That's a lot of our daily experience in the world today. Maybe it has always been thus, living in worlds of constructed realities.
The simulacrum is often defined as a copy with no original, or as Gilles Deleuze (1990) describes it, “the simulacrum is an image without resemblance”. Baudrillard argues that a simulacrum is not a copy of the real, but becomes truth in its own right, aka the hyperreal. He created four steps of reproduction: (1) basic reflection of reality, (2) perversion of reality; (3) pretence of reality (where there is no model); and (4) simulacrum, which "bears no relation to any reality whatsoever".
And at the Stanford encyclopedia of philosophy
(Links via S&M's The economy as hyperreality)