This paper looks at the question of what regions of space are possibly exactly occupied by a material object.

Suppose that a material object is gunky: all of its parts are located in space, and each of its parts has a proper part. Does it follow from this hypothesis that the space in which that object resides must itself be gunky? I argue that it does not. There is room for gunky objects in a space that decomposes without remainder into mereological simples.

This paper concerns the structure of any spatially extended things, including regions of space or spacetime. I shall use intuitions about the quantity of extended things to argue for a dichotomy: either a given finite extended thing is point-free gunk, that is, it has no points as parts, or it is made of grit, that is there are only finitely many points.

An extraordinary and challenging synthesis of ideas uniting Quantum Theory, and the theories of Computation, Knowledge and Evolution, Deutsch's extraordinary book explores the deep connections between these strands which reveal the fabric ...