Single Idea 8554

[catalogued under 10. Modality / B. Possibility / 1. Possibility]

Full Idea

The ways in which a given thing can be different in different possible worlds depend on the ways in which such a thing can be different at different times in the actual world.

Gist of Idea

Possible difference across worlds depends on difference across time in the actual world

Source

Sydney Shoemaker (Causality and Properties [1980], §05)

Book Reference

Shoemaker,Sydney: 'Identity, Cause and Mind' [OUP 2003], p.218


A Reaction

Where change in a thing is possible across time in the actual world seems to require a combination of experiment and imagination. Unimaginability does not entail necessity, but it may be the best guide we have got.