Pettit and Jackson
- A property P is causally relevant for bringing about an effect E iff E would have occurred under all ways of realizing P.
- Peacocke : no. suppose the fragile wing of a plane is relevant to its crashing and that it consists in cracks in the wing. But fragility could have been due to loose bolts, but that would not have led to the crash because this would have been checked on the ground.