 Here is how AC works in this example. S influences W along two different paths: the direct path \(S \rightarrow W\) and the indirect path \(S \rightarrow B \rightarrow W\). These two paths interact in such a way that they cancel each other out, and the value of S makes no net difference to the value of W. However, by holding B fixed at its actual value of 0, we eliminate the influence of S on W along that path. The result is that we isolate the contribution that S made to W along the direct path. AC defines actual causation as a particular kind of path-specific effect.