Responsibility and Blame: A Structural-Model Approach

Hana Chockler, Joseph Y. Halpern

Abstract: Causality is typically treated an all-or-nothing concept; either A is a cause of B or it is not. We extend the definition of causality introduced by Halpern and Pearl 2001a to take into account the degree of responsibility of A for B. For example, if someone wins an election 11-0, then each person who votes for him is less responsible for the victory than if he had won 6-5. We then define a notion of degree of blame, which takes into account an agent's epistemic state. Roughly speaking, the degree of blame of A for D is the expected degree of responsibility of A for B, taken over the epistemic state of an agent.