Abstract
Certain rhetoric‐as‐epistemic theorists have held that consensus is the only criterion by which knowledge claims are assessed; their opponents have replied that consensus is not an epistemological criterion at all. Opponents of the epistemic view believe consensus is overruled by direct empirical observation. The present study proposes a compromise and argues that knowledge is a system of claims based on observation, experience, authority, and consensus. Hence a knowledge system is a socially coordinated, linguistically based network of propositions grounded in a reality external to discourse. Rhetoric therefore plays an inherent and significant, but not all‐encompassing, role in the formation of a knowledge system. The usefulness of this systemic model of knowledge is illustrated by applying it to the rhetorical analysis of Darwin's Origin of the Species.