Personal view on the problem: mutual exclusivity is is not strongly enough suggested by the language use by the description of science-based and hard-science. I'm suggesting replacing the "contrast with" with a wording explicitly asking for "mutual exclusivity".

Here goes my argumentation:

science-based For questions that require answers based on hard science, not magic or pseudo-science, but do not require scientific citations. Contrast with the hard-science and reality-check tags.

hard-science - Requires answers backed up by equations, empirical evidence, scientific papers, other citations, etc. Contrast with: science-based and reality-check tags.

My natural expectations, I can put pink and crimson in contrast and perceive they are different - depending on the context, they can be even strongly contrasting. But I can mix them and the result is still a tint of red. Thus, to me the "contrast" wording does not suggest the "don't mix them, they are mutually exclusive".
Which illustrates the core of the problem: the reliance on on a wording that may be expected to vary from "perceiver" to "perciever" and from context to context.

There are other examples of tag definition, which are better (more explicit) in this regards. For example

magic - For questions that have to do with magic, as opposed to science/technology.

Now, this one is more clear in saying "don't mix magic with any science or technology related tags" and I argue that the use of "opposition" (rather than "contrasting") will make the intended use of science-based and hard-science clearly mutually exclusive.
I can imagine a single wording that is even more unambiguous, and this is straightly saying "science-based is mutual exclusive with hard-science" and vice-versa in their respective descriptions.

Yes, I'll grant the point that my "natural interpretation" on the semantics of "opposed" may be askew with the majority of native English speakers, among whom I'm not. And in the same situation are lots of other WB/SE users.
I don't think it would be fair to ask them to "learn first proper English" when a cheap solution to prevent the misunderstanding exists.

The problem is compounded with the expectation one develops by being exposed to the tags - most of the delimit a class of topics (biology, warfare, evolution), with "you can mix them" being mostly the rule rather than the exception.

Now, I understand there is a need to have exceptions to the rule, but it's only fair to:

  • signal those exceptions unambiguously (if "mutual exclusivity" is intended, why not directly saying so?), and maybe...
  • present the user a link to the rationale for those exceptions. After all, those exceptions explains are based on existing needs of the WB site and will inform the user in a context where the explanation makes immediate sense.

All in all, I think that things like this can improve the user experience. As it stands now, the "friction" between the 'user expectations' and 'WB site needs' is high enough to create non-trivial chances for a question to be rejected and the user getting into the idea of "rules that come to bite you just because you didn't take the effort to discover - in an amorphous corpus of law and who know how big - what rules are relevant in a certain situation".

I don't know about others, but were those situations to happen to me enough times, I will prefer to avoid WB rather than take the unknown maybe huge effort to discover "what is to be a good citizen who is not gonna be punished".

Here, they are contrasting. Not the most striking contrast, by still a strong contrast within the context. And yet they are a shade of red.

enter image description here

For reference and, alone, not bearing strong significance to my proposal - all started from the discussion in the comments in here.

  • $\begingroup$ Would I be correct in saying that the core thrust of this post is you feel that the descriptions for the science-based and hard-science tags don't do a good enough of indicating their mutual exclusivity? $\endgroup$
    – sphennings
    Oct 11, 2021 at 2:47
  • $\begingroup$ Yes - as (I hope) the title of my question indicates. Additionally, I'm saying that the issue can be easily corrected and that I may not be the only one to feel the same. $\endgroup$ Oct 11, 2021 at 2:50
  • $\begingroup$ When used as an adjective "interpretable" is generally used in contrast with "uninterpretable". So the first sentence of your title reads as "The descriptions can be understood". If you want to to say "can be interpreted ambiguously" you'd want to use something like "Is ambiguous" or "Could be interpreted as being non-mutually exclusive". $\endgroup$
    – sphennings
    Oct 11, 2021 at 3:17
  • $\begingroup$ @sphennings Did you mean "in opposition to uninterpretable" (the latter being more than just "showing strong differences upon comparison")? Anyway, I attempted to fix my title. $\endgroup$ Oct 11, 2021 at 3:23
  • $\begingroup$ No I meant in contrast. Though opposition also works. $\endgroup$
    – sphennings
    Oct 11, 2021 at 3:25
  • $\begingroup$ @sphennings To me "un" means negation. While the opposite can be described as contrasting, not everything contrasting is in opposition. $\endgroup$ Oct 11, 2021 at 3:28
  • $\begingroup$ In the context of my previous comment the words can be used interchangeably. If you're interested in the nuances of why someone would choose one word over the other I'd suggest asking people on english.stackexchange.com. They can do a better job of explaining the quirks of this language, than I can in a comment. $\endgroup$
    – sphennings
    Oct 11, 2021 at 3:32
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    $\begingroup$ @sphennings If one needs to go to english SE to be able to contribute to WB, something is wrong. Especially when it's easy to make sure that the intention and the wording is in absolute concordance. Otherwise, I'll take a trip there when time allows, thanks for the suggestion. $\endgroup$ Oct 11, 2021 at 3:38
  • $\begingroup$ We don't expect anyone to never make mistakes. This comment section is not the best place to help resolve all of them. You seem genuinely interested in understanding so I suggested a site that is dedicated provide higher quality answers than I ever could provide. $\endgroup$
    – sphennings
    Oct 11, 2021 at 3:46
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    $\begingroup$ I just made an edit so that you're quoting the description for the hard-science tag. $\endgroup$
    – sphennings
    Oct 11, 2021 at 4:03
  • $\begingroup$ @sphennings Thanks. Also, third time's the charm :) (the "contrast" tags were still incorrect) $\endgroup$ Oct 11, 2021 at 4:12
  • $\begingroup$ I do not think that 'Contrast' here refers to mutual exclusivity at all. This is an invitation to read the descriptions for the tags following 'Contrast with'. I believe this comes from 'compare and constrast' idiom. $\endgroup$
    – Otkin
    Nov 5, 2021 at 16:31

2 Answers 2


I think as written it's pretty clear that the tags are mutually exclusive.

From the hard-science tag

Requires answers backed up by equations, empirical evidence, scientific papers, other citations, etc. Contrast with: science-based and reality-check tags.

From the science-based tag

For questions that require answers based on hard science, not magic or pseudo-science, but do not require scientific citations. Contrast with the hard-science and reality-check tags.

If you contrast these two descriptions you'll note how the primary difference between the tags is whether citations are required or not required. While we don't currently explicitly say "these tags are mutually exclusive" it should be clear from their descriptions that if you have both tags on a post you're both requiring and not requiring citations.

A note on the usage of "contrast with"

In these tags we say "contrast with". What we mean by this is "you should compare with and note the differences". This is a pretty standard usage of the word.

This is done so that people can see the two tags, consider how they differ and select the one (since if used together they are contradictory) that suits them best.

  • $\begingroup$ And I think if "mutual exclusive" is intended, it worth wording it as "mutual exclusive" with no room for interpretation differences arising from any causes (from cultural background differences to awareness of the rationale for the choice to intellectual ability of the reader). Not that is a lot to ask. Or... is it? $\endgroup$ Oct 11, 2021 at 4:32
  • $\begingroup$ @AdrianColomitchi I don't think we intended them to be mutually exclusive but as we clarified the differences between the two tags by definition they became mutually exclusive. $\endgroup$
    – sphennings
    Oct 11, 2021 at 4:35
  • $\begingroup$ If the intention changed along the way and now they are meant to be understood as "mutually exclusive", it would be only fair to reflect the change for the travelers that joined later. $\endgroup$ Oct 11, 2021 at 4:44
  • $\begingroup$ @AdrianColomitchi That should be clear from how you cannot both require and not require citations. $\endgroup$
    – sphennings
    Oct 11, 2021 at 4:46
  • $\begingroup$ Should but it isn't. "Citations not required" doesn't mean "citations forbidden". There's no contradiction between the two description, hard-science being more the restrictive (in requesting citations or demonstrations using formulae) form of science-based. It is only this obscure discussion that documented the decision "from now on, by convention, the two tags are meant as two mutually exclusive values on the sciency axis" (ctnd) $\endgroup$ Oct 11, 2021 at 5:00
  • $\begingroup$ Is anyone going to consider this answer as a "low quality" only because it makes use of diagrams and citation and links to online calculations and thus is not quite science-based but more hard-science-y? (ctnd) $\endgroup$ Oct 11, 2021 at 5:04
  • $\begingroup$ From my point of view, it's also about the friction a contributor experiences in her interaction with the site. The higher this friction, the less the number willing to relevantly contribute. There ain't such a thing as "rules good forever and beyond" - if one sees herself in a "reached the Nirvana perfection", that one is dead. $\endgroup$ Oct 11, 2021 at 5:11
  • $\begingroup$ Actually, I've never understood the mutual exclusivity of these tags. As I see the whole situation, a fictional setting can be founded in fictional science or real science. (E.g., warp drive vs chemical rockets.) I look at these worldbuilding queries as somewhat overlapping domains: a fictional science question about warp drive will almost certainly involve real world science in some capacity and may well ask for some hard sciencey equations and citations. Thus, the three aren't always mutually exclusive. On the other hand, a purely science based query will... $\endgroup$
    – elemtilas
    Oct 11, 2021 at 13:14
  • $\begingroup$ (cont) ...not involve magic or fictional science at all, and won't ask for numbers and citations. The hard science tag necessitates the science-based tag, rather than excludes it, because the citations and numbers all involve real world science. The situation is more of a spectrum from the most made up to the most rigorously studied & documented. $\endgroup$
    – elemtilas
    Oct 11, 2021 at 13:16
  • $\begingroup$ @AdrianColomitchi "does not require citations" means "answers without citations are OK" It does not mean that answers with citations are forbidden. $\endgroup$
    – sphennings
    Oct 11, 2021 at 13:24
  • $\begingroup$ @elemtilas As written from a usage perspective they are used to set out a minimum level of acceptable citations. However you are right right from a content perspective hs is contained within sb. We have lots of tags that are contained wholely within others and we don't seek to merge them. (biochemistry, is a strict subset of chemistry, yet both tags have value) $\endgroup$
    – sphennings
    Oct 11, 2021 at 13:31
  • $\begingroup$ Hey! Do you guys mean that making hard-science and science-based as mutually exclusive does not bring any benefit for the good functioning of the WB community in itself, and these tags are useful only to express the expectations of the questioner on the format of the answer? And that punishing a user (and throwing away a question) just because of redundantly expressing both tags is not geared to improve the quality of answers nor the fluidity of interaction between the questioner and those providing the answers? $\endgroup$ Oct 11, 2021 at 13:45
  • $\begingroup$ What do you mean punishing a user and throwing away a question? $\endgroup$
    – sphennings
    Oct 11, 2021 at 13:48
  • $\begingroup$ @sphennings "throwing away a question" - closing a question for reasons that don't bring a benefit for the community. "Punishing the user" - depriving the user of any potential answers that are impossible to post after the question is closed. $\endgroup$ Oct 11, 2021 at 14:28
  • $\begingroup$ I believe your post had other issues associated with it besides the tags. If it's just a tag issue, it's a very minor edit to change the tags, and the post will be added to the reopen review queue. If more substantial edits are required then you can use the same process to resolve the concerns and get the question reviewed and reopened. $\endgroup$
    – sphennings
    Oct 11, 2021 at 14:46

It appears this issue is easily repaired by removing a single word from the tag summary and a sentence from the tag wiki

First of all, it is critical to understand the purpose of tags. They do NOT scope the question. They scope the answers. Yes, I get the fact that people will commonly use them from the perspective of "This is a question about ," but that doesn't change the fact that the point of the tag is to indicate that the OP wants the answers to reflect vs. .

Correct tag use is important and expected. Questions do get closed due to inappropriate tag use. We actually expect people to read the tag wikis. From the wiki we read:

If you want scientifically correct answers but don't need scientific citations, consider using instead. Do not use on a question that has ; it is redundant. However, do not remove from a question that has both and . Instead remove , because holds answers to an even higher standard.

That's awfully clear. I frankly don't understand how to misinterpret "Do not use on a question that has ; it is redundant." However, whoever in the distant past added that last sentence wasn't thinking. In fact, I consider it pretty bad advice. Regardless of my opinion, though, it's unnecessary advice.

So I propose that the sentence be removed.

However, do not remove from a question that has both and . Instead remove , because holds answers to an even higher standard.

Next, changing one word in the summary

Just to make a point, the wiki states...

If you need scientific citations in answers, use the tag instead.

...and that's pretty clear to me. The word "instead" in English implies mutual exclusivity. If we need an actual statement that uses the phrase "mutually exclusive," I have no problem adding it (we've been using these tags this way for years... why is it suddenly unclear?)

The real problem appears to come from the summary. It's the word "hard."

For questions that require answers based on hard science, not magic or pseudo-science, but do not require scientific citations. Contrast with the hard-science and reality-check tags. Do not use this tag as the only tag on a question because it describes how the question should be answered, not the topic.

And there's our problem. appears to be about "hard science" and appears to be about "hard science." Worse, still, is that too many new users don't bother reading the wikis and think refers to the story genre "hard science" and not what we claim... but that's another issue for another day.

But the world does like to create differences. We have "hard science" and "pseudo science" and "junk science" and all kinds of "science." In reality. There's just "science." Anything not science in the Real World is pretension and in Worldbuilding is with the exception of speculative science (something "sciency" that's based on science but doesn't exist in science and can't actually be proven as science, which is what I thought the tag should be used for, but it isn't, and that's a whomping huge hole in our methodology....).

But, to make a long story short, removing the word "hard" from the summary solves that half of the problem.


So... Remove one useless sentence from the wiki and one unnecessary word from the summary and this problem is solved, right?

  • $\begingroup$ Sounds like a good basis so far. I'll have some suggestions to adjust the description of the tags as they show in popups, visiting the wiki to get the essential nitty-gritty is a friction that can be lowered. But I need some sleep first. $\endgroup$ Oct 11, 2021 at 15:13
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    $\begingroup$ @AdrianColomitchi I wouldn't recommend burning too much time on this. The science-based, hard-science, science-fiction, and reality-check tags all need to be reviewed in the context of a very high-level perspective to fix the hole I mentioned and a number of other things. It's a pretty big project that would span several Meta posts but hasn't been such a big issue that we've gotten around to it. Remember, we've used these tags the way we do for years.... $\endgroup$
    – JBH
    Oct 11, 2021 at 15:43
  • $\begingroup$ @JoinJBHonCodidact I wonder... Where did you see that tags scope specifically answers 🐸? On the help page, they are much more focused on telling they "describe the topic of the question", for the purpose of helping answerers and readers finding them. Nowhere it is said that they directly scope answers as opposed to questions (emphasis on "directly"). $\endgroup$ Oct 13, 2021 at 11:42
  • $\begingroup$ @Tortliena Over the years it's been brought up in commentary here and on Meta Stack Exchange. The issue is specifically relevant with the tags in question for this post because they were intentionally designed to scope the answers and say as much in their wikis. $\endgroup$
    – JBH
    Oct 13, 2021 at 16:06
  • $\begingroup$ @JoinJBHonCodidact I'll get a look at it myself there, then ;). $\endgroup$ Oct 13, 2021 at 17:31

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