Many Worlds and A priori Knowledge

1. If MWI is true then all physical possibilities are realized (Saunders 1998)
2. All realized possibilities are decoherent with each other
3. Decoherence implies that no experience in the sense physics puts behind this term could transcend the actual physical possibility [to use the conventional term “world”] of an observer
4. Hence, no observer in one world could have some experience about what is going on in a different world
5. Still, observers could have some knowledge about decoherent worlds
6. Experiential or non-experiential [a priori] knowledge
7. Therefore, observers could have [some] a priori knowledge about decoherent worlds