 Debates about theory reduction in early post-war philosophy of science suggested that this intuitive formulation required further nuance but also that it captured important insight about the structure of science. Rather than questioning the focus on intertheoretical reduction, much of the debate focused on specifying increasingly complex accounts of the relations between theories across different levels of organization (Oppenheim &amp; Putnam 1958; E. Nagel 1961; Schaffner 1967). In contrast, scientific pluralists challenged reductionism as fundamentally misrepresenting the relation between scientific theories and levels of organization. Pluralist challenges largely emerged in the context of wider scientific developments of the post-war period. For example, reductionist appeals to unification seemed to clash with the “cognitive revolution” of the 1960s and the rapid development of new scientific fields such as artificial intelligence, cognitive psychology, and generative linguistics (Gardner 1987). The cognitive revolution seemed to highlight that science does not progress through unification but rather through the emergence of novel fields that further proliferate the diversity of scientific concepts, methods, and theories.