Strevens's Counterexample to Lewis's "Causation as Influence", and Degrees of Causation

Sungho Choi has criticised Michael Strevens's counterexample to DavidLewis's final theory of "token" causation, causation as "influence." Iargue that, even if Choi's points are correct, Strevens's counterexampleremains useful in revealing a shortcoming of Lewis's theory. Thisshortcoming is that Lewis's theory does not properly account for*degrees* of causation. That is, even if Choi's points are correct,Lewis's theory does not capture an intuition we have about the*comparative* causal statuses of those events involved in Strevens'scounterexample (we might, for example, intuit that Sylvie's ball-firingis *as much*/*more*/*less* a cause of the jar's shattering as/than isBruno's ball-firing).