I'm personally a bit ambivalent about questions like this:

Part of me thinks, "Who cares? The earth does have water." But it seems people like asking these questions, and perhaps the answers are relevant to planetary geophysics, or are just interesting to think about.

Counterfactual vs hypothetical

Are they different from (though clearly related to) 'hypothetical' questions, which have been discussed before? I think they're a bit different, though I'm not sure I could articulate the difference... maybe 'hypothetical questions' are about the future, but 'counterfactual' ones are about the past? Or something.

If they're not different, then I guess we should sticking the hypothetical tag on them... or start closing them, because the consensus there seemed to be to disallow them.

If they are different, then do we like or not like? If we like, then do we need a counterfactual tag?

Interestingly, they seem to be banned on History Stack Exchange, and people get a bit cheesed off about them.


2 Answers 2


I think those are different from the purely hypothetical questions because planetary science is on-topic. While the example questions are hypothetical from the context of earth, they could be re-framed to ask the same questions about wind or plate tectonics on any rocky planet. From that standpoint I don't think we should close them just because they pose the question about earth if it would have been otherwise ok to ask about e.g. mars.

Perhaps what should done is to edit those questions to frame them as asking about the specific dynamic processes on a suitable planet. For example instead of "wind on earth without water" it could be framed as "wind on a rocky, waterless planet with an atmosphere" or something like that.

I will, however, qualify that the example planet should be a reasonable choice. If the question was "wind on some kind of planet that is non-physical" I would put that squarely into hypothetical territory.


Old planetary scientist here.

Back in the 50's and 60's, when we knew so little about other planets, we actual did ask ourselves those kinds of Q's as a way to think about other planets. Then we knew more and were able to fit our descriptions around the theories being developed or established. We understand planets in themselves now, rather than as strange Earths.

Or do we?

We are now in the exciting, and very confusing, phase of exo-planetary discovery. And how do you suppose we talk and think about them? Superearths, waterworlds, hot Jupiters, warm Titans, sooty Neptunes. We are back to struggling through metaphors and hypotheticals.

We need to remember beginners here are still in the Aristotelian physics phase of learning earth and planetary science. We may think of their Q's as nonsensical, not relating to how science is done, but in fact this is exactly how science is done when one is at the very beginning of understanding a subject of study.

We, hrrrrmph hrrrrmph, serious students of established science are pretentious enough to show disdain for the struggle. But put us in front of a completely novel and unexpected phenomenon, like dark matter and hot Jupiters were a mere decade ago, and we allegedly very smart people will postulate in the exact same way.


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