Page "Counterfactual conditional" Paragraph 28

Counterfactual conditionals may also be evaluated using the so-called Ramsey test: A > B holds if and only if the addition of A to the current body of knowledge has B as a consequence.

This condition relates counterfactual conditionals to belief revision, as the evaluation of A > B can be done by first revising the current knowledge with A and then checking whether B is true in what results.

Revising is easy when A is consistent with the current beliefs, but can be hard otherwise.

Every semantics for belief revision can be used for evaluating conditional statements.

Conversely, every method for evaluating conditionals can be seen as a way for performing revision.