Can multiple people hallucinate the same thing at the same time ?

[Jehanne]

Well, it's not clear that you understood my point, but regardless, let's cut to the chase: what do you think you should conclude if there is no explanation?

Well exactly that , that there is no current explanation and that we can hope that one day science will have the answer , until then we can only say that we don't know ( we can guess based on logic and reason , but it's still just guesswork ).

Why do you think the burden of proof exists at all to explain anything that is outside the realm of observation and/or experiment? Besides, there are literally thousands of controlled psychological experiments that offer purely naturalistic explanations for hallucinations, both individual and collective experiences.