 Together with the English legal scholar Sir Frederick Pollock, with whom he corresponded for many decades, Holmes also set a pair of questions for tort theory. The first is whether there is a general principle of liability underlying all of tort law or simply a miscellany of different causes of action. The Holmes/Pollock answer was affirmative: they each argued in their own way that the basis of liability was causing harm without justification or excuse. As Pollock put it: 