 The “many interacting worlds” approach of Hall, Deckert, &amp; Wiseman (2014), independently advanced by Sebens (2015), retains particle trajectories but attempts to do away with a wave-function at the level of fundamental ontology. What takes its place is a large number of trajectories in configuration space, with each trajectory regarded as actual and as corresponding to the motions of a finite number of particles in physical space regarded as describing a world in its own right.  These interact in such a way as to mimic trajectories guided by a wave function: a coarse-grained density of worlds takes the place of \(\lvert \psi \rvert^2\). The velocities of the world-particles are required to at least approximately be related to their configurations via some smooth function on configuration space. This condition would be a rather surprising one for the sorts of large systems studied in statistical mechanics. Even more unmotivated from a classical perspective, the velocity function must be the gradient of a multivalued function that obeys a Bohr-Sommerfeld-like quantum condition. 