 Everett’s version of the Wigner’s Friend story involved an observer \(A\) who knows the state function of some system \(S\), and knows that it is not an eigenstate of the measurement he is about to perform on it, and an observer \(B\) who is in possession of the state function of the composite system \(A{+}S\). Observer \(A\) believes that the outcome of his measurement on \(S\) will be randomly determined by the collapse rule 4b, hence \(A\) attributes to \(A{+}S\) a state describing \(A\) as having a determinate measurement result and \(S\) as having collapsed to the corresponding state. Observer \(B\), however, attributes the state function of the room after \(A\)’s measurement according to the deterministic rule 4a, hence \(B\) attributes to \(A{+}S\) an entangled state where, according to rule 3, neither \(A\) nor \(S\) even has a determinate quantum-mechanical state of its own. Everett argued that since \(A\) and \(B\) make incompatible state attributions to \(A{+}S\), the standard collapse theory yields a straightforward contradiction. 