 Despite the familiarity of scientists and philosophers with the levels concept, calls for its dismissal or de-emphasis in the scientific lexicon are increasingly common (Eronen 2013, 2015; Guttman 1976; Ladyman &amp; Ross 2007; Potochnik &amp; McGill 2012; Rueger &amp; McGivern 2010; Thalos 2013; for rebuttals see also DiFrisco 2017; Brooks 2017). For one thing, nature may simply be too messy to fit any layer-cake style picture. Consider as an illustration the putative level of “organisms.” Blue whales and yeast cells are both clearly organisms and thus should nominally be located at this level, but each comprises radically different kinds of entities with radically different properties (Potochnik &amp; McGill 2012). This may still be palatable, but when we consider the next lower level, namely the one indicated by the components of these organisms, the picture of levels as neat horizontal layers breaks down completely. The components of blue whales include things such as organs, tissues and cells, whereas yeast cells are composed of things like the cell membrane, nucleus and mitochondria (cf. Potochnik &amp; McGill 2012). Furthermore, the whale is in part composed of various symbionts, including gut bacteria. Such symbionts are at the same time components of the whale and organisms in themselves. Thus, the components of different kinds organisms do not form any homogeneous “level”.