THE BASIC UNITS OF EXISTENCE

Whether the concrete entities of common sense are the ultimates of the physical world is a question closely related to the way objecthood is analysed. Some philosophers tend to view this intimate relationship as a mutual conceptual dependence, thus conflating the two issues. They seem to think that rejecting the primacy of physical substance is required when treating properties or events as basic, and that only a ‘pure’ substance view could regard objects as the fundamental units of physical reality. Without denying the closeness of the relationship, I object to the idea that there is a logical commitment here. I do not think, for instance, that a qualitative account of objecthood must treat exactly similar things as numerically identical, or that a belief in substance cannot survive without assuming a substratum or a so–called ‘individuating essence’. The notion of a basic unit of physical existence must be distinguished from that of an ultimate of metaphysical analysis, a primitive which accounts for other principles but itself is not explained by anything else.

Let ‘physically independent’ signify the condition of anything that is capable of existing in physical space, by itself, without requiring the support of anything else. Thus whether or not an entity is a part of something else, if it is independent in the sense explained (i.e., capable of supportless existence in space), then I will say that it is at least a potential unit of physical existence. Something is an actual unit of physical existence if it is detached, that is to say, not a part of a unit, in addition to being physically independent.