COINCIDENT ENTITIES

Coincident entities, if there were such things, would be distinct objects occupying exactly the same space at exactly the same time. The most difficult examples of coincident entities to explain away are those in which the two objects in question exist for exactly the same time and in exactly the same space for all the time that they exist, but differ in their modal properties. Consider two lumps of clay, one of which is shaped like the bottom half of a statue and the other like the top half of a statue. At the moment that those lumps are stuck together two distinct objects are brought into existence. One is a larger lump of clay composed of the two lumps. The other is a statue. When the original two lumps are again separated both the larger lump and the statue cease to exist. The larger lump and the statue are spatially and temporally coincident, but they are not identical. For instance, it is true of the lump that it could have had a completely different shape, but this is not true of the statue.

In spite of such very plausible examples, coincident entities would be very odd things. If there were any, they would have to have every spatial region in common at the time at which they were coincident. At that time, therefore, they would have exactly the same molecular substructure.