Single Idea 8425

[catalogued under 10. Modality / B. Possibility / 9. Counterfactuals]

Full Idea

A counterfactual is non-vacuously true iff it takes less of a departure from actuality to make the consequent true along with the antecedent than it does to make the antecedent true without the consequent.

Gist of Idea

For true counterfactuals, both antecedent and consequent true is closest to actuality


David Lewis (Causation [1973], p.197)

Book Reference

'Causation', ed/tr. Sosa,E. /Tooley,M. [OUP 1993], p.197

A Reaction

Almost every theory proposed by Lewis hangs on the meaning of the word 'close', as used here. If you visited twenty Earth-like worlds (watch Startrek?), it would be a struggle to decide their closeness to ours in rank order.