 Systems biology research is sometimes divided into a systems-theoretical and a pragmatic stream (O’Malley and Dupré 2005). The former is historically related to the initial use of the term ‘systems biology’ in 1968, denoting the merging of systems theory and biology (Mesarović  1968).[1]  This definition has been taken up as providing a theoretical vision and reorientation also for modern systems biology (Wolkenhauer &amp; Mesarović 2005; Drack &amp; Wolkenhauer 2011). Systems-theoretical proponents view systems biology as an opportunity to revive important theoretical questions that for half a century stood in the shade of the success of experimental biology. Examples of such questions are what characterizes living systems and whether generic organizational principles can be identified (see  Section 3.2).  In contrast, the pragmatic stream views systems biology as a successor of genomics and as a powerful extension of molecular biology. This stream is sometimes referred to as molecular systems biology (De Backer et al. 2010), and practitioners within this field relate the emergence of systems biology to the production of data within genomics and other high-throughput technologies from the late 1990s and onwards (Güttinger &amp; Dupré 2016).