 According to Lewis (1986b), intermediate chances are incompatible with determinism. Loewer (2004) agrees that intermediate propensities are incompatible with determinism, understanding those to be essentially dynamical: “they specify the degree to which one state has a tendency to cause another” (15). But he argues that chances are best understood along Lewisian best-system lines, and that there is no reason to limit them to dynamical chances. In particular, best-system chances may also attach to initial conditions: adding to the dynamical laws a probability assignment, or distribution, over initial conditions may provide a substantial gain in strength with relatively little cost in simplicity. Science furnishes important examples of deterministic theories with such initial-condition probabilities. Adding the so-called micro-canonical distribution to Newton’s laws (and the assumption that the distant past had low entropy) yields all of statistical mechanics; adding the so-called quantum equilibrium distribution to Bohm’s dynamical laws yields standard quantum mechanics. Indeed, this contact with actual science is one of the selling points of best-system analyses. See Schwarz (2016) for further selling points.