David Over (Durham University)

Understanding Counterfactuals

There is a rich psychological literature, in cognitive and social psychology, and judgment and decision making, on counterfactuals. Psychologists have intensively investigated the relation between counterfactuals and causal judgments, and between counterfactuals and feelings of regret. However, psychologists of reasoning, specifically, have neglected the study of counterfactuals and logical inferences. There has been only one major experimental study of counterfactuals and the inference of Modus Ponens, inferring B from A and a counterfactual "if A then B". There have been no experiments on the inference of centering for counterfactuals, inferring a counterfactual "if A then B" from "A & B". Both of these inferences are valid in the most influential logical and philosophical analyses of counterfactuals, and we know next to nothing, in the psychology of reasoning, about how people understand the logic of these conditionals, if we do not know whether they conform to the validity of these inferences. In this talk, I shall outline how my collaborators and I plan to overcome this limitation, in the psychology of counterfactuals, by using the new Bayesian / probabilistic approach to the study of human reasoning.