 Kellert’s discussion of “dynamic understanding” and Peter Smith’s critical remarks both overlap in their agreement that various robust or universal features of chaos are important for chaos studies The idea of focusing on universal features such as patterns, critical numbers, and so forth suggests that some form of unification account of explanation is what is at work in chaos explanations: group together all examples of chaotic behavior via universal patterns and other features (e.g., period doubling sequences). There is disagreement on the extent to which the methodologies of current chaos research present any radically new challenges to the project of scientific explanation. 