 Biological systems are often taken to be too contingent, diverse, and context-dependent to allow for derivation of laws or general principles akin to those found in physics (Burian et al. 1996). The quest for design principles and generic topological features in biology is therefore interesting test cases to explore such issues (Green 2015b; Moreno and Suárez 2020). A key issue in this debate is whether generalizable functions can be inferred from organizational structures, relatively independently of cellular, organismal, and environmental contexts. This issue has often been discussed as a question of multiple realizability, i.e. whether a higher-level state or property is relatively independent of the causal details or properties at a lower level because the system's structure determines the function. Systems biology bring new light to these debates, e.g., by discussing the extent to which network motifs provide concrete examples of this phenomenon (Fang 2020). Multiple realizability of functions via network motifs has also been argued to provide a design heuristic explored in synthetic biology, e.g., when engineering minimal genetic systems and artificial biochemical systems (Koskinen 2019). The search for network motifs and other functional units make apparent that assumptions of modularity are not completely abandoned. Rather, the notion of modularity may be reconfigured via strategies for structural decomposition of larger networks (Serban 2020). However, some systems biologists and philosophers have questioned whether functional ‘units’ can be meaningfully isolated from the workings of the network as a whole (DiFrisco and Jaeger 2019; Huang 2011; Isalan et al. 2008), thus casting new light on debates on reductionism and holism in the life sciences. A related question is how the enhanced focus on generic features of biological networks relates to mechanistic accounts of biological explanation  (Section 4.2).