 Whereas some engineering-inspired systems biologists search for functional units or modules in biological networks, another line of research emphasizes the need for a ‘global’ approach inspired by dynamical systems theory (Huang et al. 2009; Jaeger &amp; Crombach 2012). Drawing on Waddington’s idea of the epigenetic landscape of cell differentiation, the global approach represents dynamical states in a network through vectors, attractors, and trajectories in a state space (Huang 2012; for a philosophical analysis, see Fagan 2012). The framework explores how inherent mathematical properties of the network architectures may constrain developmental and evolutionary processes, in a way analogous to how laws of motion constrain the possible planetary movements (Goodwin et al. 1993). The global approach is sometimes highlighted as being in opposition to mechanistic or “modular” engineering approaches (Huang 2011; Fagan 2016). Controversies of this kind can reveal interesting differences in research aims as well as different standards for models and explanation present in systems biology  (Section 5.1).