The technological ability to emulate a convincing world is plausible in the not-so-distant future. We additionally know that the motivation to create one already exists, given the huge popularity of video games, and the amount of money and effort put into making them. A big difference, however, between a current-day video game and this potential game of tomorrow, is that the player of a current game knows she is playing a game. Could we really be in a game and not know it?