 Even this intensional explication would still be vulnerable to the problems of irrelevant properties and the modus tollens paradox but for the adoption of a condition to exclude the occurrence of predicates that are not nomically relevant to the explanandum event from the explanans of an adequate scientific explanation. This criterion, known as the requirement of strict maximal specificity, permits the reformulation of Hempel’s four conditions of adequacy by replacing the redundant empirical content condition with this new requirement (Fetzer 1981; Salmon 1989). Explanations not only display the nomic expectability of their explanandum events—which, in the case of those that occur with high probability, would enable them to have been predicted, as Hempel proposed but—more importantly—explain them by specifying all and only those properties nomically responsible for their occurrence, even when they occur with low probability (Fetzer 1992).