Is it possible for reality as a whole to be part of itself? Can the world appear within itself without thereby undermining the consistency of our thought and knowledge-claims concerning more local matters of fact? This is a question on which Markus Gabriel and Graham Priest disagree. Gabriel argues that the world cannot exist precisely because it is understood to be an absolutely totality. Priest responds by developing a special form of mereology according to which reality is a single all-encompassing whole, everything, which counts itself among its denizens. Their disagreement results in a debate about everything and nothing: Gabriel argues that we experience nothingness once we overcome our urge to contain reality in an all-encompassing thought, whereas Priest develops an account of nothing according to which it is the ground of absolutely everything. A debate about everything and nothing, but also a reflection on the very possibility of metaphysics.