 Despite this history, developmental plasticity was marginalized as genetic explanations came to the fore in the mid-20th century (Sarkar 1998; Keller 2002). Against this background, embryologists such as Lewis Wolpert (1994) could ask whether an organism’s phenotype could be computed if we had the total description of the egg. Due to the above findings on organism-environment interaction (see section 3), a different view emerged that more seriously considers the environmental-responsiveness and plasticity of the developing phenotype. This view includes a shift from externalist to internalist or constructionist understandings of the organism-environment relationship (Godfrey-Smith 1996). While the externalist view – the orthodox view in evolutionary theory – conceptualizes properties of organisms as a result of their environments (i.e. natural selection targeting genetic programs), the internalist view sees “one set of organic properties in terms of other internal or intrinsic properties of the organic system” (Godfrey-Smith 1996: 30). According to these two accounts, organisms occupy an environment that covaries with them or that is largely independent of their variation. The above research in developmental evolution suggests a switch from an externalist to a constructionist perspective, in which the organism actively molds its internal states and responds to and alters its external environment (see Laland et al. 2014, 2015). In addition, in this framework also the causal role of the environment becomes more complex. It now includes the idea that the environment has active agency that can determine the phenotype. Rather than conceptualizing the environment as nothing but a passive filter for evolution, in this view the environment plays a role in actuating the phenotype in addition to selecting it (Moczek 2015; Gilbert &amp; Epel 2015).