# When are questions with multiple different possible answers good?

It is well known that we do not encourage/allow questions that solicit open-ended discussions or that can only be answered by providing personal opinions, etc. However, at least to me, it seems a bit unclear as to what is the policy around questions that are not ill-defined (in that there is a well-defined criterion for what would be a correct answer and what would be an incorrect answer) but still, there are multiple possible answers (and not just multiple possible ways to answer which is, of course, always the case). Sometimes, such questions can fall under the "big list" question category. But, other times, it is not so clear because the question may not have been asked in the spirit of a big list question owing to there being no way for the OP to know if answering it entails a list of things or just a single thing. There is a somewhat relevant discussion in Good list, bad list but it is more geared towards book recommendations.

A question asking for the experimental evidence for a prediction or a law can often fall under the category of questions that I am describing. This example, Experimental evidence for $F=\frac{dp}{dt}$ is what led to this meta question. And an example of an extremely well-received question of the kind I am describing is What experiment would disprove string theory? where the highest voted and accepted answer includes a list of experiments that would disprove string theory before going into the more general conceptual discussion. Perhaps that is the correct criterion? That answering the question might involve lists but if it also has a genuine place for broader conceptual clarification then the question is a healthy question?

Perhaps that is the correct criterion? That answering the question might involve lists but if it also has a genuine place for broader conceptual clarification then the question is a healthy question?

I think so.

Let's suppose the purpose of Physics SE is to accumulate a database of questions/answers that are helpful to people who are trying to understand physics, and that are likely to be found by those people in a search. The keywords here are trying to understand and likely to be found.

If that's the purpose, then maybe that should be the overriding criterion in cases where other guildelines are ambiguous. Maybe even in cases where other guidelines are not ambiguous.

The question "What experiment would disprove string theory?" is one that resonates with many people, not so much because they want a Big List, but because they want to know whether or not string theory is good science. That's exactly the motivation given in the body of the question. For that reason, having this question/answer(s) in the database is likely to benefit many people who are trying to understand physics.

The question "Experimental evidence for $$F=dp/dt$$" might be more elementary, but the level of the question is not so important, in my opinion. The overriding criterion is: will people who are trying to understand physics find this question in a search and benefit (gain understanding) from its answers? Whether the answer is yes or no, I think this is the right criterion.

To be fair, I confess that I haven't always prioritized this criterion as consistently as I should. The fact that I posted this answer on Meta will help me remember to do that.