Probabilistic Inference and the Concept of Total Evidence

1. Introduction. My purpose is to examine a cluster of issues centering around the so-called statistical syllogism and the concept of total evidence. The kind of paradox that is alleged to arise from uninhibited use of the statistical syllogism is of the following sort. The probability that Jones will live at least fifteen years given that he is now between fifty and sixty years of age is r. Jones is (1) now between fifty and sixty years of age. Therefore, the probability that Jones will live at least fifteen years is r.