We seem very undecided on main on whether magnetic monopole do, in fact, exist or not, or whether this question is settled at all.

It doesn't seem correct to me that to such a basic EM question we would give different answers all the time. The answers on main should be consisten and clear — especially when the answers come from our top users.

Or am I missing something?

To be clear, I have no reason to doubt the good faith and competence of all our esteemed answerers, however they can't all be correct at the same time.

Can we please review the answers to make sure they are correctly worded?

# Undecided

What should be done in this case? What is the correct approach?

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## closed as off topic by David Z♦Jan 13 '13 at 20:23

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I think that you have mischaracterized physics.stackexchange.com/a/5575/520: I say "It is an open question...". Likewise, many of the other's in that category are in the subjunctive and depend on some unproven theory being true: only a few are strongly stated. –  dmckee Jan 8 '13 at 21:47
@dmckee I didn't mean to pass judgement, but simply to show divergence. That particular answer was characterised as a yes because of the sentence "theoretical prejudice favors their existence" (so, to me, it reads more like a conditional yes) - but, feel free to move around the answers you think are miscategorized! –  Sklivvz Jan 8 '13 at 21:50
I don't think the categorization of any particular question affects your point. Though physics.stackexchange.com/a/5585 may not have been the one you meant. It doesn't seem to say anything on the subject. –  dmckee Jan 8 '13 at 21:53
You have encountered the phenomenon that physics.se is not a 'we', or a democracy, whose goal is to reach a consensus. There is no 'we' who are undecided. Rather we have separate individuals with different levels of physical understanding. Its a perfectly acceptable situation that some people know that monopoles exists, while someone else doesnt. –  user1708 Jan 9 '13 at 14:49
Perhaps a summary of the discussion here would be good to put in the tag wiki for the magnetic-monopoles tag. –  Mark Booth Jan 11 '13 at 10:46
Personally I left this question alone so far, but I think it's pretty clear that that turned out to be a mistake. As the answers explain, this is a community. Sometimes answers will disagree with each other, sometimes they will seem to disagree until you read them closely; all we have to do is downvote the wrong ones and upvote the right ones. No need to enforce homogeneity. I'm closing and locking the question to prevent further arguments. (People who had comments deleted: please think carefully before posting such things in the future, as some of them were inappropriate) –  David Z Jan 13 '13 at 20:22

As paradoxically as it may sound, the apparent discrepancy (on whether magnetic monopoles exist or not) may to a large extent boil down to semantics and the use in different context.

E.g.:

• Are we discussing 1) a model? 2) the actual universe? 3) only our local vicinity of the universe? 4)...?

• By the word existence, do we e.g. mean 1) have been directly experimentally observed? 2) have in principle a non-zero (but so far unobserved) abundance? 3) could under the right conditions be created? 4)...?

On one hand, magnetic monopoles (and more generally dyons) have so far not been experimentally seen. On the other hand, many theoretical physicists have very little doubt that they exist. For instance, J. Polchinski writes in the conclusions of this paper that

[...] the existence of magnetic monopoles seems like one of the safest bets that one can make about physics not yet seen.

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Since I saw this discussion, I have been confused about why this is in any way "controversial". I completely agree with this answer, this essentially boils down to semantics. If a question is asked accurately, then I don't think there will be any disagreement in the answers. For example 1) Have magnetic monopoles (mm) been seen experimentally? 2) Under which conditions does theory X require mm exist? 3) Does the observation of emergent mm's, imply the existence of fundamental mm's? –  Heidar Jan 9 '13 at 16:58

The situation is actually pretty clear

• There have been exactly zero observations that people believe. Read the comments on http://physics.stackexchange.com/a/1403/520 and you'll hear about one possible observation with a machine still being commissioned, which does make for fun speculation.
• There are several distinct ways in which their actual existence would be "beautiful", and many people carry some level of belief that they do exist.
• Only a few people in the know use strong language in stating their belief, but such people do exist.

For those that are interested my personal position is a kind of weakly committed optimism, tempered with the knowledge that it doesn't matter unless we can get a hold of a few to play with.

• the "no"s are addressing observation and say so
• the "yes"s are most in the subjunctive mood relying on some theory or state that they represent a preference rather than outright knowledge.
• a lot of the "undecided"s try to express the subtleties of the situation

## What should we do?

Well, what I do is downvote and comment on things that are outright wrong, but more or less the only thing that would qualify is a claim that there are confirmed observations of magnetic monopoles, and just comment on things that I think are too strongly stated (mostly claims that it is a theoretical certainty or conversely claims that the zero on the RHS of $\nabla B = 0$ proves that there are no monopoles rather than expressing the non-observation of them to date).

In short

• if you think an answer is wrong, downvote it.
• if you think an answer is misleading a comment or alternate answer should be used to clarify.
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Dear @dmckee, you seem to mix up several different questions. First, whether magnetic monopoles have been observed so that we would know their mass etc. The answer is No. Second, whether the scientific evidence indicates that magnetic monopoles exist. The answer is "we don't know for sure but it's more likely that they do". Whether they exist is a question in particle physics and one needs beyond-the-Standard-Model theories to settle these questions. A majority of motivated grand unified and similar theories says "Yes they exist" which is why most particle physicists think that they do exist. –  Luboš Motl Jan 9 '13 at 6:46
Let me emphasize the point that one could hypothetically reach the status of "theoretical certainty" even without/before the observation of the monopoles (I don't claim we're there). For example, lots of other evidence for a grand unified theory or their class could accumulate and the monopoles would be an inevitable consequence of this theory, as they usually are. I think it's obvious that people should up/down vote according to their perception of validity in particular and magnetic monopoles aren't special in this sense. There are tons of other questions that are apparently "controversial". –  Luboš Motl Jan 9 '13 at 6:49
One more point I said and want to emphasize. It's silly to single out magnetic monopoles as an open question - physics is flooded with open questions. It follows from its nature of work in progress, like for any science. It's silly to "ban" discussions on open questions because they are what scientific research is all about and every open question today may become a settled one tomorrow. There is no God-given permanent boundary between open and settled questions. –  Luboš Motl Jan 9 '13 at 6:56
And sociologically, it's also true that many advanced, more well-informed physicists know that some questions considered open by the broader public are actually settled. The opposite case arguably also exists even though it's more rare. –  Luboš Motl Jan 9 '13 at 6:58
@LubošMotl, the question though is about discrepancies in the answers and not about a particular stance. It's more about kindly asking answerers to specify better if they are discussing a hypothesis or a theory. Think about high school or undergrads reading our site, would they understand what the correct view of monopoles is? –  Sklivvz Jan 9 '13 at 7:55
The only task for us is to be smart, well-informed, and use the up/down votes in such a way that higher quality answers will end up higher than lower quality answers. Ultimately, the position boils down to polls in which ignorant users are as important as knowledgeable users. But despite this "imperfection", answers may be written in such a convincing way that they will make some people change their mind. At any rate, the existence of open questions is an inseparable part of science and it's silly to try to impose a consensus about questions that are not settled. –  Luboš Motl Jan 9 '13 at 12:37
Why have all the comments been unilaterally deleted? Lubos and Dilaton had +6 upvoted comments. –  Ron Maimon Jan 13 '13 at 20:36
@RonMaimon I still see most of the comments. Is it possible that you machine has gotten it's javascript corrupted in the cache? Force reload will sometimes fix that as will clearing the caches. –  dmckee Jan 13 '13 at 20:42

Speaking as one amateur, not only am I not confused by conflicting answers about physics at the forefront of research, I welcome them.

Here is why:

• Experts may disagree. This is true for horticulture, philately, linguistics, medicine... why should it be different for physics.
• Disagreement sparks efforts by proponents of a particular approach to clarify and amplify their reasoned point of view. This is a good thing.
• Experts give opinions, they do not demand that their word be taken as the gospel truth or else. An expert witness giving courtroom testimony is not dictating the outcome of a trial, she or he is offering an opinion to the best of her knowledge and belief. It is up to the jury or judge hearing the testimony to weigh the testimony of this and any other expert witnesses and make up their own mind. However, this is not a courtroom and no verdict is required, hence the supposed "problem" is pretty much a non-issue.

While it is possible that some visitors to a Q&A site come here expecting to find out only uncontested, "official" Answers (or alternatively, that any Answer not uniformly held by the expert community be prefaced by a qualifier such as "speculative"), this is an unreasonable expectation. On the contrary, the opportunity to find out that such naive expectations cannot be fulfilled is a valuable learning experience.

Hence I propose that this question be closed as unproductive.

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I'm late to the party here but I've had a chance to read through everything and here is my take on it...

I think, first, something seems to be lost in translation. Yes, this particular topic is about magnetic monopoles. But I think that just happens to be used as an example -- I can make a list of questions about "why do airplanes fly" and there will likewise be contradictory answers, some of which are incorrect or speculative. I think this was chosen as an example of questions with contradictory answers and shouldn't be read-into as anything more than that. It's not an attack on theoretical physics, or cutting-edge science, or issues with BSM. It's just making a list that highlights a question that deserves some further thought.

With that out of the way, I see nothing wrong when a user finds a series of questions that have seemingly contradictory answers with that user posting a question just like this in meta and asking for a review from experts. The system is set up so good answers get upvoted, bad ones get downvoted, and experts answer the questions asked.

So there is absolutely no harm with posting a list of questions and saying "Could somebody who knows what they are doing review these because they are not consistent." And people who know can go through and review, up/down vote accordingly, or post new, more correct, more up-to-date answers.

It's no different from the "re-tag old questions" style of post that asks users to look at old questions and verify the tags are correct.

So if you want a policy, my suggestion is this:

If you come across a series of questions on a similar topic and you think they present contradictory information, post in meta the list of questions and ask for review by experts. These experts should review the questions and will let the system work the way it should work and all will be right in the world.

No use trolling, or flaming anybody, or accusing people of attacks on a particular subject. That gets us nowhere as individuals or a community.

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Magnetic monopoles are among the many beyond the standard model predictions of certain theories, which are at present not directly experimentally established but they are not experimentally ruled out either. In principle, they can exist even if it is (at present) not (by our technical means today) possible to detect them directly. Not the important difference between direct and indirect detection of beyond the standard model physics.

It is a natural thing that experimental physicists are often more sceptic about beyond the standard model physics, such as magnetic monopoles, supersymmetry, extra dimensions, and other things then theoretical physicists. This explains the wide spectrum of different answers.

There is absolutely nothing wrong with having a wide spectrum of answers about not yet settled down issues. Finally, nature will tell us what is right and what is wrong.

So in my opinion, absolutely nothing should be done about the different answers concerning magnetic monopoles and other beyond the standard model physics. Of course, trolling about such topics and attacking people who work experimentally and theoretically beyond the standard model physics should not be allowed on a serious physics question and answer site as Physics SE is supposed to be. However questioning such ideas for physical reasons is a good and healthy thing.

So I am strongly against any special treatment of questions and answers about magnetic monopoles, other BSM physics, certain cosmological topics, etc here on physics SE. We should trust the judgement of the community and let thing happen by votes exactly as it has always been done up to now. Just let things be as it is and as it has always been, these actively researched topics belong to the well accepted mainstream theoretical physics so they should not be singled out.

Summary: Absolutely nothing has to be or should be done, it is absolutely natural and legitimate for questions about open issues to have such a spectrum of answers as Lubos, Dmckee, and Qmechanic have explained.

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This post has been locked due to the high amount of off-topic comments generated. For extended discussions, please use chat.

To understand better: if the issue is "not settled" as you say, is it then acceptable to have an answer that says "it is settled"? –  Sklivvz Jan 8 '13 at 23:27
@Sklivvz because it is not settled down, you have people who are quite sure that a certain BSM phenomena exists from theoretical reasons and other people who are very sceptic for experimental reasons. The scientific method is an interplay between theory and experiment. At times, experiments lead to theoretical ideas and sometimes, theoretical ideas are ahead of the experimental possibilities or technologies we have at present. There is absolutely nothing about having these two opinions about topics that can not be settled down at present. Please, nothing has to be done about these monopole –  Dilaton Jan 8 '13 at 23:32
or other BSM physics questions and answers. Only unscientific trolling and bullying should not be tolerated here. I get the impression (maybe I am wrong) that your opinion goes rather with experimental people who are very sceptic about such things, this is ok. But if people say there are rather confident that BSM physics has to exist for theoretical reasons, there is nothing wrong with this either. So please, do not try to make an issue where there is none. –  Dilaton Jan 8 '13 at 23:35
It seems to me that we are not understanding each other. There's a difference between postulating a hypothesis, and passing a personal opinion as scientific fact. The first is correct and to be encouraged in science, the second is basically incorrect or fraudulent. At a personal level, I totally agree with you: there are good theoretical reasons to suspect they exist but no practical confirmation yet. So "we don't know, yet" (cont.) –  Sklivvz Jan 8 '13 at 23:36
But some of the answers above, do not present the objective current state of knowledge in a correct fashion. It's pretty obvious that it's a contentious subject and it should be treated fairly. So basically, some of them are literally unscientific trolling to use your words (even though I do not see any bad faith, to be honest, but just opinions expressed in an incorrect way) –  Sklivvz Jan 8 '13 at 23:37

To me, this seems to be a subset of a larger question:

### "What do we consider as "true" on physics.SE?"

Basically, here I see that some of BSM physics is considered to be perfectly valid by most theoretical physicists, while others feel that the absence of any experimental evidence means that they ought to be portrayed as "postulated".

I personally feel that we should not put any policy regarding this. There is no strict "boundary" delineating "open" and "settled" questions in physics, people have different beliefs about this. Magnetic monopoles are an example of this. Even black holes are an example of this, at a stretch -- we have objects in the universe which we think are BHs, but we can't be 100% sure. Should we stop letting people say that BHs exist on this site? Certainly not. The same goes with magnetic monopoles.

Making our site adhere to a certain picture of "truth vs hypothesis" would be destructive for the site -- we generally strive to be agnostic in these matters when dealing with mainstream physics.

Instead, what I suggest is the following. It is not a policy, it is just a courtesy that I suggest others follow:

When dealing with topics that are not widely accepted by the entire physics community in general, try avoiding absolute statements like "magnetic monopoles exist". Instead, say that "MMs have been postulated to exist, due to <reason>. Assuming they exist, <rest of answer>". This makes the answer clearer to others, and prevents misconceptions of its tone.

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Do you mean this for questions which explicitly ask about a BSM theory, rather than a particular object/particle?? If so, I don't think this is very practical. For example, if the question is "Why is there no open oriented strings?", I don't think it is practical to write "Strings have been postulated to exist; Open strings have been postulated to exist; Oriented strings have been postulated to exist; Supersymmetry has been postulated to exist; Supercharges have been postulated to exist - 32 for ... , 16 for ... ; ... It takes too long. –  Dimensio1n0 Jun 30 '13 at 12:11
@dimension10 Only for contentious topics -- ones on which there are hot debates. Like monopoles. On a question on strings, it's sort of a given that you assume they exist (etc etc). And it's only a courtesy. Supersymmetry(/etc) doesn't spark hot debates (usually), so it's OK to just assume. On the other hand, MMs are still prone to flamewars. –  Manishearth Jun 30 '13 at 15:52