 The two most visible accounts in philosophy of science, the “layer-cake” and “mechanistic” accounts, mark polarized visions for the levels concept. The layer-cake account comprises a comprehensive conception that posits exhaustive stepwise compositional relations between all constituents of nature and strict correspondence between each putative level and a primary scientific discipline that studies the constituents occupying that level. The mechanistic account proposes a contextualized conception of ontological levels in nature that are defined in terms of constitutive parthood within a mechanism (Craver 2007: 188–189; Kaplan 2015: 20). The third account, Wimsatt’s “local maxima” account, has arguably received less mainstream attention in philosophy, and posits a more overarching framework for conceptualizing levels in science, covering both epistemic and ontological aspects. Though general, Wimsatt’s account is not comprehensive, admitting exceptions and multiple distinct criteria for characterizing levels that are congenial to both local and global conceptions.