[andrewflnr]

The password being persistently stored is not really a requirement here. That depends on the cryptosystem involved, among other things. What if I encrypt a ciphertext and throw away/forget the key?

Anyway, the constraint you're proposing here is, only passwords that can be encoded in all possible configurations of matter making up the earth? And you do have to contend with all possible configurations, if all you know is the size of the system, or even the mass and composition. As tedunangst put it, that's a lot of bits. I think we'll hit the 300-400 bit computational limit first.