Cause, Responsibility, and Blame: oA Structural-Model Approach
  A definition of causality introduced by Halpern and Pearl, which uses
structural equations, is reviewed. A more refined definition is then
considered, which takes into account issues of normality and typicality, which
are well known to affect causal ascriptions. Causality is typically an
all-or-nothing notion: either A is a cause of B or it is not. An extension of
the definition of causality to capture notions of degree of responsibility and
degree of blame, due to Chockler and Halpern, is reviewed. 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. Degree of blame takes into
account an agent's epistemic state. Roughly speaking, the degree of blame of A
for B is the expected degree of responsibility of A for B, taken over the
epistemic state of an agent. Finally, the structural-equations definition of
causality is compared to Wright's NESS test.
