Could a consciousness comprise of just a single, false perception— that there are further memories and perceptions? What would it take for such a "mind" to manifest in our universe?
Probably almost nothing; I can't imagine the difference between this and an inert object, or even an instantaneous event. It has no real memory, so it doesn't need to exist for more than an instant.
(Uh, you can stop reading here if you want. Just a warning.)
This has some parallels to Bill Gosper's "HashLife", an implementation of Conway's Game of Life that effectively hashes every event at every scale and timescale. The simulation accelerates rapidly by skipping events whose cause and effect are already coded into those of larger events, and so on, up and up and up; every portion of the simulation ends up being a key for a value in the cosmic hash table. So who's to say what in the simulation is real, and what is symbolic of something more complex?
> Typically, a quantum Boltzmann brain would suddenly appear from the vacuum (alongside an equivalent amount of virtual antimatter), remain only long enough to have a single coherent thought or observation, and then disappear into the vacuum as suddenly as it appeared.