In this essay I consider the relation between ontological starting points, harm reduction, and responsibilization. I begin with a brief discussion of the dominant “modern form of ontology” and its relation to familiar notions of morality and biopolitics. I then consider what I call the typical model of harm reduction as an illustration of the enactment of this ontology and how this results in what we call responsibilization. I then briefly and critically engage a recent and influential alternative ontology offered by a prominent social theorist, and consider its shortcomings in taking up a Levinasian conception of responsibility. Finally, and in response to this critique, I turn to the unique case of Vancouver, Canada and the enactment of what I call a politics of world-building, through which political agonists are in the process of creating a new world characterized as attuned with itself.