With respect to genuine cognitive faculties, present synthetic characters inhabiting online virtual worlds are, to say the least, completely impaired. Current methods aimed at the creation of “immersive” virtual worlds only avatars and NPCs the illusion of mentality and, as such, will ultimately fail. Like behaviorism, this doomed approach focuses only on the inputs and outputs of virtual characters and ignores the rich mental structures that are essential for any truly realistic social environment. While this “deceptive” tactic may be suitable so long as a human is in the driver's seat compensating for the mental deficit, truly convincing autonomous synthetic characters must possess genuine mental states, which can only result from a formal theory of mind. We report here on our attempt to invent part of such a theory, one that will enable artificial agents to have and reason about the beliefs of others, resulting in characters that can predict and manipulate the behavior of even human players. Furthermore, we present the “embodiment” of our recent successes: Eddie, a four year old child in Second Life who can reason about his own beliefs to draw conclusions in a manner that matches human children his age.