 The underlying reason why \(A \land \neg D\) can be pruned from the left side of  (1)  is that \(A \land \neg D\) is sufficient for \(C \lor E\), while the latter is not sufficient for the former in the given scenario. Now, an instantiation of \(C \lor E\) makes a difference as to whether or not \(B\) is instantiated—independently of \(A \land \neg D\). The converse is not true: an instantiation of \(A \land \neg D\) makes a difference as to whether or not \(B\) is instantiated, but not independently of \(C \lor E\) (see Baumgartner 2008: 340–346 and 2013: 90–96). This suggests the following requirement: a complex regularity for an effect must be a minimally necessary disjunction of minimally sufficient clusters for said effect. Indeed, given that each effect has at least two alternative causes, this seems to solve the problem of joint effects of a common cause.