This article argues that Thoreau's concept of “labor” presented as a defense of poiesis—any generative, world-altering activity. Thoreau understood Nature's labor as the ultimate creation for humans to imitate. Human labor best approached this ideal in the absence of market-based divisions of labor, particularly when mental and physical labor were united (even undifferentiated beyond their contemporary, reified distinction, a distinction which deeply troubled Thoreau). Thoreau's epistemology undergirds my discussion of his theory of labor. As I argue, his attempts to transcend divisions between subject and object, between ideal and material—divisions pertinent to his intellectual influences and interlocutors—were isomorphic to his attempts to transcend divisions of mental and physical labor, insofar as sensuous knowing itself was laborious. As Thoreau sought to know Nature and bring human labor closer to it, he expressed a consistent, dialectically complex philosophy, in which political economy and aesthetics, science and poetry, ran in parallel.