 A final representational feature is intrinsicality, i.e., how what is “internal” and “external” are explicitly or implicitly distinguished in reductive explanations. Wimsatt (1980) drew attention to the fact that every investigation must divide a system from its environment and that methodological reductionism favors attributions of causal responsibility to internal parts of a system rather than those deemed external (see also Wilson 2004). In the protein folding case, it appears that the failure of temporally indexed explanatory reduction involves the causal powers of something extrinsic to (an instance of) the process under scrutiny (i.e., the folding of a single amino acid chain). The presumption of atemporal, compositional relationships has encouraged a neglect of this distinction because nested part-whole relations are predicated on a prior individuation of a system from its environment (Hüttemann and Love 2011, Love and Hüttemann 2011). Kaiser’s (2015) idea that a reductive explanation must (among other things) represent each lower-level part of the explanation “in isolation” from other parts is one explicit attempt to engage representational questions related to intrinsicality  (Section 3.2).  Overall, this line of thought relates to the context-dependency objection  (Section 4.1),  but emphasizes the importance of functional dependency relations uncovered by attending to temporality in addition to structural organization.