counterfactualsstatements

Counterfactual statements, also referred to as counterfactuals, are conditional propositions about what would be the case if a condition different from the actual world were true. They are typically formulated as “If A had happened, B would have happened” or “If A were the case, B would be the case,” with the antecedent A describing a nonactual or counterfactual situation.

Most influential accounts treat counterfactuals using possible-world semantics. A counterfactual is true only if, in the closest possible world where A holds, B also holds. The notion of closeness is determined by factors such as similarity of events, which background conditions are held fixed, and normative or actual-orderings of worlds. This approach distinguishes counterfactuals from material implication, where a false antecedent makes the conditional vacuously true, a feature that often misaligns with everyday and scientific reasoning about dependence and causation.

Counterfactuals come in several varieties. Subjunctive or counterfactual conditionals concern hypothetical scenarios that are not actual. Causal conditionals emphasize how A would have influenced B given underlying causal structures. In linguistics, researchers study mood, context-sensitivity, and assumptions like ceteris paribus (all else being equal) that affect interpretation.

Applications span philosophy, especially theories of causation and explanation, to formal decision theory, law, and historiography, where reasoning about alternative outcomes is central. Challenges include cases of preemption or overdetermination, where multiple factors could have caused an outcome, and situations in which irrelevant background factors alter which possible-worlds are considered closest.

See also: counterfactual theory of causation, subjunctive mood, possible-world semantics.