more from Peter Simons

Single Idea 12820

[catalogued under 9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects]

Full Idea

If we reject extensionality in mereology, it has as a consequence that more than one object may have exactly the same parts at the same time, and hence occupy the same position.


'Extensionality' says 'same parts - same thing'

Gist of Idea

Without extensional mereology two objects can occupy the same position


Peter Simons (Parts [1987], Intro)

Book Reference

Simons,Peter: 'Parts: a Study in Ontology' [OUP 1987], p.3

A Reaction

Simons defends this claim. I'm unconvinced that we must choose between the two views. The same parts should ensure the same physical essence, which seems to guarantee the same identity. Not any old parts generate an essence.