Abstract

All parts of mereologically ‘gunky’ entities have proper parts. All parts relevant to mereologically ‘junky’ entities *are* proper parts. This essay explores the application of gunk and junk beyond the standard category of material object. One such application yields what is here dubbed ‘deep’ gunk and junk: a material entity x all of whose intrinsic elements from any fundamental ontological category C either have proper parts from C that also are intrinsic elements of x, or are proper parts of entities from C that also are intrinsic elements of x. In addition to being independently interesting, these mereological structures pose a challenge to the bare particular ontology of substance. For bare particulars standardly are assumed to be mereologically simple, yet a deep gunky or junky entity requires any associated bare particulars to be complex. The essay closes by examining the bare particular theorist’s prospects for answering this challenge.