Even Max Tegmark suggested about the multiverse concept: “Is there a copy of you reading this article?”
IMHO, Inside CP symmetric Multiverse concept the building blocks of the brain and the foundations of quantum mechanics should have a common way to use the observer function of entanglement between CP symmetrical systems at long multiversal distance.
Therefore I suggest :
A Testable CP Symmetric Multiverse Model by Extended Experiments, Done by the Late Benjamin Libet in 1964.
Benjamin Libet measured two different electric Readiness Potentials time profiles called RPI and RPII. to perform a volitional act, in the brains of his students related to the Time of Conscious Awareness (TCA) of that act, which appeared to come about 400 m.sec behind the RP I or RPII.
All “volitional acts” were in principle based on the free choice to press an electric switch button.
The results of this experiment gives still an ongoing debate in the broad layers of the scientific community, because the results are still (also in recent experiments) in firm contrast with the expected idea of free will and causality.
However I woud propose the seemingly absurd but constructive possibility that we are not alone for decision making if we live inside a Charge/Parity (CP) symmetric multiverse as one part of a CP symmetric set of persons.
In line with Max Tegmarks idea, my proposal is, that we could be long distance entangled with at least one instant entangled anti-copy person living inside a Charge and Parity symmetric anti-material copy Universe.
In that case we could construct a causal explanation for Libet’s strange results between RPI and RPII, because new statistical difference research on RPI and RPII of extended Libet experiments described here could give answer on the number of participating copy persons living inside the same number of copy universes.
Quantum FFF Theory ( Function Follows Form) assumes that there are 8 or even 12 CP symmetric universes which are entangled down to each quantum in our raspberry shaped multiverse.
Conclusion: future statistical experimental differences between human RPI and RPII should give answer on the real number of univeres.
Our human brain configuration seems to be a prefered tool to understand the number of multiverses above others.
Wikipedia says: “Democracy is a form of government in which all eligible citizens participate equally”.
Free will in a multiverse seems to be based on: all instant entangled ideas of copy persons living in all CP symmetric copy universes, have the same possibility to Veto an act and participate equally.
A short introduction to the Quantum FFF model.
Quote: " Bohm’s ideas involve non-local hidden reality, in which everything depends on everything. In his universe, something happening in a distant galaxy is influencing you right now and vice versa, however minor the effect."
See New scientist article: "Quantum weirdness may hide an orderly reality after all".
The idea is that the parity symmetry between material and anti material entangled copy universes is assumed to be the origin of two interfering photons at long distance.
The left slit in one universe should function as the right slit in the other universe.