Posthuman Blues

I've been mulling over the "Dust Hypothesis" advanced in Greg Egan's "Permutation City." The DH suggests that innumerable alternate universes exist, flawlessly creating themselves from random "noise" to match prespecified template patterns. This implies that our seeming existence could rapidly blink on and off; we'd never be the wiser. Are our physical "constants" being rewritten and introduced into "our" spacetime by an external force? I don't think there's a way to tell short of finding a blatant flaw (or deliberate message) in the universe's system architecture.