 More recently, Hüttemann and Love (2011) note that part-whole reduction in particular has become a widely-endorsed alternative to the Nagelian framework (see also Brigandt 2013: 77). In documenting some of the facets that this form of reduction has acquired in the intervening years, they put forward as two aspects of reductive explanation compositionality and causality (Hüttemann &amp; Love 2011: 4). In reductive contexts, both are expressed in levels-laden language. Compositionality, for instance, is couched in ‘levels’ in that the very notions of part and whole in biological contexts correspond to respectively lower- and higher-level status (cf. Kaiser 2015: 192; Winther 2006). This is reflected in the issues they raise for identifying and evaluating reductive explanations as reductive. One of these, “intrinsicality”, refers to the constraint of a part that it always be contained within, or inherent to, the whole to which it belongs (Hüttemann &amp; Love 2011: 9–10). ‘Levels’ offers one way of straightforwardly capturing this feature of part-whole relations (cf. 2011: 5). Another feature is “fundamentality,” which 