Probability and objectivity in deterministic and indeterministic situations

This paper pursues the question, “To what extent does the propensity approach to probability contribute to plausible solutions to various anomalies which occur in quantum mechanics?” The position I shall defend is that of the three interpretations — the frequency, the subjective, and the propensity — only the third accommodates the possibility, in principle, of providing a realistic interpretation of ontic indeterminism. If these considerations are correct, then they lend support to Popper's contention that the propensity construction tends to remove (at least some of) the mystery from quantum phenomena.