Grice on Pegasus

Speranza

The longstanding philosophical orthodoxy on counterfactuals holds, in part, that counterfactuals with metaphysically impossible antecedents are indiscriminately vacuously true. Drawing on a number of examples from across scientific practice, I argue that science routinely treats counterpossibles as non-vacuously true and also routinely treats other counterpossibles as false. In fact, the success of many central scientific endeavors requires that counterpossibles can be non-vacuously true or false. So the philosophical orthodoxy that counterpossibles are indiscriminately vacuously true is inconsistent with scientific practice. I argue that this provides a conclusive reason to reject the orthodoxy.