I agree with a great deal in Helen Steward's paper. I am especially sympathetic to her suggestion that we gain metaphysical illumination by considering various ways in which we arrive at ideas of certain kinds of individuals by abstraction from those of more basic kinds. My aim is to pursue that suggestion by exploring the proposal that a grounding node in this form of abstraction may be characterized by Exclusivity in spatial location. Steward claims that we arrive at our ideas (...) of specific events and processes by different modes of abstraction in cases where a more basic persisting individual undergoes some kind of change. I argue that the most basic individuals in this hierarchy of abstraction are enduring substances that occupy their spatial location exclusively at all times: no two such substances are ever precisely collocated. (shrink)