I find this problem reoccurring in many skepticism-based (or just skepticism-flavored) web forums or generally, any discussions. In the most basic (and most annoying) form, it goes like this. Someone says something, or asks something, and then they are required to define the words they used. One very common example is:

  • Q: Do UFOs exist?
  • A(1): Define 'UFOs'
  • A(2): Ofcourse the do! (smartass smile) (after a supposedly meaningful silence): surely there must be some objects that fly and were also unidentified at least by some!
  • A(3): Define 'exist' (this case is nearly pathological, but it does happen in real life!)

All right. When someone asks about UFO they most certainly mean extraterrestrial visitors. Flavors may be different, but nobody means to ask this way about a hot air balloon which just happened to be unrecognized by your Aunt Marry. Everybody knows balloons exist, and that they sometimes may get unrecognized. If someone doubts that unrecognized part, they surely ask "can balloons get unrecognized or confused with something", not "Do UFOs exist".

Lets go to real examples from this website.

  • Q: Is it possible to die instantly?
  • Comment: define 'instantly'.

Geez. Everybody knows, what 'instantly' means. If asker had in mind some specific timespan which may also fall into the 'instantly' category, he would have asked just that: Is it possible to die within 3 milliseconds? Also, a proper answer should include scientific data, and scientific data is always specific enough to answer this kind of question whatever definition of 'instantly' asker had in mind, 2 seconds or half millisecond.

Another one.

  • Q: Can an average person be involuntarily hypnotised?
  • Comment: define 'hypnotised'
  • Answer: define 'involuntarily'

Answer is summed up by me. Real answer included thoughts about what free will is, if it exists at all, usual free will vs determinism BS, in other words. Which is completely irrelevant in this case. The asker updated his question with an example of what he considered 'hypnotized', a very good example I might add, but this is the kind of example 99.99999% of people would give you. Everybody knows what the common definition of 'hypnotized' is.

Where is the problem?

  • Definitions hardly help. They just use more words, someone might in turn ask to define them, too, ad infinitum.
  • Sometimes it's hard to find words to define something, even if you know what you mean very clearly.
  • Sometimes it looks really silly and may scare common people away. People may think you are nitpicking, or making fun of them, or that something is wrong with you.
  • It can be a flame bait, a start of a useless debate of what the real definition of x is, drawing attention away from the question. Happens in forums like, about everytime.

What I suggest

Now lets get this out of the way first. I am not saying that every question must be fine as is. Or that you should never ask for clarification or even definition, especially if the term is unheard of, or the question is really vague, etc. But, points to consider:

  • Does definition really matter? (example: does soul exist? - No. I don't care if you are talking about a soul in Hinduism sense, or a soul in Christian sense, or a soul in your personal sense, answer is the same.)
  • Can the question be answered clearly enough without knowing the exact definition?
  • Can you provide an answer for every common definition? (Example: is hypnosis real? short answer: depends. Movie-style or this-website-here style hypnosis helping enlarge your penis is BS [source], [source]. However it is possible to influence human mind in certain ways using certain chemicals, to which professionals refer as 'hypnosis' too [source][source][source])
  • What the asker is most likely to have in mind? (See example with UFOs above)
  • Can you answer it in the way that satisfies whatever definition? (i.e. is LSD like bad for your health? a: known LSD effects on your health are as follows: [list...] [source][source]

I am only suggesting that we should try to avoid asking for definitions as much as possible. Yes there's no such problem here yet, compared to some skeptics forums I used to read, but since I see the first signs of it, I don't wanna wait till it blossoms ;)

What do you think. Lets discuss.

  • 5
    +1,000,0000. Wow, thank goodness someone articulated this instead of me.
    – Uticensis
    Commented Mar 31, 2011 at 22:39
  • If you think a comment is just noise, just flag it. If enough community members do the same, it will be automatically deleted.
    – Mad Scientist Mod
    Commented Apr 1, 2011 at 10:18
  • 13
    Define "common sense".
    – Shog9
    Commented Apr 1, 2011 at 14:28
  • I flagged your comment - question as a spam. If you don't know, what common sense is, you should try asking in english.stackexchange.com or using dictionary.
    – user288
    Commented Apr 1, 2011 at 15:06
  • 6
    @Sejanus: I don't trust dictionaries - they frequently list multiple, conflicting definitions for words, a sure indicator of a cowardly attempt at obtaining the veneer of "objectivity" by slavishly presenting all "sides" regardless of merit. (and yes, this is a joke - happy April 1st, Sejanus!)
    – Shog9
    Commented Apr 1, 2011 at 15:33
  • 3
    @Sejanus 'Common sense' varies from person to person. For a person living in a cave, it's 'common sense' to use the skins from a rabbit for clothes/etc. (There's probably a better example, but I don't live in a cave.) It's 'common sense' not to light the fire in front of the alpha male. (Maybe the alpha male has banned fires.) For you, it's 'common sense' that 1+1=2. It's 'common sense' to look both ways before crossing the street. You may not know what's 'common sense' for cave people, as they may not know your type of 'common sense'. IMHO, 'common sense' doesn't really 'exist'. Commented Apr 18, 2011 at 23:15
  • @Sejanus Of course, my last comment only proves your point (sort of). :) Commented Apr 18, 2011 at 23:23
  • 1
    how many cavemen visited this site lately?
    – user288
    Commented Apr 19, 2011 at 4:40

6 Answers 6


I see this as one of those cases where commenters and answerers have a good point but are approaching it in an unhelpful way.

Imagine the opposite case, which IMHO is worse:

  • Q: Is it possible to die instantly?
  • Answer: Yes, of course, we see it all the time in the news.
  • Comment: No, those people are not dying instantly
  • Comment: Yes, they are
  • Comment: No, they're not

So when you say,

Definitions hardly help. They just use more words, someone might in turn ask to define them, too, ad infinitum.

Definitions form an essential common ground of agreement from which to move forward on. No answer can be definitive unless it is beyond argument, agreed upon by the facts and the researchers. And no answer can be beyond argument without agreement on definitions.

Put another way, if I say:

A + B = 42.

What if we don't agree on what A and B are? With numbers it's simple. In language, it's not so easy. Definitions quickly become complicated. You are asking for "common sense". Yes, there are some words which have a single unquestionable meaning. "Involuntarily" might be one of them.

"Hypnotism" however, is not - there are a large number of entertainers who call themselves "hypnotists" who perform "hypnotism" and the audience believes it to be one thing while it's actually not. I've never been hypnotized so I would be among the worst to guess at what it is or isn't.

Even one person's definition of "common sense" is entirely different from another's.

The real problem...

Isn't that we are ignoring "common sense", it's that a curt "Define hypnotism" comment, (or worse, answer) isn't helpful. In this situation, I think one of two things is constructive:

  1. If you can't help define the answer, but you feel the concept is too vague to get an unqualified, definitive answer, say "Hypnotism is a commonly misunderstood concept - the vast majority of people believe it to be a mystical trance, but this is probably not a constructive definition to work from. It might help if the question or an answer can clarify this."

  2. If you are going to answer, remember to include information about common misunderstandings, or even disputed definitions, and point to references on the topic of the definitions. Then, use those definitions to form the basis of your answer.

  • The problem with your example is that the answers and comments are not good despite the question being supposedly vague. Whether there's a definition or not it wouldn't matter in this case, answers were not good. Proper answers should point to scientific research showing death times.
    – user288
    Commented Apr 1, 2011 at 5:00

Common sense is the collection of prejudices acquired by age eighteen. Albert Einstein

Being a good skeptic is about being skeptical of common sense ideas. If an idea isn't backed by empiric evidence it should be discarded.

Everybody knows what the common definition of 'hypnotized' is.

The idea of hypnosis that exists in popular culture doesn't describe what hypnotists do in the real world. If you want to understand what hypnotists can do in the real world, you should let go of the way hypnosis is portrayed in popular culture.

There no way to answer Can an average person be involuntarily hypnotised? accurately without first clearing the confusion that's inherent in the terms that are used.

The existence of God was a long time considered to be common sense. A week ago I was ill. I took homeopathic "medicine" and now I'm healthy. It's common sense that the "medicine" helped me. You can't be a good skeptic without questioning ideas that you consider to be common sense but which aren't based on empiric evidence.

  • 1
    Like I said in a comment above, I am talking about using common sense only as far as understanding the question goes. It should not replace the proper answer by any means.
    – user288
    Commented Apr 5, 2011 at 18:26
  • 1
    I agree with user288. This answer is just a straw man argument
    – Casebash
    Commented Feb 13, 2012 at 21:30

I think the right way to approach any question where you see a vague description is to ask yourself, "How many different valid questions can I think of, using different meanings of that word?"

By "valid question", I mean:

A valid question is a question that can be answered by facts or by applying knowledge not common to most human beings. It is a question whose answers will be informative and interesting, not self-evident.

There are two possible answers to that question, each call for a different course of action.

If, while there are many possible ways to interpret the question, there is only one interpretation that leads to an interesting question, then the right course of action is to edit the question's body to be clearer.

If it's unclear what is being asked, if you can think of a few interesting interpretation of the question, then leave a comment to ask the user to clarify what he means. Then, vote to close the question as "not a real question" due to its vagueness.


Going through your examples..."Do UFOs exist?" is badly phrased to begin with, and probably should be answered with a comment "Do you mean something like whether there are extraterrestrials on Earth?" (Of course, there's no way to tell if they aren't on Earth, so it would be a bad question here anyway, although something like "X says there are intelligent aliens on Earth in book Y. How credible is this?" would fit nicely.)

Instant death: the definition of "instant" is critical. I can't die in a picosecond, since that's about the length of time light takes to travel 0.3 millimeters, and nothing can propagate faster than that. I can certainly die in less than a second (from nuclear attack, say), and that might well qualify. Moreover, if we're talking about how fast it takes to die, the exact definition of "death" matters. The comments weren't real helpful, but the question really can't be answered as asked.

Involuntary hypnosis: this is a real problem, and does depend vitally on "hypnosis" and "involuntarily". The common sense definition of "hypnosis" is not useful in answering questions, since it's a very vague concept that includes things that really aren't there. "Involuntarily" also has different possible meanings. Refining that question is hard, and although the comments weren't particularly helpful I don't know how they could have been all that much better.


I strongly agree with Sejanus's guidelines. The purpose of this site is to provide answers to questions that people want. When someone asks whether it is possible to die instantly, they don't want to have to define exactly how quick instantly is. We also shouldn't expect them to already know about all the different kinds of death (clinical death, brain death, ect.) or suggest they limit the question to one particular type of death. Then they'd have to ask 3 or 4 very similar questions to actually get something useful and each question would be too specific for most people who stumble onto them.

Some questions are definitely too vague. Some of these are obviously so and should be closed outright. Other questions may seem answerable, but actually end up being much more complicated than expected. For these questions, the best answer may be one that gives a general overview of the issues and explains why the issue is too difficult to resolve as is or is subjective.

I think when asking for clarification, it is important to not just ask for a term to be defined, but to give some idea of the different ways you think it can be interpreted. For example, when I was first asked to explain hypnosis, I thought that it was adding a definition would be pointless, but after I received more detail, I realised that a definition would actually improve the question.


I don't think this is so much an issue about common-sense (which I do think is incompatible with skepticism) as much as one of accepting common word-usage.

When I say "blue" and someone responds "how do you know that the blue you mean, is the same as the blue I mean" I would refer them to discuss that on http://philosophy.stackexchange.com or perhaps http://english.stackexchange.com. I very well don't mean green, purple or car, and I'm pretty sure there's a definition somewhere that refers to the visible light spectrum for those that are unsure what the meaning is.

I also think it's really unhelpful to just plain write "Define UFO" when they should be adding something of value like: "Do you mean unidentified (extra-terrestrial) flying objects?" or better yet, edit the post.

I find it slightly perplexing that people seem to be so unwilling to draw assumptions (and then declare them). Instead they go on an easy path of offering unhelpful critique, which seem to cause more noise than signal.

Things like these always remind me of a discussion I had with a friend that told me the word irony didn't have the definition of present-day irony in ancient Greece (that supposedly the word originated from), and so he downright refused to accept me using it with the present-day definition unless I declared so beforehand. I just found that irony not having the definition of irony is ironical.

  • What I meant by common sense, is that using common sense helps with understanding what the asker has in mind; and also helps to word your answer properly instead of just saying "define X" and be done with that. I am by no means suggesting that common sense should serve as an answer by itself, i.e. "No, rocks cannot fall out of the sky because it makes no sense" ;)
    – user288
    Commented Apr 1, 2011 at 11:04

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