the worldsheet action was developed. What emerged was to a large extent simply the product of exploring their consequences and the constraints they give rise to.

Maybe to posit the starting point may be argued to be philosophy, but the process by which we have explored the framework that is string theory is certainly scientific.

• so to be obviously science, is it necessary to be falsifiable? does string theory or M-theory explain an interaction or behavior that GR and SM do not? – robert bristow-johnson Dec 25 '16 at 22:16
• How is this an answer to the question as actually posed? – Emilio Pisanty Dec 28 '16 at 0:02
• If reason -philosophy?- says that some fundamental concept or idea in physics doesn’t make sense, then that is relevant to physics, not to philosophy -it couldn’t care less. – Anton May 1 '18 at 0:56