 Similar to Lange’s stability theory, the invariance approach (most prominently advocated in EG1, EG2; Woodward 2000, 2002, 2003) also identifies the stability or invariance of a generalization as its key feature for performing the role of a law and figuring in explanations and predictions. As in Lange’s theory, to be invariant means for Woodward and Hitchcock to be true under several (not necessarily all) counterfactual suppositions. Despite this basic agreement there are important respects in which the invariance theory differs from Lange’s stability theory. In what follows we focus on the distinguishing features of the invariance approach: