Is our universe real?
"This the classic Cartesian question. It essentially asks, how do we know that what we see around us is the real deal, and not some grand illusion perpetuated by an unseen force (who René Descartes referred to as the hypothesized ‘evil demon')? More recently, the question has been reframed as the "brain in a vat" problem, or the Simulation Argument. And it could very well be that we're the products of an elaborate simulation. A deeper question to ask, therefore, is whether the civilization running the simulation is also in a simulation — a kind of supercomputer regression (or simulationception). Moreover, we may not be who we think we are. Assuming that the people running the simulation are also taking part in it, our true identities may be temporarily suppressed, to heighten the realness of the experience. This philosophical conundrum also forces us to re-evaluate what we mean by "real." Modal realists argue that if the universe around us seems rational (as opposed to it being dreamy, incoherent, or lawless), then we have no choice but to declare it as being real and genuine. Or maybe, as Cipher said after eating a piece of "simulated" steak in The Matrix, "Ignorance is bliss."
-http://io9.gizmodo.com/
