Lately we have seen a few open-ended questions presenting ideas that the poster thinks is a novel concept, but which are clearly impractical to people with modest backgrounds in engineering. The latest is a question about a concept for a perpetual motion machine, and before that we had one about storing houseboats in floodplanes.

Sometimes these questions are malformed and already violate one of our existing rules. That said, as long as the question is well-formed (with a clear question like "is this feasible?") it would be possible for us to answer and walk the questioner through the reasons their concept isn't already implemented and wouldn't be practical or possible. As a policy, should we try to answer these questions in a way that is clear to the questioner?

On one hand, it's an opportunity to present a concept that we probably haven't explained in a Q&A, and there is potential to recruit a new member with a positive experience. On the other hand, these kinds of relatively outlandish questions might prevent engineers with more to contribute from joining our community, and these questions tend to decrease the signal to noise ratio. Another problem is that sometimes the people who ask these questions are very argumentative about their ideas, so answers may become less about explaining a concept, and more about convincing people that the basic rules of physics apply.

Hopefully we can develop a community guideline for how to handle these questions, and if we don't accept them, a clear test for what defines these misguided novel ideas.

  • $\begingroup$ Can you add links to the relevant questions to make it easier for people to find the specific examples? $\endgroup$ Jun 13, 2015 at 17:45
  • $\begingroup$ I added one for the houseboat question, I believe the perpetual motion question has been deleted. It described using a heat pump to power a generator, and then the generator to power the heat pump. $\endgroup$
    – Ethan48
    Jun 13, 2015 at 17:53
  • $\begingroup$ Here's another recent post that may show a better side of this sort of question. $\endgroup$
    – Air
    Jun 15, 2015 at 17:24
  • $\begingroup$ @Air That was my hope when I saw it, but looking at the two answers so far I feel like it's actually proving the opposite point. The answers are largely speculation with very light grounding in engineering principles. It's not my area of expertise, so it's hard for me to know if the idea is plausible or not, but it doesn't feel well thought out or explained. $\endgroup$
    – Ethan48
    Jun 15, 2015 at 18:02
  • 1
    $\begingroup$ @Ethan48 Poor answers only become a problem when they outscore or replace better answers, so we'll have to wait and see. It's very difficult for me to assess, not having a lot of expertise specific to that problem domain, whether a good answer is impossible or merely has yet to arrive. $\endgroup$
    – Air
    Jun 15, 2015 at 18:13

2 Answers 2


This is a tough one, and I've been thinking about this myself too. I don't want more questions like the house boat one, but it wasn't obvious at first why.

No, we don't want "Why doesn't everyone <insert crazy idea>?" questions

The problem with these types of question are usually:

  1. They are open ended, or usually "too broad" in SE-speak.

  2. They are asked by someone that doesn't understand enough of the relevant technology and engineering to properly understand answers.

  3. The asker has usually made up his mind already and is expecting us to marvel at his brilliance.

  4. Since the asker is already convinced (see point 3), reasoned explanations will be met with arguments.

  5. Asking "Why don't we...?" is asking the wrong thing in the first place. The implication is we're all being stupid and this guy is the only one in the world to whom it occured to do this. Screw that.

If done properly "Why doesn't xxx work?", "What is the fault with xxx?" can be acceptable.

The big difference here is that the asker realizes there is probably a very good reason why his idea won't work. He's not implying we're all stupid. His attitude demonstrates that he will be willing to listen and is genuinely trying to see the flaw in his thinking. This is a teachable moment that would be a shame to pass up.


The boundary between the two cases above will always be gray, and this will always be a judgement call. However, some pre-requisites for a acceptable question of this type include:

  1. The asker must acknoledge that the idea is probably unworkable.

  2. The attitude must be clearly about wanting to truly understand why not, as apposed to the rhetorical "why", as in "Why are you all so stupid?".

  3. It absolutely must not reference any nonsense snake-oil science websites, quotes, etc as corroborating theory. This should be a close reason on its own.

  • $\begingroup$ I'm skeptical of using the tone/attitude of a question to decide if it's allowable or not. I think there is real risk that such a rule would in practice bias our site against people on the basis of english skill, local cultural norms, age, etc. I'm much more interested in discussing the content of the question and whether or not it can yield a useful answer. $\endgroup$
    – Ethan48
    Jun 18, 2015 at 19:03
  • $\begingroup$ @Ethan: Good point that it's subjective. On the other hand, first we already require a minimum proficiency with English. Second, you don't justify why there is anything wrong with being biased against those that can't or won't communicate according to the norms here. Poor writing is annoying to read and devalues the site, so one could argue that discouraging those that practise it is good for the site. $\endgroup$ Jun 18, 2015 at 23:26

I have a few thoughts about why these types of questions don't/won't work here. Each of these could be a separate answer, but I am combining them all together. There seems to be a related underlying thread to them.

No, They are at best naive design questions.

There has been some discussion about whether the term "Naive Design Question" is a good title, but the discussion is still valid.

No, They end up being a moving target.

The novel idea may sound like a good one at first, but our site has enough users with varying experience to sort out the major problems. Once these problems are brought up, the question changes. This creates a moving target for users who may want to answer the question. After an answer is invalidated multiple times by changes to the question, frustration sets in for the user.

No, This site is not an open forum for discussion. It is for questions and answers.

The questioner usually is looking for validation that their idea is a good one. That is not what this site is for. The accepted answer should not be, "Yes, that is a good idea!"

We also do not want answers or comments that say, "Your idea would be better if..." This creates a moving target.

No, Solid, real questions are what we should hope for.

We have drawn visitors to our site through the "I've always wondered.." questions, but we should also want the questions that professional practitioners and students have.


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