Single Idea 4038

[catalogued under 8. Modes of Existence / B. Properties / 11. Properties as Sets]

Full Idea

Lewis agrees that properties cannot be sets of their actual instances, but claims they can be sets of their possible instances. This would distinguish coextensive properties like being cordate and renate, since they might be separated.


Renate means 'has kidneys' and cordate means 'has a heart'. In the actual world they are never found separately

Gist of Idea

Properties are sets of their possible instances (which separates 'renate' from 'cordate')


report of David Lewis (Modal Realism at Work: Properties [1986]) by DH Mellor / A Oliver - Introduction to 'Properties' 10

Book Reference

'Properties', ed/tr. Mellor,D.H. /Oliver,A [OUP 1997], p.23

A Reaction

Sounds wrong. Two properties could be obviously different even if they could never be separated. In this world a creature might briefly survive without kidneys.