Reality+: Virtual Worlds and the Problems of Philosophy

by David J. Chalmers

Here’s where we can run a version of the Simulation Riposte. We create a rich simulated world, with a simulation of George Berkeley inside it. Sim Berkeley tells us, “Appearance is reality.” Since there is no appearance of a simulation, there is, in actuality, no simulation. Sim Berkeley concludes, “I am not in a simulation. My experiences are all produced by ideas in God’s mind.” From our perspective, Sim Berkeley looks a bit ridiculous. He says he’s not in a simulation, but he is wrong: He is in a simulation. He says that appearance is reality, but there is a vast realm of reality beyond what appears to him. He says his experiences are produced by God, but in fact his experiences are produced by us, with the help of a computer. His world is sustained by the computer, not by ideas in God’s mind. Now, Berkeley might have some comebacks here. He could say that everything in our world is sustained by God’s mind, including the computer. But once we see that a computer can do the job, why do we need God? Berkeley could also say that even if reality goes beyond Sim Berkeley’s appearances, Sim Berkeley’s reality—the world of tables and chairs he perceives—is constituted by those appearances. What’s outside the simulation is outside Sim Berkeley’s world. Still, it’s hard to deny that if Sim Berkeley says he’s not in a simulation, he is wrong. This should make us suspicious of the principle that appearance is reality.