### Single Idea 8420

#### [catalogued under 19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds]

Full Idea

I identify a proposition with the set of possible worlds where it is true.

Gist of Idea

A proposition is a set of possible worlds where it is true

Source

David Lewis (Causation [1973], p.193)

Book Reference

'Causation', ed/tr. Sosa,E. /Tooley,M. [OUP 1993], p.193

A Reaction

As it stands, I'm baffled by this. How can 'it is raining' be a set of possible worlds? I assume it expands to refer to the truth-conditions, among possibilities as well as actualities. 'It is raining' fits all worlds where it is raining.