To quote from a quote in David Wallace's The Emergent Multiverse "Davies: so the parallel universes are cheap on assumptions but expensive on universes. Deutsc

To quote from a quote in David Wallace's The Emergent Multiverse "Davies: so the parallel universes are cheap on assumptions but expensive on universes. Deutsch: Exactly right. In physics we always try to make things cheap on assumptions. (Interview between Paul Davies and David Deutsch)"