 The claim of Deutsch, Brown, and Wallace is of a novel character that we should perhaps pause to examine. On the one hand, for anyone who, like Wallace, accepts the viability of a functionalist many-worlds understanding of quantum mechanics—and in particular accepts that it follows as a matter of functional and structural analysis that when the wave function develops suitable complex patterns these ipso facto describe what we should regard as worlds—the claim should be compelling. On the other hand, for those who reject the functional analysis and regard many worlds as ontologically inadequate (see Maudlin 2010), or who, like Vaidman (see the SEP entry on the  many-worlds interpretation of quantum mechanics),  accepts many worlds on non-functionalist grounds, the claim should seem empty. In other words, one has basically to have already accepted a strong version of many worlds and already rejected Bohm in order to feel the force of the claim. 