What if there is no bottom to reality, and no outside around it?Simulation theory asks whether our world runs on a computer in some "realer" world. Religion asks whether a god made it. Physics asks what the smallest pieces are. Every one of these answers assumes the same thing: somewhere, there is a floor. The Filled Void asks what happens when you take the floor away, and follows the answer all the way down.Inside, you'll find:Why every possible arrangement of reality is real, and why that is less wild than it soundsWhy "Are we simulated?" loses its sting: nothing, anywhere, was ever madeWhy a god, a person and an ant have exactly the same standingWhat the strongest evidence about death can and cannot tell usHow the same few shapes, from sunflowers to galaxies, reveal the grammar of our worldSixteen serious objections, each stated at full strength and answeredThe book draws on physics (holography, the multiverse, the mathematics of infinity), on philosophy, and on Buddhist thought, with seven thought experiments that let you feel the arguments and a closing chapter that tells the whole idea in plain words.It is a book about what is left when every floor is removed: everything, and nothing, at once.