Chalmers: virtual worlds are real

Most versions of the simulation hypothesis sound sceptical. If this is a simulation, nothing is real, and the cup in your hand isn’t a cup. Chalmers’ book argues at length that this doesn’t follow. A simulated cup is a real cup, made of bits instead of atoms. A simulated world is a real world with a different physics underneath. Being in a simulation wouldn’t show that the things around you don’t exist. It would show you were wrong about what they’re made of.

He calls the position simulation realism, and it rests on a distinction that’s easy to miss. “Real” can mean that it exists, that it has causal powers, that it isn’t an illusion, that it’s independent of minds, or that it’s genuine rather than fake. A simulated tree meets all of these except possibly the last. Chalmers argues it meets that one too: a virtual tree is a real virtual tree, the way a digital photograph is a real photograph.

The book also takes the computing question seriously, which is unusual in philosophy. Chalmers accepts that a perfect simulation of everything may be impossible. He argues it doesn’t need to be perfect. It only has to render what its inhabitants can observe, at the detail they can observe it. That’s the idea behind the Observation dial and the Matter floor, put as a philosophical claim instead of a number.

Any disagreement between this site and the book is about emphasis. Chalmers argues that the hypothesis shouldn’t trouble us. The sandbox shows how much computing the hypothesis takes, so you can judge how worried to be.