When Evidential Demands Sustain or Terminate Inquiry: A Structural Analysis of Public Discourse

Appeals to evidence are a pervasive feature of contemporary public discourse. They are commonly regarded as neutral epistemic demands that advance inquiry by requiring claims to be justified through evidence. Yet evidential demands often produce divergent outcomes. In some cases, they facilitate revision, learning, and the refinement of shared understanding. In others, they appear to terminate inquiry by restricting the range of admissible responses without resolving the underlying disagreement. This paper argues that evidential demands are not functionally uniform. Rather than treating them as a single epistemic practice, it proposes that evidential demands can perform at least two distinct functions within public discourse. Some operate as inquiry-sustaining demands that support the revision and development of shared understanding. Others operate as inquiry-terminating demands that stabilize existing evaluative conditions and limit the scope of contestation. The same evidential demand may perform either function depending on how the inquiry in question is configured. The paper develops a structural analysis of evidential demands by focusing not on what counts as evidence, but on the role evidential demands play within ongoing public disagreement. To clarify this role, it formulates a set of diagnostic conditions for distinguishing inquiry-sustaining from inquiry-terminating demands. These conditions include level alignment between claims and demands, explicit articulation of premises, generative possibility of the requested evidence, temporal openness of inquiry, and reciprocal applicability of evidential standards. The contribution of the paper is not a theory of evidence or a general theory of public inquiry. Instead, it offers a transferable framework for analyzing the functions of evidential demands in public discourse. By distinguishing between different ways in which evidential demands structure disagreement, the paper explains how formally similar appeals to evidence can either sustain inquiry or contribute to its termination.