> I am not aware of anything even on the fringes of science that would permit a superior communication technology over EM

In another comment you mentioned things such as gravity waves, neutrinos, etc. You also mentioned that these things are far more expensive to generate than EM. I think those particular facts are "engineering problems to be solved" rather than just fundamental laws, yea? I never fired off a neutrino, I know you need a sun or a particle accelerator to do it, so I get why it's considered expensive, but is that inherent?

They didn't think particles could be proven as indistinguishable until they realize the laws of physics depend on it and therefore you could test for it.

I don't think it's a comparable flight of fancy to ask about whether there's a way you could detect unaccounted-for energy within some region that isn't one of the usual suspects.

Yes, there's always the "what if our understanding is completely broken", but your comments here feel way too uncharitable and dismissive, willing to equate the two kinds of questions.

"I don't think it's a comparable flight of fancy to ask about whether there's a way you could detect unaccounted-for energy within some region that isn't one of the usual suspects."

I gave you one interpretation of what I mean by flight of fancy already, which doesn't match what you seem to be reading it as.

The problem with the question about where stuff could be hiding is that, as I said, I'm as up-to-date as you can expect to be on this stuff for a layman, and I'm not aware of any "unaccounted for" energy that might be useful for communication. It is not known whether "dark energy" is simply a violation of conservation or if it is perhaps coming from somewhere else, but it doesn't seem useful for communication either way, and I'm not aware of any other places where energy is not accounted for.

Indeed, note all the modern articles are discussing how we are in precisely the opposite situation, and that's the problem for physicists today, that we do seem to have all the energy accounted for and there's nowhere else for physics to be hiding, which is a massive problem because we know we're not done yet.

At the moment, hypotheses about such things would be based on zero evidence. Again, I'm pretty comfortable calling that "flight of fancy". Maybe someday one of them will be correct. But the vast, vast majority of "flights of fancy" are not. Like that stupid "first they laugh at you, then they fight you, then you win" quote that everybody reads as if it's some sort of inevitability. In reality, what happens is that "they laugh at you, end of story" is the dominant case. There is no path of causality where simply because they're laughing at you you're inevitably on the path to winning. The ability to imagine in an incredibly hand-waving way that maybe something exists is not the slightest bit of evidence that it does.

> The problem with the question about where stuff could be hiding is that, as I said, I'm as up-to-date as you can expect to be on this stuff for a layman, and I'm not aware of any "unaccounted for" energy that might be useful for communication.

I'm aware you're not, and explained an example of a non-trivial, responsive answer which would differentiate between the "unknown" and "reasonable to rule out" case. "No, there is a way to measure the total amount of energy flux, across all sources, through a region and it rules out the possibility of undiscovered forms of energy passing through us without us knowing."

Similarly, if someone asked about whether Conservation of Momentum could be wrong, I would point out Noether's Theorem and how it falls out as a result of linear translational invariance of the laws of physics and thus has a higher barrier to disprove and what that would have to look like. I wouldn't just call their question a flight of fancy.

No one deserves ridicule for curiosity or asking which state the science is currently in.

All of your responses just come off to me as attempts to ridicule legitimate questions, so I don't feel comfortable engaging further.

>What else would a flight of fancy be other than imagining something that we currently have absolutely zero evidence for?

Exactly, but that was spirit of OP's question.

I do think that the fact that we can rewind our own history and find examples of technologies that were unimaginable at some more distant point in our history as something more than "absolutely no evidence."

> What else would a flight of fancy be other than imagining something that we currently have absolutely zero evidence for?

It would be a flight of fancy to argue for or imagine a specific one, but it's not a flight of fancy to say, "hey, there's probably forces and particles out there we don't know about or understand yet". Hell, it would be obscenely arrogant not to acknowledge that.

I'm going to take a stab at phrasing the question in terms of a simple yes or no answer. Do you believe it is possible that there exists a physical phenomena that, if described to you right now, would clearly be a "flight of fancy", however would in fact turn out to be real? Note I'm not asking you to state what that phenomena is or to "imagine" anything at all. Just that it can be ruled out that anything is really left to be discovered. Just as though it were the year 1500 and someone described radio waves to you. Because if you say no, that seems awfully confident that science has basically discovered every significant aspect of physical reality, it's just the small details left. The same attutide would have existed hundreds of years ago.

"Do you believe it is possible that there exists a physical phenomena that, if described to you right now, would clearly be a "flight of fancy", however would in fact turn out to be real?"

Yes, of course.

I think those of you who are finding your feathers ruffled need to go back to the initial post. The question is, do you want to answer the question based on current science, or do you want to imagine whatever you want to be the case? Both are valid options. But pick one. You do nobody any favors when you try to blurrily flick back and forth on a whim.

And the truth is, if you are going to just imagine whatever you like, there isn't much interesting to say about it precisely because anything could be true. Could aliens be communicating by getting high on DMT and have found a way to use DMT entities to transmit real, useful messages? Sure, whynot, but what's there to say about that?

By contrast, we can discuss what real science currently has to say about what aliens may be doing. Current science says there's not much reason to expect anything but EM. If you find that unfortunate somehow, that's a psychological thing, not a scientific thing.

Or, at least, we COULD discuss what real science has to say about it if people didn't immediately pop up with the equivalent of "But what about DMT-entity-based communication???!?" every single time.

Good answer, except for the last part. I think there is not much reason to expect we will detect aliens using anything other than EM, because that is all we know. But for all we know they could be sending messages to other galxies by communicating with the outside makers of the AI Elon Musk thinks created the universe.

Your turn: Yes or no, is "communicating with the outside makers of the AI Elon Musk thinks created the universe" something we have zero evidence for? Is that not reasonably categorized as a "flight of fancy"?

If yes, why do you expect to be able to say anything sensible about it? And why are we apparently obligated to discuss it despite explicitly setting up a premise of "let's discuss things using the physics we know?"

This is failing on the most basic level of philosophical discussion here. We are allowed to discuss "If X, then Y" without being obligated to also discuss "if ~X", nor is it a reasonable philosophical objection to "If X, then Y" to say "Well, what if not X?" It is a reasonable objection to disprove X and prove the whole "If X, then Y" conversation is thereby vacuous, but if you can disprove science as it stands today, this is hardly the place to do it.

(I'd also point out I did discuss "what if ~X" even so. It's just that if we're going to assume anything we like, we can get any answer we like. There's a profound sense in which there isn't much to say at that point.)

> Your turn: Yes or no, is "communicating with the outside makers of the AI Elon Musk thinks created the universe" something we have zero evidence for? Is that not reasonably categorized as a "flight of fancy"?

absolutely

> If yes, why do you expect to be able to say anything sensible about it?

I said somehting I think was sensible, which is that we have no way of knowing such a thing.

> And why are we apparently obligated to discuss it despite explicitly setting up a premise of "let's discuss things using the physics we know?"

We are not. We are obligated to acknowledge we don't know everything, which you admitted to by stating that sure, something that's a flight of fancy today could someday prove to be true, hence, there are possibly things we don't know. We of course cannot do anything with that, because we have no way to know.

> This is failing on the most basic level of philosophical discussion here. We are allowed to discuss "If X, then Y" without being obligated to also discuss "if ~X", nor is it a reasonable philosophical objection to "If X, then Y" to say "Well, what if not X?" It is a reasonable objection to disprove X and prove the whole "If X, then Y" conversation is thereby vacuous, but if you can disprove science as it stands today, this is hardly the place to do it.

all I wanted to state was that there may be things that prove to be true which if we were to hear them today, we would only be able to conclude they are flights of fancy and nothing more. and we agreed. I'm not attempting to make the "how do you know X doesn't exist?" argument because there's no X that has been suggested except for an intentionally ridiculous example. I'm more making a comment on what seemed to be your absolute certainty that electromagnetic energy is definitely the only way any intelligent life form would ever communicate across distances, science has successfully and provably ruled out any other possibility.

From Littlewood's Miscellany:

"Schoolmaster: 'Suppose x is the number of sheep in the problem.' Pupil: 'But, Sir, suppose x is not the number of sheep.' (I asked Prof. Wittgenstein was this not a profound philosophical joke, and he said it was.)"