>>12091571By doing it.
If there's some entanglement/higher dimensional linkage for consciousness, then creating a copy should instantaneously kill the original.
If it makes a branch, then you just have to ask one of the copied observers if they can perceive what the other one can.
If they can not perceive the same information, while separate... Then boom, you have your answer.
Elsewise, we don't know yet.
