Full Idea
Stalnaker proposes that a conditional is true if its consequent is true in the minimal revision in which the antecedent is true, that is, in the most similar possible world in which the antecedent is true.
Gist of Idea
Conditionals are true if minimal revision of the antecedent verifies the consequent
Source
report of Robert C. Stalnaker (works [1970]) by Stephen Read - Thinking About Logic Ch.3
Book Reference
Read,Stephen: 'Thinking About Logic' [OUP 1995], p.82
A Reaction
A similar account of counterfactuals was taken up by Lewis to give a (rather dubious) account of causation.