Volume-weighted measure for eternal inflation

I propose a new volume-weighted probability measure for cosmological ``multiverse'' scenarios involving eternal inflation. The ``reheating-volume (RV) cutoff'' calculates the distribution of observable quantities on a portion of the reheating hypersurface that is conditioned to be finite. The RV measure is gauge-invariant, does not suffer from the ``youngness paradox,'' and is independent of initial conditions at the beginning of inflation. In slow-roll inflationary models with a scalar inflaton, the RV-regulated probability distributions can be obtained by solving nonlinear diffusion equations. I discuss possible applications of the new measure to ``landscape'' scenarios with bubble nucleation. As an illustration, I compute the predictions of the RV measure in a simple toy landscape.