1. These views on interlevel explanation, the metaphysics of reduction, interlevel causation, and emergence are all articulated in terms of a very specific idea of a “level of mechanisms” (introduced in Section 2.1.5) and do not apply to other notions of level, such as size scales, disciplinary differences, and levels of complexity (see Craver 2007a: Chapter 5 for a critical review). There is because of this considerable danger of equivocation and misunderstanding.