 Few papers in the philosophy of science have produced such a voluminous literature. In a “Postscript”, Hempel addressed a few of the suggestions that have been advanced to analyze the paradoxical quality of the argument (Hempel 1965a). Several were intent upon explaining them quantitatively on the ground that, for example, there are many more non-black things than black things or that the probability of being non-black is much great than the probability of being a raven, whereas others appealed to Bayesian principles and suggested that the prior probability for ravens being black makes testing non-ravens of considerably less relative risk. Hempel replied that even the existence of a quantitative measure of evidential support poses no challenge to his conclusion that the paradoxical cases—non-black non-ravens, such as white shoes—are confirmatory.