Abstract

I propose that testimony is subject to a norm that is backed by a credibility sanction: whenever the norm is violated, it is appropriate for the testifier to lose some credibility for their future testimony. This is one of a family of sanction-based norms, where violation of the norm makes it appropriate to lose some power; in this case, the power to induce belief through testimony. The applicability of the credibility norm to testimony follows from the epistemology of testimony, in that false or unjustified testimony weakens the reason for belief that is provided by the speaker's future testimony.