Explanation and invariance in the special sciences

This paper describes an alternative to the common view that explanation in the special sciences involves subsumption under laws. According to this alt ernative, whether or not a generalization can be used to explain has to do with whether it is invariant rather than with whether it is lawful. A gener alization is invariant if it is stable or robust in the sense that it would continue to hold under a relevant class of changes. Unlike lawfulness, inv ariance comes in degrees and has other features that are well suited to cap ture the characteristics of explanatory generalizations in the special scie nces. For example, a generalization can be invariant even if it has excepti ons or holds only over a limited spatio-temporal interval. The notion of in variance can be used to resolve a number of dilemmas that arise in standard treatments of explanatory generalizations in the special sciences.