Some theories suffer from the too-many-minds problem. Here I'll say that a theory suffers from a too-many-minds problem if the theory predicts that most minds are aberrant, say because they experience very unlikely scenarios (cream forming into words on their coffee, etc.) or because they live a truncated or disconnected life like Boltzmann brains.
Thinking about the main interpretations of Quantum Mechanics, I was struck by the following curious fact:
- Each main interpretation either suffers from the too-many-minds problem or requires a non-functionalist (typically, dualist) theory of mind or both.
- Everett's multiverse interpretation: Obviously suffers from the too-many-minds problem.
- The many-minds interpretation of Everett: Probably suffers from too-many-minds, but anyway requires dualism.
- The traveling minds interpretation: Doesn't suffer from too-many-minds, but is predicated on dualism. (OK, this isn't one of the leading interpretations, but I am a little fond of it, though I don't endorse it.)
- Bohm: If functionalism is true, Bohm suffers from too-many-minds. See Section 7 here.
- GRW collapse theories: There will be Boltzmann-brain type low-probability short-lived functional isomorphs of minds at the tails of the wavefunction, hence if functionalism is true, the theory suffers from too-many-minds.
- Consciousness-causes-collapse: It is hard to see how this could work without dualism. (In addition to the obvious point, I suspect that if minds are physical, the quantum Zeno effect is apt to prevent the emergence of consciousness.)
This is inspired by lots of recent discussions with Josh Rasmussen and Rob Koons.