counterfactualists

Counterfactualists are scholars who focus on counterfactual conditionals—statements about what would have been the case if events had unfolded differently—and, in particular, on how such conditionals relate to causation, explanation, and learning. The label is often used for theorists who defend or develop the view that causal relations can be analyzed in terms of counterfactual dependence, typically using possible-world semantics to compare what happened with what would have happened under nearby alternative circumstances.

Historically, counterfactual reasoning became central to discussions of causation in the analytic tradition during the 20th century, with David Lewis’s influential possible-world account formalizing a general approach: A causes B if, had A not occurred, B would not have occurred. This program relies on a system of possible worlds and closest-world comparisons to evaluate whether counterfactuals hold. The framework was further developed by philosophers such as Robert Stalnaker and others, and it has been extended to questions of explanation, law, and science.

The counterfactual theory faces well-known challenges, including preemption and overdetermination cases where multiple factors could cause an outcome, making simple counterfactual dependence insufficient. Response theories, including interventionist accounts that emphasize manipulability and causal powers, offer alternative explanations for causal claims. Debates continue about the scope, semantics, and normative implications of counterfactual reasoning in causation and explanation.

Counterfactualists' work also informs areas such as philosophy of science, law, decision theory, and artificial intelligence, where understanding how changing one condition would alter outcomes supports models of explanation, prediction, and responsibility. Notable figures associated with the approach include David Lewis and, more broadly, researchers in possible-world semantics and causal modeling. See also counterfactuals, causation, and possible-world semantics.