Emergent measure-dependent probabilities from modified quantum dynamics without state-vector reduction

Counting outcomes is the obvious algorithm for generating probabilities in quantum mechanics without state-vector reduction (i.e., many-worlds). This procedure has usually been rejected because for purely linear dynamics it g ives results in disagreement with experiment. Here it is shown that if non- linear decoherence effects (previously proposed by other authors) are combi ned with an exponential time dependence of the scale for the non-linear eff ects the correct measure-dependent probabilities can emerge via outcome cou nting, without the addition of any stochastic fields or metaphysical hypoth eses.