Like to hear a vampire folk tale?" Sarasti asked."Vampires have folk tales?"He took it for a yes. "A laser is assigned to find the darkness. Since it lives in a room without doors, or windows, or any other source of light, it thinks this will be easy. But everywhere it turns it sees brightness. Every wall, every piece of furniture it points at is brightly lit. Eventually it concludes there is no darkness, that light is everywhere.
Peter Watts, Blindsight
perception, perception-and-reality