 While many twentieth century American process thinkers were influenced by Whitehead, some turned elsewhere or went their own ways. For example, W. H. Sheldon championed a largely dialectical view of the dynamic nature of reality with process as a principle of conflict resolution. Wilfrid Sellars, one of the great figures in post-war analytical philosophy, worked out what appears to be the first consistently nominalist and naturalist system ever developed in the history of Western philosophy; this is often overlooked, however, since the system relies on a process ontology that Sellars only briefly sketched but never elaborated. Naturalism implies a nominalist account of properties, Sellars argued, which in turn can only succeed if we take qualia to be aspects of processes—by categorizing blue as sensing-blue-ly, we can make better sense of how physical processes engender sensory contents (Sellars 1981). With the envisaged process-based solution to the body-sensory problem, which in many ways anticipates current ideas of “embodied cognition,” Sellars could further suggest a new process-based re-interpretation of intentionality. Any kind of content, Sellars argued, from the lowliest sensory content in bacteria to the norm-governed contents of conceptual experience to the contents of scientific theories, is nothing else but a way of functioning. Taking over from Sellars the idea that content is function, present-day functionalist theories of mind and cognition typically fail to acknowledge Sellars and thereby miss the decisive element for a successful functionalist ‘reduction’ of intentionality and the mental, namely, that the reductive basis, functions, are not static input-output tables but ongoing processes in natural systems that realize, in this ongoingness, normative socio-cultural practices (Seibt 2016). Recently American process metaphysics gained another important voice in Nicholas Rescher who, like Sellars, consistently pursued a systematic approach in philosophy. Rescher made important contributions to all philosophical disciplines; originally these were framed as components of a system of “methodological pragmatism” and “pragmatic idealism”. In the mid-1990s, however, Rescher sketched a process metaphysical embedding for his system, using familiar philosophical terminology, and thus presented the first systematic overview of the explanatory potential of a non-Whiteheadian process metaphysics that forfeits technical expenditure and operates with a notion of process that is close to our common-sense understanding of developments. In parallel, since the past four decades and with increasing intensity, researchers working in the intersection of ontology and linguistics, in philosophy of mind and cognitive science, in philosophy of biology or of quantum physics, have addressed specific questions in these areas with greater attention to types of processes and processual structures. These more targeted investigations will be taken up below.