In the 1910s and 1920s, Austrian thinkers Josef Popper-Lynkeus (1838–1921) and Otto Neurath (1882–1945) ascended as the main advocates of a heterodox, biophysical approach to economic science dubbed the “Other Austrian Economics”. Their ideas included an emphasis on economic planning based on calculation in kind as means to regulate production and distribution processes toward improved living standards for all. Natural resource flow accounting posed as the main method through which they collected empirical evidence in order to develop new policy-relevant economic theories. This paper analyzes in detail what the ontological and epistemological assumptions underlying their resource flow accounting were, as well as how facts and values interplayed in their argumentation for calculation in kind as a key tool for economic science. Based on seminal works of Neurath and Popper-Lynkeus concerning the subject of the factual nature of such socioecological flows and stocks of matter and energy, the empirical character of their assessments can hardly be denied, while a genuine concern for the role played by value-based judgements in decisions about production and consumption is recurrent. They faced head-on the challenges posed by incommensurable values, and believed value-based judgements are political decisions. The more information there is about alternative economic plans, the better these decisions would be, especially in terms of a materially and energetically rational relationship between nature and society.