Is the continued escalation of environmental problems indicative of an incompleteness in rationality or a failure of rationality? In their efforts to protect nature, environmentalists ostensibly abide by the findings of ecological science; yet environmental policy largely takes for granted the potential perfectibility of economic tools as rational representations of nature. Are these epistemologies commensurable? Which tools would constitute an appropriate language to articulate and ameliorate environmental problems? This dissertation is an ethnography of knowledge production at the intersection of ecology and economics. My field site is both a social group – the heterodox community of ecological economists – and an epistemic process – that group’s attempts to illuminate, articulate, and implement a distinction between the application of economic instruments to nature (orthodoxy) and their own efforts to incorporate ecological principles into economics (heterodoxy). I draw on ten years of participant-observation of environmental public policy, including in-depth interviews with foundational, emerging, and transient participants in heterodox efforts, and analysis of the epistemic content they produce. I theorize the process by which the social and epistemic practices of a social science – economics – might be rearticulated to comply with the epistemology of a natural science – ecology. This investigation of an interdisciplinary interface takes an interdisciplinary approach to analysis. I draw on the tools of sociological ethnography, science and technology studies (STS), and the science of ecology to examine the context in which economic tools are commensurated with ecological entities. I find that the epistemic project of ecological economics is seeking to operationalize a transition to heterodox environmental policy by valuing the epistemology of ecological knowledge at an equal level to the content of ecological knowledge. I theorize the possibility of an analytical inversion: a norm of calculation that grants primacy to the embeddedness of societies and economies in a biophysical context, and foregrounds the purpose and effects of calculation over efficiency in or parsimony of calculation. I explore whether a heterodox epistemic mission may require pluralist tension, even as its professed goal is the coherence of a concerted alternative. I draw the outlines of a theory of social and epistemic dynamics at an “unboundary,” a space of shared discourse containing demonstrably incompatible epistemic commitments in the service of pragmatic ends. This dissertation furthers our understanding of interdisciplinary knowledge creation, and of the practical challenges of developing a policy framework that respects ecological ontology.