 The first category mainly contains classical and logical concepts of  probability.[47]  Classical concepts define probability through the equal possibility of states of affairs. Logical concepts focus on evidential support for the truth of propositions. The most prominent variants of the second category are Bayesian theories of probability and mathematical representations of subjective expectation. The last category comprises frequentist and propensity interpretations of  probability.[48]  For frequentists, probability is the limit of a relative frequency in a series of events; for the propensity view, it is an irreducible feature of the physical world.