 Another critic is Duwell, who (contra Steane) accepts the QPT (Duwell 2018a), but nevertheless denies that it uniquely supports the MWI (Duwell 2007). Considering the phase relations between the terms in a superposition such as (2) is crucially important when evaluating a quantum algorithm’s computational efficiency. Phase relations, however, are global properties of a state. Thus a quantum computation, Duwell argues, does not consist solely of local parallel computations. But in this case, the QPT does not uniquely support the MWI over other explanations.