ABSTRACT
What are the possibilities that information alternately realizes or rules out? It is convenient to think of possibilities as existing in possible worlds and a world as consisting of all possibilities realized in it. In our world, the actual world, Barack Obama was reelected president of the United States in 2012, dinosaurs once ruled the Earth, and the Earth resides in a spiral galaxy, the Milky Way. But in other worlds, Mitt Romney defeated Obama in the 2012 election, dinosaurs never arose, and the Milky Way galaxy never formed. A world in which Romney defeated Obama would share more features with, and thus be in some sense closer to, our world than one lacking a Milky Way. And yet, incompatible worlds, however similar they may be to each other in some respects, do not intersect but are wholly separate-each possible world is complete unto itself. Individuation of possible worlds is thus quite different from individuation of matter. From the vantage of materialism, particles are the things most separated from each other but also the things that are most real. From the vantage of information, by contrast, worlds are the things most separated from each other and also the things that are most real.
