Abstract
Despite their substantial appeal, closure principles have fallen on hard times. Both anti-luck conditions on knowledge and the defeasibility of knowledge look to be in tension with natural ways of articulating single-premise closure principles. The project of this paper is to show that plausible theses in the epistemology of testimony face problems structurally identical to those faced by closure principles. First I show how Lasonen-Aarnio’s claim that there is a tension between single premise closure and anti-luck constraints on knowledge can be extended to make trouble for transmission theses. Second, I show how Schechter’s claim that there is a tension between single premise closure and the thought that knowledge is defeasible can be extended to make trouble for transmission theses. I end the paper by sketching the consequences of this trouble for the dialectic in the epistemology of testimony.