[qwerty456127]

It seems obvious they probably don't exist and it's hardly possible to prove they do. But if they did (proving they don't exist seems equally impossible to me), I could only imagine they would communicate the way I describe.

Nevertheless it indeed seems a curious exercise to invent a framework for meaningful communication to be logically possible over a channel of such a nature keeping its fuzziness in mind.

[mjburgess]

Yes, but the only reason you can imagine it this way is that the many other possible ways are ruled out by the fact we do not observe them.

There is no purely logical reason the universe couldn't be such that a person's soul is capable of moving the air, such that they can actually speak.

[qwerty456127]

I instinctively try to make the least bald assumption possible. Of course, as we exercise unconstrained imagination, we could imagine a ghost being so mighty it would materialize beautiful LaTeX documents right on our hard drives manipulating magnetic particles on them. Nevertheless, if I forget about the doubt in ghosts existing at all for sake of fun or whatever, the next doubt I have is they can manipulate the matters of material world with ease and precision - even if they could manifest a blow of a wind it would probably be hard for them to manipulate it precisely enough to produce continuous ineligible speech.